From cf697b9e34f116198a4dc97444ea8d680430c5c0 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 31 Oct 2025 11:56:39 +0100
Subject: [PATCH 01/21] fix: use type to better capture cache data

---
 .../src/build/build_cache.rs                  |  4 +-
 .../pixi_command_dispatcher/src/build/mod.rs  | 55 +++++++++++++++++++
 .../src/install_pixi/mod.rs                   |  2 +-
 .../src/source_build/mod.rs                   | 12 +++-
 .../src/source_build_cache_status/mod.rs      | 15 +++--
 .../tests/integration/main.rs                 | 13 +++--
 6 files changed, 85 insertions(+), 16 deletions(-)

diff --git a/crates/pixi_command_dispatcher/src/build/build_cache.rs b/crates/pixi_command_dispatcher/src/build/build_cache.rs
index c76324df6f..97a9988249 100644
--- a/crates/pixi_command_dispatcher/src/build/build_cache.rs
+++ b/crates/pixi_command_dispatcher/src/build/build_cache.rs
@@ -19,7 +19,7 @@ use thiserror::Error;
 use tokio::io::{AsyncReadExt, AsyncSeekExt, AsyncWriteExt};
 use xxhash_rust::xxh3::Xxh3;
 
-use crate::build::source_checkout_cache_key;
+use crate::build::{SourceCodeLocation, source_checkout_cache_key};
 
 /// A cache for caching build artifacts of a source checkout.
 #[derive(Clone)]
@@ -249,7 +249,7 @@ pub struct BuildHostPackage {
     pub repodata_record: RepoDataRecord,
 
     /// The source location from which the package was built.
-    pub source: Option<PinnedSourceSpec>,
+    pub source: Option<SourceCodeLocation>,
 }
 
 /// A cache entry returned by [`BuildCache::entry`] which enables
diff --git a/crates/pixi_command_dispatcher/src/build/mod.rs b/crates/pixi_command_dispatcher/src/build/mod.rs
index 38d5b68d79..3318d74bd4 100644
--- a/crates/pixi_command_dispatcher/src/build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build/mod.rs
@@ -8,6 +8,7 @@ mod move_file;
 pub(crate) mod source_metadata_cache;
 mod work_dir_key;
 
+use core::fmt;
 use std::hash::{Hash, Hasher};
 
 use base64::{Engine, engine::general_purpose::URL_SAFE_NO_PAD};
@@ -22,12 +23,66 @@ pub use dependencies::{
 };
 pub(crate) use move_file::{MoveError, move_file};
 use pixi_record::PinnedSourceSpec;
+use serde::{Deserialize, Serialize};
 use url::Url;
 pub use work_dir_key::{SourceRecordOrCheckout, WorkDirKey};
 use xxhash_rust::xxh3::Xxh3;
 
 const KNOWN_SUFFIXES: [&str; 3] = [".git", ".tar.gz", ".zip"];
 
+/// Stores the two possible locations for the source code,
+/// in the case of an out-of-tree source build.
+///
+/// Something which looks like:
+/// ```toml
+/// [package.build]
+/// source = { path = "some-path" }
+/// ```
+///
+/// We want to prefer that location for our cache checks
+#[derive(Debug, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
+pub struct SourceCodeLocation {
+    /// The location of the manifest and the possible source code
+    manifest_source: PinnedSourceSpec,
+    /// The location of the source code that should be queried and build
+    build_source: Option<PinnedSourceSpec>,
+}
+
+impl SourceCodeLocation {
+    pub fn new(manifest_source: PinnedSourceSpec, build_source: Option<PinnedSourceSpec>) -> Self {
+        Self {
+            manifest_source,
+            build_source,
+        }
+    }
+
+    /// Get the reference to the manifest source
+    pub fn manifest_source(&self) -> &PinnedSourceSpec {
+        &self.manifest_source
+    }
+
+    /// Get the pinned source spec to the actual source code
+    /// This is the normally the path to the manifest_source
+    /// but when set is the path to the build_source
+    pub fn source_code(&self) -> &PinnedSourceSpec {
+        self.build_source.as_ref().unwrap_or(&self.manifest_source)
+    }
+}
+
+impl std::fmt::Display for SourceCodeLocation {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "(manifest-src: {}, build-src: {})",
+            self.manifest_source(),
+            self.build_source
+                .as_ref()
+                .map(|build| format!("{}", build))
+                .unwrap_or("undefined".to_string())
+        )
+    }
+}
+
 /// Try to deduce a name from a url.
 fn pretty_url_name(url: &Url) -> String {
     if let Some(last_segment) = url
diff --git a/crates/pixi_command_dispatcher/src/install_pixi/mod.rs b/crates/pixi_command_dispatcher/src/install_pixi/mod.rs
index 98b6b1de63..beab694cc1 100644
--- a/crates/pixi_command_dispatcher/src/install_pixi/mod.rs
+++ b/crates/pixi_command_dispatcher/src/install_pixi/mod.rs
@@ -230,7 +230,7 @@ impl InstallPixiEnvironmentSpec {
                 force,
                 // When we install a pixi environment we always build in development mode.
                 build_profile: BuildProfile::Development,
-                build_source: None,
+                build_source: source_record.build_source.clone(),
             })
             .await?;
 
diff --git a/crates/pixi_command_dispatcher/src/source_build/mod.rs b/crates/pixi_command_dispatcher/src/source_build/mod.rs
index 7914bf8f3f..f90e5ae2d0 100644
--- a/crates/pixi_command_dispatcher/src/source_build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build/mod.rs
@@ -33,7 +33,7 @@ use crate::{
     build::{
         BuildCacheError, BuildHostEnvironment, BuildHostPackage, CachedBuild,
         CachedBuildSourceInfo, Dependencies, DependenciesError, MoveError, PackageBuildInputHash,
-        PixiRunExports, SourceRecordOrCheckout, WorkDirKey, move_file,
+        PixiRunExports, SourceCodeLocation, SourceRecordOrCheckout, WorkDirKey, move_file,
     },
     package_identifier::PackageIdentifier,
 };
@@ -147,7 +147,10 @@ impl SourceBuildSpec {
                 .source_build_cache_status(SourceBuildCacheStatusSpec {
                     package: self.package.clone(),
                     build_environment: self.build_environment.clone(),
-                    source: self.manifest_source.clone(),
+                    source: super::build::SourceCodeLocation::new(
+                        self.manifest_source.clone(),
+                        self.build_source.clone(),
+                    ),
                     channels: self.channels.clone(),
                     channel_config: self.channel_config.clone(),
                     enabled_protocols: self.enabled_protocols.clone(),
@@ -463,7 +466,10 @@ impl SourceBuildSpec {
                         .expect("the source record should be present in the result sources");
                     BuildHostPackage {
                         repodata_record,
-                        source: Some(source.manifest_source),
+                        source: Some(SourceCodeLocation::new(
+                            source.manifest_source,
+                            source.build_source,
+                        )),
                     }
                 }
             })
diff --git a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
index 544d7f80ff..6084d0b6ae 100644
--- a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
@@ -15,6 +15,7 @@ use crate::{
     PackageIdentifier, SourceCheckoutError,
     build::{
         BuildCacheEntry, BuildCacheError, BuildInput, CachedBuild, PackageBuildInputHashBuilder,
+        SourceCodeLocation,
     },
 };
 
@@ -35,7 +36,7 @@ pub struct SourceBuildCacheStatusSpec {
     pub package: PackageIdentifier,
 
     /// Describes the source location of the package to query.
-    pub source: PinnedSourceSpec,
+    pub source: SourceCodeLocation,
 
     /// The channels to use when building source packages.
     pub channels: Vec<ChannelUrl>,
@@ -135,7 +136,7 @@ impl SourceBuildCacheStatusSpec {
         };
         let (cached_build, build_cache_entry) = command_dispatcher
             .build_cache()
-            .entry(&self.source, &build_input)
+            .entry(&self.source.manifest_source(), &build_input)
             .await
             .map_err(SourceBuildCacheStatusError::BuildCache)
             .map_err(CommandDispatcherError::Failed)?;
@@ -176,13 +177,17 @@ impl SourceBuildCacheStatusSpec {
         let source = &self.source;
 
         // Immutable source records are always considered valid.
-        if source.is_immutable() {
+        if source.source_code().is_immutable() {
             return Ok(CachedBuildStatus::UpToDate(cached_build));
         }
 
         // Check if the project configuration has changed.
         let cached_build = match self
-            .check_package_configuration_changed(command_dispatcher, cached_build, source)
+            .check_package_configuration_changed(
+                command_dispatcher,
+                cached_build,
+                source.manifest_source(),
+            )
             .await?
         {
             CachedBuildStatus::UpToDate(cached_build) | CachedBuildStatus::New(cached_build) => {
@@ -196,7 +201,7 @@ impl SourceBuildCacheStatusSpec {
 
         // Determine if the package is out of date by checking the source
         let cached_build = match self
-            .check_source_out_of_date(command_dispatcher, cached_build, source)
+            .check_source_out_of_date(command_dispatcher, cached_build, source.source_code())
             .await?
         {
             CachedBuildStatus::UpToDate(cached_build) | CachedBuildStatus::New(cached_build) => {
diff --git a/crates/pixi_command_dispatcher/tests/integration/main.rs b/crates/pixi_command_dispatcher/tests/integration/main.rs
index 6d016344ad..11e41c518a 100644
--- a/crates/pixi_command_dispatcher/tests/integration/main.rs
+++ b/crates/pixi_command_dispatcher/tests/integration/main.rs
@@ -15,7 +15,7 @@ use pixi_build_frontend::{BackendOverride, InMemoryOverriddenBackends};
 use pixi_command_dispatcher::{
     BuildEnvironment, CacheDirs, CommandDispatcher, Executor, InstallPixiEnvironmentSpec,
     InstantiateToolEnvironmentSpec, PackageIdentifier, PixiEnvironmentSpec,
-    SourceBuildCacheStatusSpec,
+    SourceBuildCacheStatusSpec, build::SourceCodeLocation,
 };
 use pixi_config::default_channel_config;
 use pixi_record::PinnedPathSpec;
@@ -563,10 +563,13 @@ async fn source_build_cache_status_clear_works() {
 
     let spec = SourceBuildCacheStatusSpec {
         package: pkg,
-        source: PinnedPathSpec {
-            path: tmp_dir.path().to_string_lossy().into_owned().into(),
-        }
-        .into(),
+        source: SourceCodeLocation::new(
+            PinnedPathSpec {
+                path: tmp_dir.path().to_string_lossy().into_owned().into(),
+            }
+            .into(),
+            None,
+        ),
         channels: Vec::<ChannelUrl>::new(),
         build_environment: build_env,
         channel_config: default_channel_config(),

From e1974f1243fbf732b6435d8be77c2c20f2fcd5e4 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 31 Oct 2025 16:11:28 +0100
Subject: [PATCH 02/21] wip: some logging

---
 crates/pixi_command_dispatcher/src/source_build/mod.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/crates/pixi_command_dispatcher/src/source_build/mod.rs b/crates/pixi_command_dispatcher/src/source_build/mod.rs
index f90e5ae2d0..e674c102d4 100644
--- a/crates/pixi_command_dispatcher/src/source_build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build/mod.rs
@@ -125,6 +125,7 @@ impl SourceBuildSpec {
         name = "source-build",
         fields(
             source= %self.manifest_source,
+            build_source= ?self.build_source,
             package = %self.package,
         )
     )]
@@ -239,6 +240,8 @@ impl SourceBuildSpec {
             .await
             .map_err_with(SourceBuildError::Discovery)?;
 
+        tracing::error!("{:?}", discovered_backend.init_params);
+
         // Compute the package input hash for caching purposes.
         let package_build_input_hash = PackageBuildInputHash::from(discovered_backend.as_ref());
 

From 3370546e5efda587ee22e48d4ae46f0ee891c3e3 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Mon, 3 Nov 2025 14:56:48 +0100
Subject: [PATCH 03/21] fix: out-of-source caching

---
 crates/pixi_command_dispatcher/src/build/mod.rs     |  9 ++++++++-
 .../src/build_backend_metadata/mod.rs               | 11 +++++++++--
 .../src/command_dispatcher/mod.rs                   | 12 +++++++++++-
 .../pixi_command_dispatcher/src/source_build/mod.rs |  5 +++--
 .../src/source_build_cache_status/mod.rs            | 13 ++++++++-----
 5 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/crates/pixi_command_dispatcher/src/build/mod.rs b/crates/pixi_command_dispatcher/src/build/mod.rs
index 3318d74bd4..08039e4ed2 100644
--- a/crates/pixi_command_dispatcher/src/build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build/mod.rs
@@ -8,7 +8,6 @@ mod move_file;
 pub(crate) mod source_metadata_cache;
 mod work_dir_key;
 
-use core::fmt;
 use std::hash::{Hash, Hasher};
 
 use base64::{Engine, engine::general_purpose::URL_SAFE_NO_PAD};
@@ -67,6 +66,14 @@ impl SourceCodeLocation {
     pub fn source_code(&self) -> &PinnedSourceSpec {
         self.build_source.as_ref().unwrap_or(&self.manifest_source)
     }
+
+    pub fn as_source_and_alternative_root(&self) -> (&PinnedSourceSpec, Option<&PinnedSourceSpec>) {
+        if let Some(build_source) = &self.build_source {
+            (build_source, Some(&self.manifest_source))
+        } else {
+            (&self.manifest_source, None)
+        }
+    }
 }
 
 impl std::fmt::Display for SourceCodeLocation {
diff --git a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
index 0272e06fa2..0c46a51db0 100644
--- a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
@@ -114,7 +114,8 @@ impl BuildBackendMetadataSpec {
     ) -> Result<BuildBackendMetadata, CommandDispatcherError<BuildBackendMetadataError>> {
         // Ensure that the source is checked out before proceeding.
         let manifest_source_checkout = command_dispatcher
-            .checkout_pinned_source(self.manifest_source.clone())
+            // Never has an alternative root because we want to get the manifest
+            .checkout_pinned_source(self.manifest_source.clone(), None)
             .await
             .map_err_with(BuildBackendMetadataError::SourceCheckout)?;
 
@@ -131,11 +132,17 @@ impl BuildBackendMetadataSpec {
         let build_source_checkout = if let Some(pin_override) = &self.pin_override {
             Some(
                 command_dispatcher
-                    .checkout_pinned_source(pin_override.clone())
+                    // We use the pinned override directly
+                    .checkout_pinned_source(pin_override.clone(), None)
                     .await
                     .map_err_with(BuildBackendMetadataError::SourceCheckout)?,
             )
         } else if let Some(build_source) = &discovered_backend.init_params.build_source {
+            tracing::error!(
+                "build source = {:?}, manifest_path = {}",
+                build_source,
+                discovered_backend.init_params.manifest_path.display()
+            );
             Some(
                 command_dispatcher
                     .pin_and_checkout(
diff --git a/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs b/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
index 72962739c5..518bbb8481 100644
--- a/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
+++ b/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
@@ -627,12 +627,22 @@ impl CommandDispatcher {
     pub async fn checkout_pinned_source(
         &self,
         pinned_spec: PinnedSourceSpec,
+        alternative_root: Option<PinnedSourceSpec>,
     ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
         match pinned_spec {
             PinnedSourceSpec::Path(ref path) => {
+                let alternative_root_path = match alternative_root {
+                    Some(PinnedSourceSpec::Path(ref alt_path)) => Some(
+                        self.data
+                            .resolve_typed_path(alt_path.path.to_path(), None)
+                            .map_err(|e| CommandDispatcherError::Failed(e.into()))?,
+                    ),
+                    _ => None,
+                };
+
                 let source_path = self
                     .data
-                    .resolve_typed_path(path.path.to_path(), None)
+                    .resolve_typed_path(path.path.to_path(), alternative_root_path.as_deref())
                     .map_err(SourceCheckoutError::from)
                     .map_err(CommandDispatcherError::Failed)?;
                 Ok(SourceCheckout {
diff --git a/crates/pixi_command_dispatcher/src/source_build/mod.rs b/crates/pixi_command_dispatcher/src/source_build/mod.rs
index 2992f1d4cb..3f3c82a727 100644
--- a/crates/pixi_command_dispatcher/src/source_build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build/mod.rs
@@ -225,7 +225,8 @@ impl SourceBuildSpec {
 
         // Check out the source code.
         let manifest_source_checkout = command_dispatcher
-            .checkout_pinned_source(self.manifest_source.clone())
+            // This should be relative to the workspace, so we can pass in None
+            .checkout_pinned_source(self.manifest_source.clone(), None)
             .await
             .map_err_with(SourceBuildError::SourceCheckout)?;
 
@@ -265,7 +266,7 @@ impl SourceBuildSpec {
         // 3. Manifest source. Just assume that source is located at the same directory as the manifest.
         let build_source_dir = if let Some(pinned_build_source) = build_source {
             let build_source_checkout = command_dispatcher
-                .checkout_pinned_source(pinned_build_source)
+                .checkout_pinned_source(pinned_build_source, Some(self.manifest_source.clone()))
                 .await
                 .map_err_with(SourceBuildError::SourceCheckout)?;
             build_source_checkout.path
diff --git a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
index 6084d0b6ae..5edbc4e9db 100644
--- a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
@@ -201,7 +201,7 @@ impl SourceBuildCacheStatusSpec {
 
         // Determine if the package is out of date by checking the source
         let cached_build = match self
-            .check_source_out_of_date(command_dispatcher, cached_build, source.source_code())
+            .check_source_out_of_date(command_dispatcher, cached_build)
             .await?
         {
             CachedBuildStatus::UpToDate(cached_build) | CachedBuildStatus::New(cached_build) => {
@@ -308,7 +308,7 @@ impl SourceBuildCacheStatusSpec {
         &self,
         command_dispatcher: &CommandDispatcher,
         cached_build: CachedBuild,
-        source: &PinnedSourceSpec,
+        manifest_source: &PinnedSourceSpec,
     ) -> Result<CachedBuildStatus, CommandDispatcherError<SourceBuildCacheStatusError>> {
         let Some(source_info) = &cached_build.source else {
             return Ok(CachedBuildStatus::UpToDate(cached_build));
@@ -323,7 +323,8 @@ impl SourceBuildCacheStatusSpec {
 
         // Checkout the source for the package.
         let source_checkout = command_dispatcher
-            .checkout_pinned_source(source.clone())
+            // Manifest source so it is relative to the workspace
+            .checkout_pinned_source(manifest_source.clone(), None)
             .await
             .map_err_with(SourceBuildCacheStatusError::SourceCheckout)?;
 
@@ -361,7 +362,6 @@ impl SourceBuildCacheStatusSpec {
         &self,
         command_dispatcher: &CommandDispatcher,
         cached_build: CachedBuild,
-        source: &PinnedSourceSpec,
     ) -> Result<CachedBuildStatus, CommandDispatcherError<SourceBuildCacheStatusError>> {
         // If there are no source globs, we always consider the cached package
         // up-to-date.
@@ -369,9 +369,12 @@ impl SourceBuildCacheStatusSpec {
             return Ok(CachedBuildStatus::UpToDate(cached_build));
         };
 
+        // Convert into correct tuple
+        let (source, alternative_root) = self.source.as_source_and_alternative_root();
+
         // Checkout the source for the package.
         let source_checkout = command_dispatcher
-            .checkout_pinned_source(source.clone())
+            .checkout_pinned_source(source.clone(), alternative_root.cloned())
             .await
             .map_err_with(SourceBuildCacheStatusError::SourceCheckout)?;
 

From 4d5dfb102710bbbe888fa0a8b8e7e4f2891dc518 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Mon, 3 Nov 2025 15:41:39 +0100
Subject: [PATCH 04/21] feat: refactor to use SourceCodeLocation in more places

---
 crates/pixi_cli/src/build.rs                  |  6 +--
 .../pixi_command_dispatcher/src/build/mod.rs  | 16 +++++-
 .../src/build_backend_metadata/mod.rs         | 42 +++++++--------
 .../src/command_dispatcher/mod.rs             | 33 +++++++++---
 .../src/install_pixi/mod.rs                   | 10 ++--
 .../src/solve_conda/mod.rs                    |  2 +-
 .../solve_pixi/source_metadata_collector.rs   |  5 +-
 .../src/source_build/mod.rs                   | 52 +++++++++----------
 .../src/source_build_cache_status/mod.rs      | 10 ++--
 .../src/source_metadata/mod.rs                | 36 ++++++-------
 .../tests/integration/event_tree.rs           | 10 ++--
 crates/pixi_global/src/project/mod.rs         |  4 +-
 12 files changed, 123 insertions(+), 103 deletions(-)

diff --git a/crates/pixi_cli/src/build.rs b/crates/pixi_cli/src/build.rs
index fd647e3ce8..9ed5e43584 100644
--- a/crates/pixi_cli/src/build.rs
+++ b/crates/pixi_cli/src/build.rs
@@ -5,6 +5,7 @@ use indicatif::ProgressBar;
 use miette::{Context, IntoDiagnostic};
 use pixi_command_dispatcher::{
     BuildBackendMetadataSpec, BuildEnvironment, BuildProfile, CacheDirs, SourceBuildSpec,
+    build::SourceCodeLocation,
 };
 use pixi_config::ConfigCli;
 use pixi_core::WorkspaceLocator;
@@ -145,7 +146,7 @@ pub async fn execute(args: Args) -> miette::Result<()> {
 
     // Create the build backend metadata specification.
     let backend_metadata_spec = BuildBackendMetadataSpec {
-        manifest_source: manifest_source.clone(),
+        source: SourceCodeLocation::new(manifest_source.clone(), None),
         channels: channels.clone(),
         channel_config: channel_config.clone(),
         build_environment: build_environment.clone(),
@@ -183,8 +184,7 @@ pub async fn execute(args: Args) -> miette::Result<()> {
                 package,
                 // Build into a temporary directory first
                 output_directory: Some(temp_output_dir.path().to_path_buf()),
-                manifest_source: manifest_source.clone(),
-                build_source: None,
+                source: SourceCodeLocation::new(manifest_source.clone(), None),
                 channels: channels.clone(),
                 channel_config: channel_config.clone(),
                 build_environment: build_environment.clone(),
diff --git a/crates/pixi_command_dispatcher/src/build/mod.rs b/crates/pixi_command_dispatcher/src/build/mod.rs
index 08039e4ed2..4a81c758e5 100644
--- a/crates/pixi_command_dispatcher/src/build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build/mod.rs
@@ -67,6 +67,11 @@ impl SourceCodeLocation {
         self.build_source.as_ref().unwrap_or(&self.manifest_source)
     }
 
+    /// Get the optional explicit build source override.
+    pub fn build_source(&self) -> Option<&PinnedSourceSpec> {
+        self.build_source.as_ref()
+    }
+
     pub fn as_source_and_alternative_root(&self) -> (&PinnedSourceSpec, Option<&PinnedSourceSpec>) {
         if let Some(build_source) = &self.build_source {
             (build_source, Some(&self.manifest_source))
@@ -84,12 +89,21 @@ impl std::fmt::Display for SourceCodeLocation {
             self.manifest_source(),
             self.build_source
                 .as_ref()
-                .map(|build| format!("{}", build))
+                .map(|build| format!("{build}"))
                 .unwrap_or("undefined".to_string())
         )
     }
 }
 
+impl From<PinnedSourceSpec> for SourceCodeLocation {
+    fn from(manifest_source: PinnedSourceSpec) -> Self {
+        Self {
+            manifest_source,
+            build_source: None,
+        }
+    }
+}
+
 /// Try to deduce a name from a url.
 fn pretty_url_name(url: &Url) -> String {
     if let Some(last_segment) = url
diff --git a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
index 0c46a51db0..2c416a5198 100644
--- a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
@@ -25,7 +25,7 @@ use crate::{
     BuildEnvironment, CommandDispatcher, CommandDispatcherError, CommandDispatcherErrorResultExt,
     InstantiateBackendError, InstantiateBackendSpec, SourceCheckout, SourceCheckoutError,
     build::{
-        SourceRecordOrCheckout, WorkDirKey,
+        SourceCodeLocation, SourceRecordOrCheckout, WorkDirKey,
         source_metadata_cache::{self, CachedCondaMetadata, MetadataKind, SourceMetadataKey},
     },
 };
@@ -49,8 +49,8 @@ fn warn_once_per_backend(backend_name: &str) {
 /// particular source.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, serde::Serialize)]
 pub struct BuildBackendMetadataSpec {
-    /// The source specification where manifest is located at.
-    pub manifest_source: PinnedSourceSpec,
+    /// The manifest and optional build source location.
+    pub source: SourceCodeLocation,
 
     /// The channel configuration to use for the build backend.
     pub channel_config: ChannelConfig,
@@ -81,11 +81,8 @@ pub struct BuildBackendMetadataSpec {
 /// The metadata of a source checkout.
 #[derive(Debug)]
 pub struct BuildBackendMetadata {
-    /// The source checkout that the manifest was extracted from.
-    pub manifest_source: PinnedSourceSpec,
-
-    /// The source checkout from which we want to build package.
-    pub build_source: Option<PinnedSourceSpec>,
+    /// The manifest and optional build source location for this metadata.
+    pub source: SourceCodeLocation,
 
     /// The cache entry that contains the metadata acquired from the build
     /// backend.
@@ -103,7 +100,8 @@ impl BuildBackendMetadataSpec {
         skip_all,
         name="backend-metadata",
         fields(
-            source = %self.manifest_source,
+            manifest_source = %self.source.manifest_source(),
+            build_source = ?self.source.build_source(),
             platform = %self.build_environment.host_platform,
         )
     )]
@@ -112,10 +110,12 @@ impl BuildBackendMetadataSpec {
         command_dispatcher: CommandDispatcher,
         log_sink: UnboundedSender<String>,
     ) -> Result<BuildBackendMetadata, CommandDispatcherError<BuildBackendMetadataError>> {
+        let manifest_source = self.source.manifest_source().clone();
+
         // Ensure that the source is checked out before proceeding.
         let manifest_source_checkout = command_dispatcher
             // Never has an alternative root because we want to get the manifest
-            .checkout_pinned_source(self.manifest_source.clone(), None)
+            .checkout_pinned_source(&manifest_source)
             .await
             .map_err_with(BuildBackendMetadataError::SourceCheckout)?;
 
@@ -133,16 +133,11 @@ impl BuildBackendMetadataSpec {
             Some(
                 command_dispatcher
                     // We use the pinned override directly
-                    .checkout_pinned_source(pin_override.clone(), None)
+                    .checkout_pinned_source(pin_override)
                     .await
                     .map_err_with(BuildBackendMetadataError::SourceCheckout)?,
             )
         } else if let Some(build_source) = &discovered_backend.init_params.build_source {
-            tracing::error!(
-                "build source = {:?}, manifest_path = {}",
-                build_source,
-                discovered_backend.init_params.manifest_path.display()
-            );
             Some(
                 command_dispatcher
                     .pin_and_checkout(
@@ -174,6 +169,10 @@ impl BuildBackendMetadataSpec {
         } else {
             (manifest_source_checkout.clone(), None)
         };
+        let source_location = SourceCodeLocation::new(
+            manifest_source_checkout.pinned.clone(),
+            build_source.clone(),
+        );
 
         // Calculate the hash of the project model
         let additional_glob_hash = calculate_additional_glob_hash(
@@ -207,10 +206,9 @@ impl BuildBackendMetadataSpec {
             .await?
             {
                 return Ok(BuildBackendMetadata {
+                    source: source_location.clone(),
                     metadata,
                     cache_entry,
-                    manifest_source: manifest_source_checkout.pinned,
-                    build_source,
                 });
             }
         } else {
@@ -226,7 +224,7 @@ impl BuildBackendMetadataSpec {
             command_dispatcher
                 .instantiate_backend(InstantiateBackendSpec {
                     backend_spec: discovered_backend.backend_spec.clone().resolve(
-                        SourceAnchor::from(SourceSpec::from(self.manifest_source.clone())),
+                        SourceAnchor::from(SourceSpec::from(manifest_source.clone())),
                     ),
                     init_params: discovered_backend.init_params.clone(),
                     build_source_dir,
@@ -237,7 +235,6 @@ impl BuildBackendMetadataSpec {
                 .map_err_with(BuildBackendMetadataError::Initialize)?;
 
         // Call the conda_outputs method to get metadata.
-        let manifest_source = manifest_source_checkout.pinned.clone();
         if !backend.capabilities().provides_conda_outputs() {
             return Err(CommandDispatcherError::Failed(
                 BuildBackendMetadataError::BackendMissingCapabilities(
@@ -268,8 +265,7 @@ impl BuildBackendMetadataSpec {
             .map_err(CommandDispatcherError::Failed)?;
 
         Ok(BuildBackendMetadata {
-            manifest_source,
-            build_source,
+            source: source_location,
             metadata,
             cache_entry,
         })
@@ -487,7 +483,7 @@ impl BuildBackendMetadataSpec {
             build_environment: self.build_environment.clone(),
             build_variants: self.variants.clone().unwrap_or_default(),
             enabled_protocols: self.enabled_protocols.clone(),
-            pinned_source: self.manifest_source.clone(),
+            pinned_source: self.source.manifest_source().clone(),
         }
     }
 }
diff --git a/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs b/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
index 518bbb8481..84c6437ac9 100644
--- a/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
+++ b/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
@@ -35,7 +35,7 @@ use crate::{
     SourceBuildCacheEntry, SourceBuildCacheStatusError, SourceBuildCacheStatusSpec, SourceCheckout,
     SourceCheckoutError, SourceMetadata, SourceMetadataError, SourceMetadataSpec,
     backend_source_build::{BackendBuiltSource, BackendSourceBuildError, BackendSourceBuildSpec},
-    build::{BuildCache, source_metadata_cache::SourceMetadataCache},
+    build::{BuildCache, SourceCodeLocation, source_metadata_cache::SourceMetadataCache},
     cache_dirs::CacheDirs,
     discover_backend_cache::DiscoveryCache,
     install_pixi::{
@@ -625,14 +625,35 @@ impl CommandDispatcher {
     /// - For URL sources: Extracts the archive with the exact checksum
     ///   (unimplemented)
     pub async fn checkout_pinned_source(
+        &self,
+        pinned_spec: &PinnedSourceSpec,
+    ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
+        self.checkout_pinned_spec(pinned_spec.clone(), None).await
+    }
+
+    /// Checkout a source described by a [`SourceCodeLocation`], automatically
+    /// falling back to the manifest path when no dedicated build source is set.
+    ///
+    /// This is useful for the case where you want to checkout a source that is at
+    /// different location than the manifest, most obviously in an out-of-tree build.
+    pub async fn checkout_source_location(
+        &self,
+        source: &SourceCodeLocation,
+    ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
+        let (primary, alternative_root) = source.as_source_and_alternative_root();
+        self.checkout_pinned_spec(primary.clone(), alternative_root.cloned())
+            .await
+    }
+
+    async fn checkout_pinned_spec(
         &self,
         pinned_spec: PinnedSourceSpec,
         alternative_root: Option<PinnedSourceSpec>,
     ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
         match pinned_spec {
-            PinnedSourceSpec::Path(ref path) => {
-                let alternative_root_path = match alternative_root {
-                    Some(PinnedSourceSpec::Path(ref alt_path)) => Some(
+            PinnedSourceSpec::Path(path_spec) => {
+                let alternative_root_path = match alternative_root.as_ref() {
+                    Some(PinnedSourceSpec::Path(alt_path)) => Some(
                         self.data
                             .resolve_typed_path(alt_path.path.to_path(), None)
                             .map_err(|e| CommandDispatcherError::Failed(e.into()))?,
@@ -642,12 +663,12 @@ impl CommandDispatcher {
 
                 let source_path = self
                     .data
-                    .resolve_typed_path(path.path.to_path(), alternative_root_path.as_deref())
+                    .resolve_typed_path(path_spec.path.to_path(), alternative_root_path.as_deref())
                     .map_err(SourceCheckoutError::from)
                     .map_err(CommandDispatcherError::Failed)?;
                 Ok(SourceCheckout {
                     path: source_path,
-                    pinned: pinned_spec,
+                    pinned: PinnedSourceSpec::Path(path_spec),
                 })
             }
             PinnedSourceSpec::Git(git_spec) => self.checkout_pinned_git(git_spec).await,
diff --git a/crates/pixi_command_dispatcher/src/install_pixi/mod.rs b/crates/pixi_command_dispatcher/src/install_pixi/mod.rs
index beab694cc1..bd8b6bcb3a 100644
--- a/crates/pixi_command_dispatcher/src/install_pixi/mod.rs
+++ b/crates/pixi_command_dispatcher/src/install_pixi/mod.rs
@@ -23,8 +23,8 @@ use thiserror::Error;
 
 use crate::{
     BuildEnvironment, BuildProfile, CommandDispatcher, CommandDispatcherError,
-    CommandDispatcherErrorResultExt, SourceBuildError, SourceBuildSpec, executor::ExecutorFutures,
-    install_pixi::reporter::WrappingInstallReporter,
+    CommandDispatcherErrorResultExt, SourceBuildError, SourceBuildSpec, build::SourceCodeLocation,
+    executor::ExecutorFutures, install_pixi::reporter::WrappingInstallReporter,
 };
 
 #[derive(Debug, Clone, serde::Serialize)]
@@ -215,7 +215,10 @@ impl InstallPixiEnvironmentSpec {
             .contains(&source_record.package_record.name);
         let built_source = command_dispatcher
             .source_build(SourceBuildSpec {
-                manifest_source: source_record.manifest_source.clone(),
+                source: SourceCodeLocation::new(
+                    source_record.manifest_source.clone(),
+                    source_record.build_source.clone(),
+                ),
                 package: source_record.into(),
                 channel_config: self.channel_config.clone(),
                 channels: self.channels.clone(),
@@ -230,7 +233,6 @@ impl InstallPixiEnvironmentSpec {
                 force,
                 // When we install a pixi environment we always build in development mode.
                 build_profile: BuildProfile::Development,
-                build_source: source_record.build_source.clone(),
             })
             .await?;
 
diff --git a/crates/pixi_command_dispatcher/src/solve_conda/mod.rs b/crates/pixi_command_dispatcher/src/solve_conda/mod.rs
index 3617937f42..24fa98e753 100644
--- a/crates/pixi_command_dispatcher/src/solve_conda/mod.rs
+++ b/crates/pixi_command_dispatcher/src/solve_conda/mod.rs
@@ -156,7 +156,7 @@ impl SolveCondaEnvironmentSpec {
                         channel: None,
                     };
                     let mut record = record.clone();
-                    record.build_source = source_metadata.build_source.clone();
+                    record.build_source = source_metadata.source.build_source().cloned();
                     url_to_source_package.insert(url, (record, repodata_record));
                 }
             }
diff --git a/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs b/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs
index 9438ad1b8d..c6deb8db0a 100644
--- a/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs
+++ b/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs
@@ -15,6 +15,7 @@ use thiserror::Error;
 use crate::{
     BuildBackendMetadataSpec, BuildEnvironment, CommandDispatcher, CommandDispatcherError,
     SourceCheckoutError, SourceMetadataSpec,
+    build::SourceCodeLocation,
     executor::ExecutorFutures,
     source_metadata::{CycleEnvironment, SourceMetadata, SourceMetadataError},
 };
@@ -185,7 +186,7 @@ impl SourceMetadataCollector {
             .source_metadata(SourceMetadataSpec {
                 package: name.clone(),
                 backend_metadata: BuildBackendMetadataSpec {
-                    manifest_source: source.pinned,
+                    source: SourceCodeLocation::new(source.pinned, None),
                     channel_config: self.channel_config.clone(),
                     channels: self.channels.clone(),
                     build_environment: self.build_environment.clone(),
@@ -230,7 +231,7 @@ impl SourceMetadataCollector {
                         source_metadata.skipped_packages.clone(),
                     ),
                     name,
-                    pinned_source: Box::new(source_metadata.manifest_source.clone()),
+                    pinned_source: Box::new(source_metadata.source.manifest_source().clone()),
                 },
             ));
         }
diff --git a/crates/pixi_command_dispatcher/src/source_build/mod.rs b/crates/pixi_command_dispatcher/src/source_build/mod.rs
index 3f3c82a727..ee08dd4cb5 100644
--- a/crates/pixi_command_dispatcher/src/source_build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build/mod.rs
@@ -51,12 +51,8 @@ pub struct SourceBuildSpec {
     /// The source to build
     pub package: PackageIdentifier,
 
-    /// The location of the source code to build.
-    pub manifest_source: PinnedSourceSpec,
-
-    /// Optional source spec of sources which will be built.
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub build_source: Option<PinnedSourceSpec>,
+    /// The manifest and optional build source location.
+    pub source: SourceCodeLocation,
 
     /// The channel configuration to use when resolving metadata
     pub channel_config: ChannelConfig,
@@ -124,8 +120,8 @@ impl SourceBuildSpec {
         skip_all,
         name = "source-build",
         fields(
-            source= %self.manifest_source,
-            build_source= ?self.build_source,
+            manifest_source = %self.source.manifest_source(),
+            build_source = ?self.source.build_source(),
             package = %self.package,
         )
     )]
@@ -135,6 +131,8 @@ impl SourceBuildSpec {
         reporter: Option<Arc<dyn RunExportsReporter>>,
         log_sink: UnboundedSender<String>,
     ) -> Result<SourceBuildResult, CommandDispatcherError<SourceBuildError>> {
+        let manifest_source = self.source.manifest_source().clone();
+
         // If the output directory is not set, we want to use the build cache. Read the
         // build cache in that case.
         let (output_directory, build_cache) = if let Some(output_directory) =
@@ -148,10 +146,7 @@ impl SourceBuildSpec {
                 .source_build_cache_status(SourceBuildCacheStatusSpec {
                     package: self.package.clone(),
                     build_environment: self.build_environment.clone(),
-                    source: super::build::SourceCodeLocation::new(
-                        self.manifest_source.clone(),
-                        self.build_source.clone(),
-                    ),
+                    source: self.source.clone(),
                     channels: self.channels.clone(),
                     channel_config: self.channel_config.clone(),
                     enabled_protocols: self.enabled_protocols.clone(),
@@ -167,7 +162,7 @@ impl SourceBuildSpec {
                 if !self.force {
                     // If the build is up to date, we can return the cached build.
                     tracing::debug!(
-                        source = %self.manifest_source,
+                        source = %self.source.manifest_source(),
                         package = ?cached_build.record.package_record.name,
                         build = %cached_build.record.package_record.build,
                         output = %cached_build.record.file_name,
@@ -189,7 +184,7 @@ impl SourceBuildSpec {
                     self.package.name.as_normalized()
                 );
                 tracing::debug!(
-                    source = %self.manifest_source,
+                    source = %self.source.manifest_source(),
                     package = ?cached_build.record.package_record.name,
                     build = %cached_build.record.package_record.build,
                     output = %cached_build.record.file_name,
@@ -205,7 +200,7 @@ impl SourceBuildSpec {
             match &*build_cache.cached_build.lock().await {
                 CachedBuildStatus::Stale(existing) => {
                     tracing::debug!(
-                        source = %self.manifest_source,
+                        source = %self.source.manifest_source(),
                         package = ?existing.record.package_record.name,
                         build = %existing.record.package_record.build,
                         "rebuilding stale source build",
@@ -213,7 +208,7 @@ impl SourceBuildSpec {
                 }
                 CachedBuildStatus::Missing => {
                     tracing::debug!(
-                        source = %self.manifest_source,
+                        source = %self.source.manifest_source(),
                         "no cached source build; starting fresh build",
                     );
                 }
@@ -225,8 +220,7 @@ impl SourceBuildSpec {
 
         // Check out the source code.
         let manifest_source_checkout = command_dispatcher
-            // This should be relative to the workspace, so we can pass in None
-            .checkout_pinned_source(self.manifest_source.clone(), None)
+            .checkout_pinned_source(&manifest_source)
             .await
             .map_err_with(SourceBuildError::SourceCheckout)?;
 
@@ -250,7 +244,7 @@ impl SourceBuildSpec {
 
         // Ensure legacy lock entries that missed the git subdirectory pick it up from the
         // manifest so we check out the correct directory.
-        let mut build_source = self.build_source.clone();
+        let mut build_source = self.source.build_source().cloned();
         if let (Some(PinnedSourceSpec::Git(pinned_git)), Some(SourceLocationSpec::Git(git_spec))) = (
             build_source.as_mut(),
             discovered_backend.init_params.build_source.clone(),
@@ -265,8 +259,10 @@ impl SourceBuildSpec {
         // 2. Manifest package build. This can happen if package isn't added to the dependencies of manifest, so no pinning happens in that case.
         // 3. Manifest source. Just assume that source is located at the same directory as the manifest.
         let build_source_dir = if let Some(pinned_build_source) = build_source {
+            let build_location =
+                SourceCodeLocation::new(manifest_source.clone(), Some(pinned_build_source.clone()));
             let build_source_checkout = command_dispatcher
-                .checkout_pinned_source(pinned_build_source, Some(self.manifest_source.clone()))
+                .checkout_source_location(&build_location)
                 .await
                 .map_err_with(SourceBuildError::SourceCheckout)?;
             build_source_checkout.path
@@ -302,7 +298,7 @@ impl SourceBuildSpec {
             command_dispatcher
                 .instantiate_backend(InstantiateBackendSpec {
                     backend_spec: discovered_backend.backend_spec.clone().resolve(
-                        SourceAnchor::from(SourceSpec::from(self.manifest_source.clone())),
+                        SourceAnchor::from(SourceSpec::from(manifest_source.clone())),
                     ),
                     init_params: discovered_backend.init_params.clone(),
                     build_source_dir,
@@ -318,7 +314,7 @@ impl SourceBuildSpec {
             None => command_dispatcher.cache_dirs().working_dirs().join(
                 WorkDirKey {
                     source: SourceRecordOrCheckout::Record {
-                        pinned: self.manifest_source.clone(),
+                        pinned: manifest_source.clone(),
                         package_name: self.package.name.clone(),
                     },
                     host_platform: self.build_environment.host_platform,
@@ -328,7 +324,7 @@ impl SourceBuildSpec {
             ),
         };
         tracing::debug!(
-            source = %self.manifest_source,
+            source = %manifest_source,
             work_directory = %work_directory.display(),
             backend = backend.identifier(),
             "using work directory for source build",
@@ -344,7 +340,7 @@ impl SourceBuildSpec {
         }
 
         // Build the package using the v1 build method.
-        let source_for_logging = self.manifest_source.clone();
+        let source_for_logging = manifest_source.clone();
         let mut built_source = self
             .build_v1(
                 command_dispatcher,
@@ -497,7 +493,7 @@ impl SourceBuildSpec {
 
     /// Returns whether the package should be built in an editable mode.
     fn editable(&self) -> bool {
-        self.build_profile == BuildProfile::Development && self.manifest_source.is_mutable()
+        self.build_profile == BuildProfile::Development && self.source.source_code().is_mutable()
     }
 
     async fn build_v1(
@@ -509,7 +505,9 @@ impl SourceBuildSpec {
         reporter: Option<Arc<dyn RunExportsReporter>>,
         mut log_sink: UnboundedSender<String>,
     ) -> Result<BuiltPackage, CommandDispatcherError<SourceBuildError>> {
-        let source_anchor = SourceAnchor::from(SourceSpec::from(self.manifest_source.clone()));
+        let manifest_source = self.source.manifest_source().clone();
+
+        let source_anchor = SourceAnchor::from(SourceSpec::from(manifest_source.clone()));
         let host_platform = self.build_environment.host_platform;
         let build_platform = self.build_environment.build_platform;
 
@@ -732,7 +730,7 @@ impl SourceBuildSpec {
                 }),
                 backend,
                 package: self.package,
-                source: self.manifest_source,
+                source: manifest_source,
                 work_directory,
                 channels: self.channels,
                 channel_config: self.channel_config,
diff --git a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
index 5edbc4e9db..1b461044dd 100644
--- a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
@@ -136,7 +136,7 @@ impl SourceBuildCacheStatusSpec {
         };
         let (cached_build, build_cache_entry) = command_dispatcher
             .build_cache()
-            .entry(&self.source.manifest_source(), &build_input)
+            .entry(self.source.manifest_source(), &build_input)
             .await
             .map_err(SourceBuildCacheStatusError::BuildCache)
             .map_err(CommandDispatcherError::Failed)?;
@@ -323,8 +323,7 @@ impl SourceBuildCacheStatusSpec {
 
         // Checkout the source for the package.
         let source_checkout = command_dispatcher
-            // Manifest source so it is relative to the workspace
-            .checkout_pinned_source(manifest_source.clone(), None)
+            .checkout_pinned_source(manifest_source)
             .await
             .map_err_with(SourceBuildCacheStatusError::SourceCheckout)?;
 
@@ -369,12 +368,9 @@ impl SourceBuildCacheStatusSpec {
             return Ok(CachedBuildStatus::UpToDate(cached_build));
         };
 
-        // Convert into correct tuple
-        let (source, alternative_root) = self.source.as_source_and_alternative_root();
-
         // Checkout the source for the package.
         let source_checkout = command_dispatcher
-            .checkout_pinned_source(source.clone(), alternative_root.cloned())
+            .checkout_source_location(&self.source)
             .await
             .map_err_with(SourceBuildCacheStatusError::SourceCheckout)?;
 
diff --git a/crates/pixi_command_dispatcher/src/source_metadata/mod.rs b/crates/pixi_command_dispatcher/src/source_metadata/mod.rs
index cc6d01cfe0..9098600d2f 100644
--- a/crates/pixi_command_dispatcher/src/source_metadata/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_metadata/mod.rs
@@ -10,7 +10,7 @@ use futures::TryStreamExt;
 use itertools::{Either, Itertools};
 use miette::Diagnostic;
 use pixi_build_types::procedures::conda_outputs::CondaOutput;
-use pixi_record::{InputHash, PinnedSourceSpec, PixiRecord, SourceRecord};
+use pixi_record::{InputHash, PixiRecord, SourceRecord};
 use pixi_spec::{BinarySpec, PixiSpec, SourceAnchor, SourceSpec, SpecConversionError};
 use pixi_spec_containers::DependencyMap;
 use rattler_conda_types::{
@@ -26,7 +26,7 @@ use crate::{
     CommandDispatcherError, CommandDispatcherErrorResultExt, PixiEnvironmentSpec,
     SolvePixiEnvironmentError,
     build::{
-        Dependencies, DependenciesError, PixiRunExports, conversion,
+        Dependencies, DependenciesError, PixiRunExports, SourceCodeLocation, conversion,
         source_metadata_cache::MetadataKind,
     },
     executor::ExecutorFutures,
@@ -44,13 +44,8 @@ pub struct SourceMetadataSpec {
 /// The result of building a particular source record.
 #[derive(Debug, Clone)]
 pub struct SourceMetadata {
-    /// Information about the source checkout that was used to build the
-    /// package.
-    pub manifest_source: PinnedSourceSpec,
-
-    /// The optional location of where the actual source code is located,
-    /// this is used mainly for out-of-tree builds
-    pub build_source: Option<PinnedSourceSpec>,
+    /// Manifest and optional build source location for this metadata.
+    pub source: SourceCodeLocation,
 
     /// All the source records for this particular package.
     pub records: Vec<SourceRecord>,
@@ -64,7 +59,8 @@ impl SourceMetadataSpec {
         skip_all,
         name = "source-metadata",
         fields(
-            source= %self.backend_metadata.manifest_source,
+            manifest_source= %self.backend_metadata.source.manifest_source(),
+            build_source=?self.backend_metadata.source.build_source(),
             name = %self.package.as_source(),
             platform = %self.backend_metadata.build_environment.host_platform,
         )
@@ -84,26 +80,27 @@ impl SourceMetadataSpec {
 
         match &build_backend_metadata.metadata.metadata {
             MetadataKind::GetMetadata { packages } => {
+                let source_location = build_backend_metadata.source.clone();
                 // Convert the metadata to source records.
                 let records = conversion::package_metadata_to_source_records(
-                    &build_backend_metadata.manifest_source,
-                    build_backend_metadata.build_source.as_ref(),
+                    source_location.manifest_source(),
+                    source_location.build_source(),
                     packages,
                     &self.package,
                     &build_backend_metadata.metadata.input_hash,
                 );
 
                 Ok(SourceMetadata {
-                    manifest_source: build_backend_metadata.manifest_source.clone(),
+                    source: source_location,
                     records,
                     // As the GetMetadata kind returns all records at once and we don't solve them we can skip this.
                     skipped_packages: Default::default(),
-                    build_source: build_backend_metadata.build_source.clone(),
                 })
             }
             MetadataKind::Outputs { outputs } => {
                 let mut skipped_packages = vec![];
                 let mut futures = ExecutorFutures::new(command_dispatcher.executor());
+                let source_location = build_backend_metadata.source.clone();
                 for output in outputs {
                     if output.metadata.name != self.package {
                         skipped_packages.push(output.metadata.name.clone());
@@ -113,17 +110,15 @@ impl SourceMetadataSpec {
                         &command_dispatcher,
                         output,
                         build_backend_metadata.metadata.input_hash.clone(),
-                        build_backend_metadata.manifest_source.clone(),
-                        build_backend_metadata.build_source.clone(),
+                        source_location.clone(),
                         reporter.clone(),
                     ));
                 }
 
                 Ok(SourceMetadata {
-                    manifest_source: build_backend_metadata.manifest_source.clone(),
+                    source: source_location,
                     records: futures.try_collect().await?,
                     skipped_packages,
-                    build_source: build_backend_metadata.build_source.clone(),
                 })
             }
         }
@@ -134,10 +129,11 @@ impl SourceMetadataSpec {
         command_dispatcher: &CommandDispatcher,
         output: &CondaOutput,
         input_hash: Option<InputHash>,
-        manifest_source: PinnedSourceSpec,
-        build_source: Option<PinnedSourceSpec>,
+        source: SourceCodeLocation,
         reporter: Option<Arc<dyn RunExportsReporter>>,
     ) -> Result<SourceRecord, CommandDispatcherError<SourceMetadataError>> {
+        let manifest_source = source.manifest_source().clone();
+        let build_source = source.build_source().cloned();
         let source_anchor = SourceAnchor::from(SourceSpec::from(manifest_source.clone()));
 
         // Solve the build environment for the output.
diff --git a/crates/pixi_command_dispatcher/tests/integration/event_tree.rs b/crates/pixi_command_dispatcher/tests/integration/event_tree.rs
index 234df1521a..14a33ecbf3 100644
--- a/crates/pixi_command_dispatcher/tests/integration/event_tree.rs
+++ b/crates/pixi_command_dispatcher/tests/integration/event_tree.rs
@@ -130,7 +130,7 @@ impl EventTree {
                         format!(
                             "{} @ {}",
                             &spec.package.as_source(),
-                            spec.backend_metadata.manifest_source
+                            spec.backend_metadata.source
                         ),
                     );
                     builder.set_event_parent((*id).into(), *context);
@@ -146,7 +146,7 @@ impl EventTree {
                 }
                 Event::SourceMetadataFinished { .. } => {}
                 Event::BuildBackendMetadataQueued { id, context, spec } => {
-                    build_backend_metadata_label.insert(*id, spec.manifest_source.to_string());
+                    build_backend_metadata_label.insert(*id, spec.source.to_string());
                     builder.set_event_parent((*id).into(), *context);
                 }
                 Event::BuildBackendMetadataStarted { id } => {
@@ -162,11 +162,7 @@ impl EventTree {
                 Event::SourceBuildQueued { id, context, spec } => {
                     source_build_label.insert(
                         *id,
-                        format!(
-                            "{} @ {}",
-                            spec.package.name.as_source(),
-                            spec.manifest_source
-                        ),
+                        format!("{} @ {}", spec.package.name.as_source(), spec.source),
                     );
                     builder.set_event_parent((*id).into(), *context);
                 }
diff --git a/crates/pixi_global/src/project/mod.rs b/crates/pixi_global/src/project/mod.rs
index 7dd78704bd..6df70d0cf0 100644
--- a/crates/pixi_global/src/project/mod.rs
+++ b/crates/pixi_global/src/project/mod.rs
@@ -23,7 +23,7 @@ pub use parsed_manifest::{ExposedName, ParsedEnvironment, ParsedManifest};
 use pixi_build_discovery::EnabledProtocols;
 use pixi_command_dispatcher::{
     BuildBackendMetadataSpec, BuildEnvironment, CommandDispatcher, InstallPixiEnvironmentSpec,
-    Limits, PixiEnvironmentSpec,
+    Limits, PixiEnvironmentSpec, build::SourceCodeLocation,
 };
 use pixi_config::{Config, RunPostLinkScripts, default_channel_config, pixi_home};
 use pixi_consts::consts::{self};
@@ -1380,7 +1380,7 @@ impl Project {
 
         // Create the metadata spec
         let metadata_spec = BuildBackendMetadataSpec {
-            manifest_source: pinned_source_spec,
+            source: SourceCodeLocation::new(pinned_source_spec, None),
             channel_config: self.global_channel_config().clone(),
             channels: self
                 .config()

From 8ee563095aa6d5ece0f9fe15bfaddf947d3537ce Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Mon, 3 Nov 2025 16:36:25 +0100
Subject: [PATCH 05/21] feat: remove from and update snap

---
 crates/pixi_command_dispatcher/src/build/mod.rs          | 9 ---------
 .../tests/integration/snapshots/integration__cycle.snap  | 8 ++++----
 2 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/crates/pixi_command_dispatcher/src/build/mod.rs b/crates/pixi_command_dispatcher/src/build/mod.rs
index 4a81c758e5..0555467701 100644
--- a/crates/pixi_command_dispatcher/src/build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build/mod.rs
@@ -95,15 +95,6 @@ impl std::fmt::Display for SourceCodeLocation {
     }
 }
 
-impl From<PinnedSourceSpec> for SourceCodeLocation {
-    fn from(manifest_source: PinnedSourceSpec) -> Self {
-        Self {
-            manifest_source,
-            build_source: None,
-        }
-    }
-}
-
 /// Try to deduce a name from a url.
 fn pretty_url_name(url: &Url) -> String {
     if let Some(last_segment) = url
diff --git a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap
index b5f8bf5d7f..02e20f8a35 100644
--- a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap
+++ b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap
@@ -16,8 +16,8 @@ ERROR:
 
 TRACE:
 Pixi solve (package_a)
-└── Source metadata (package_a @ package_a)
-    ├── Build backend metadata (package_a)
+└── Source metadata (package_a @ (manifest-src: package_a, build-src: undefined))
+    ├── Build backend metadata ((manifest-src: package_a, build-src: undefined))
     └── Pixi solve (package_b)
-        └── Source metadata (package_b @ package_b)
-            └── Build backend metadata (package_b)
+        └── Source metadata (package_b @ (manifest-src: package_b, build-src: undefined))
+            └── Build backend metadata ((manifest-src: package_b, build-src: undefined))

From e60d90d663555186cc2cdf4131341a574ec14100 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Mon, 3 Nov 2025 22:27:14 +0100
Subject: [PATCH 06/21] snapshot

---
 .../snapshots/integration__simple_test.snap            | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap
index 635a5822d4..e5a6313312 100644
--- a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap
+++ b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap
@@ -4,16 +4,16 @@ expression: event_tree.to_string()
 ---
 Pixi solve (foobar-desktop)
 ├── Git Checkout (https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
-├── Source metadata (foobar-desktop @ https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
-│   └── Build backend metadata (https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
+├── Source metadata (foobar-desktop @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
+│   └── Build backend metadata ((manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
 │       └── Instantiate tool environment (pixi-build-rattler-build)
 │           ├── Pixi solve (pixi-build-rattler-build)
 │           │   └── Conda solve #0
 │           └── Pixi install (pixi-build-rattler-build)
-├── Source metadata (foobar @ https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
+├── Source metadata (foobar @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
 └── Conda solve #1
 Pixi install (test-env)
-├── Source build (foobar @ https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
+├── Source build (foobar @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
 │   └── Backend source build (foobar)
-└── Source build (foobar-desktop @ https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
+└── Source build (foobar-desktop @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
     └── Backend source build (foobar-desktop)

From 6a0cff83cdc2a25e08c23533c141ee6c451ba96b Mon Sep 17 00:00:00 2001
From: Bas Zalmstra <4995967+baszalmstra@users.noreply.github.com>
Date: Tue, 4 Nov 2025 14:37:54 +0100
Subject: [PATCH 07/21] fix: always make build_source relative to workspace

---
 .../pixi_build_discovery/src/backend_spec.rs  |  14 +-
 crates/pixi_cli/src/build.rs                  |   4 +-
 .../src/build/dependencies.rs                 |  10 +-
 .../src/build_backend_metadata/mod.rs         | 119 ++---
 .../command_dispatcher/instantiate_backend.rs |  52 ++-
 .../src/command_dispatcher/mod.rs             |  63 +--
 .../src/instantiate_tool_env/mod.rs           |   2 +-
 .../src/solve_pixi/mod.rs                     |   9 +-
 .../solve_pixi/source_metadata_collector.rs   |  28 +-
 .../src/source_build/mod.rs                   |  74 ++-
 .../src/source_build_cache_status/mod.rs      |   8 +-
 .../src/source_metadata/mod.rs                |  10 +-
 .../tests/integration/event_tree.rs           |   4 +-
 .../snapshots/integration__cycle.snap         |   8 +-
 .../snapshots/integration__simple_test.snap   |   6 +-
 .../src/lock_file/satisfiability/mod.rs       |   5 +-
 crates/pixi_core/src/lock_file/update.rs      |   2 +-
 crates/pixi_global/src/common.rs              |   4 +-
 crates/pixi_global/src/project/mod.rs         |   8 +-
 crates/pixi_record/src/pinned_source.rs       | 429 ++++++++++++++++++
 crates/pixi_spec/src/source_anchor.rs         |  63 ++-
 21 files changed, 656 insertions(+), 266 deletions(-)

diff --git a/crates/pixi_build_discovery/src/backend_spec.rs b/crates/pixi_build_discovery/src/backend_spec.rs
index e2889173a3..6bcffd4969 100644
--- a/crates/pixi_build_discovery/src/backend_spec.rs
+++ b/crates/pixi_build_discovery/src/backend_spec.rs
@@ -1,4 +1,4 @@
-use pixi_spec::{BinarySpec, PixiSpec, SourceAnchor};
+use pixi_spec::{BinarySpec, PixiSpec, SourceAnchor, SourceSpec};
 use pixi_spec_containers::DependencyMap;
 use rattler_conda_types::ChannelUrl;
 /// Describes how a backend should be instantiated.
@@ -45,8 +45,10 @@ impl JsonRpcBackendSpec {
                         let maybe_source_spec = env_spec.requirement.1.try_into_source_spec();
                         let pixi_spec = match maybe_source_spec {
                             Ok(source_spec) => {
-                                let resolved_spec = source_anchor.resolve(source_spec);
-                                PixiSpec::from(resolved_spec)
+                                let resolved_spec = source_anchor.resolve(source_spec.location);
+                                PixiSpec::from(SourceSpec {
+                                    location: resolved_spec,
+                                })
                             }
                             Err(pixi_spec) => pixi_spec,
                         };
@@ -133,8 +135,10 @@ impl EnvironmentSpec {
         let maybe_source_spec = self.requirement.1.try_into_source_spec();
         let pixi_spec = match maybe_source_spec {
             Ok(source_spec) => {
-                let resolved_spec = source_anchor.resolve(source_spec);
-                PixiSpec::from(resolved_spec)
+                let resolved_spec = source_anchor.resolve(source_spec.location);
+                PixiSpec::from(SourceSpec {
+                    location: resolved_spec,
+                })
             }
             Err(pixi_spec) => pixi_spec,
         };
diff --git a/crates/pixi_cli/src/build.rs b/crates/pixi_cli/src/build.rs
index 9ed5e43584..6ed8f68503 100644
--- a/crates/pixi_cli/src/build.rs
+++ b/crates/pixi_cli/src/build.rs
@@ -146,14 +146,14 @@ pub async fn execute(args: Args) -> miette::Result<()> {
 
     // Create the build backend metadata specification.
     let backend_metadata_spec = BuildBackendMetadataSpec {
-        source: SourceCodeLocation::new(manifest_source.clone(), None),
+        manifest_source: manifest_source.clone(),
+        preferred_build_source: None,
         channels: channels.clone(),
         channel_config: channel_config.clone(),
         build_environment: build_environment.clone(),
         variants: Some(variants.clone()),
         variant_files: Some(variant_files.clone()),
         enabled_protocols: Default::default(),
-        pin_override: None,
     };
     let backend_metadata = command_dispatcher
         .build_backend_metadata(backend_metadata_spec.clone())
diff --git a/crates/pixi_command_dispatcher/src/build/dependencies.rs b/crates/pixi_command_dispatcher/src/build/dependencies.rs
index abfea9c4d4..4c137987a2 100644
--- a/crates/pixi_command_dispatcher/src/build/dependencies.rs
+++ b/crates/pixi_command_dispatcher/src/build/dependencies.rs
@@ -8,7 +8,7 @@ use pixi_build_types::{
     },
 };
 use pixi_record::PixiRecord;
-use pixi_spec::{BinarySpec, DetailedSpec, PixiSpec, SourceAnchor, UrlBinarySpec};
+use pixi_spec::{BinarySpec, DetailedSpec, PixiSpec, SourceAnchor, SourceSpec, UrlBinarySpec};
 use pixi_spec_containers::DependencyMap;
 use rattler_conda_types::{
     InvalidPackageNameError, MatchSpec, NamedChannelOrUrl, NamelessMatchSpec, PackageName,
@@ -95,12 +95,12 @@ impl Dependencies {
             })?;
             match conversion::from_package_spec_v1(depend.spec.clone()).into_source_or_binary() {
                 Either::Left(source) => {
-                    let source = if let Some(anchor) = &source_anchor {
-                        anchor.resolve(source)
+                    let location = if let Some(anchor) = &source_anchor {
+                        anchor.resolve(source.location)
                     } else {
-                        source
+                        source.location
                     };
-                    dependencies.insert(name, PixiSpec::from(source).into());
+                    dependencies.insert(name, PixiSpec::from(SourceSpec { location }).into());
                 }
                 Either::Right(binary) => {
                     dependencies.insert(name, PixiSpec::from(binary).into());
diff --git a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
index 2c416a5198..cc5593b078 100644
--- a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
@@ -49,8 +49,18 @@ fn warn_once_per_backend(backend_name: &str) {
 /// particular source.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, serde::Serialize)]
 pub struct BuildBackendMetadataSpec {
-    /// The manifest and optional build source location.
-    pub source: SourceCodeLocation,
+    /// The location that refers to where the manifest is stored.
+    pub manifest_source: PinnedSourceSpec,
+
+    /// The optional pinned location of the source code. If not provide the
+    /// location in the manifest is resolved.
+    ///
+    /// This is passed as a hint. If the [`SourceSpec`] in the discovered
+    /// manifest does not match with the pinned source provided here, the one
+    /// in the manifest takes precedence and it is reresolved.
+    ///
+    /// See [`PinnedSourceSpec::matches_source_spec`] how the matching is done.
+    pub preferred_build_source: Option<PinnedSourceSpec>,
 
     /// The channel configuration to use for the build backend.
     pub channel_config: ChannelConfig,
@@ -71,11 +81,6 @@ pub struct BuildBackendMetadataSpec {
     /// The protocols that are enabled for this source
     #[serde(skip_serializing_if = "crate::is_default")]
     pub enabled_protocols: EnabledProtocols,
-
-    /// Optional override for the pinned build source of the current package.
-    /// When set, this takes precedence over any discovered build_source.
-    #[serde(skip)]
-    pub pin_override: Option<PinnedSourceSpec>,
 }
 
 /// The metadata of a source checkout.
@@ -100,8 +105,8 @@ impl BuildBackendMetadataSpec {
         skip_all,
         name="backend-metadata",
         fields(
-            manifest_source = %self.source.manifest_source(),
-            build_source = ?self.source.build_source(),
+            manifest_source = ?self.manifest_source,
+            build_source = ?self.preferred_build_source,
             platform = %self.build_environment.host_platform,
         )
     )]
@@ -110,12 +115,10 @@ impl BuildBackendMetadataSpec {
         command_dispatcher: CommandDispatcher,
         log_sink: UnboundedSender<String>,
     ) -> Result<BuildBackendMetadata, CommandDispatcherError<BuildBackendMetadataError>> {
-        let manifest_source = self.source.manifest_source().clone();
-
         // Ensure that the source is checked out before proceeding.
         let manifest_source_checkout = command_dispatcher
             // Never has an alternative root because we want to get the manifest
-            .checkout_pinned_source(&manifest_source)
+            .checkout_pinned_source(self.manifest_source.clone())
             .await
             .map_err_with(BuildBackendMetadataError::SourceCheckout)?;
 
@@ -129,38 +132,36 @@ impl BuildBackendMetadataSpec {
             .await
             .map_err_with(BuildBackendMetadataError::Discovery)?;
 
-        let build_source_checkout = if let Some(pin_override) = &self.pin_override {
-            Some(
-                command_dispatcher
-                    // We use the pinned override directly
-                    .checkout_pinned_source(pin_override)
-                    .await
-                    .map_err_with(BuildBackendMetadataError::SourceCheckout)?,
-            )
-        } else if let Some(build_source) = &discovered_backend.init_params.build_source {
-            Some(
-                command_dispatcher
-                    .pin_and_checkout(
-                        build_source.clone(),
+        // Determine the location of the source to build from.
+        let manifest_source_anchor =
+            SourceAnchor::from(SourceSpec::from(self.manifest_source.clone()));
+        let build_source_checkout = match &discovered_backend.init_params.build_source {
+            None => None,
+            Some(spec) => {
+                // An out of tree source is provided. Resolve it against the manifest source.
+                let resolved_location = manifest_source_anchor.resolve(spec.clone());
+                let resolved_source_build_spec = SourceSpec {
+                    location: resolved_location.clone(),
+                };
+
+                // Check if we have a preferred build source that matches this same location
+                match &self.preferred_build_source {
+                    Some(pinned) if pinned.matches_source_spec(&resolved_source_build_spec) => {
                         Some(
-                            discovered_backend
-                                .init_params
-                                .manifest_path
-                                .parent()
-                                .ok_or_else(|| {
-                                    SourceCheckoutError::ParentDir(
-                                        discovered_backend.init_params.manifest_path.clone(),
-                                    )
-                                })
-                                .map_err(BuildBackendMetadataError::SourceCheckout)
-                                .map_err(CommandDispatcherError::Failed)?,
-                        ),
-                    )
-                    .await
-                    .map_err_with(BuildBackendMetadataError::SourceCheckout)?,
-            )
-        } else {
-            None
+                            command_dispatcher
+                                .checkout_pinned_source(pinned.clone())
+                                .await
+                                .map_err_with(BuildBackendMetadataError::SourceCheckout)?,
+                        )
+                    }
+                    _ => Some(
+                        command_dispatcher
+                            .pin_and_checkout(resolved_location)
+                            .await
+                            .map_err_with(BuildBackendMetadataError::SourceCheckout)?,
+                    ),
+                }
+            }
         };
 
         let (build_source_checkout, build_source) = if let Some(checkout) = build_source_checkout {
@@ -220,19 +221,23 @@ impl BuildBackendMetadataSpec {
 
         let build_source_dir = build_source_checkout.path.clone();
         // Instantiate the backend with the discovered information.
-        let backend =
-            command_dispatcher
-                .instantiate_backend(InstantiateBackendSpec {
-                    backend_spec: discovered_backend.backend_spec.clone().resolve(
-                        SourceAnchor::from(SourceSpec::from(manifest_source.clone())),
-                    ),
-                    init_params: discovered_backend.init_params.clone(),
-                    build_source_dir,
-                    channel_config: self.channel_config.clone(),
-                    enabled_protocols: self.enabled_protocols.clone(),
-                })
-                .await
-                .map_err_with(BuildBackendMetadataError::Initialize)?;
+        let backend = command_dispatcher
+            .instantiate_backend(InstantiateBackendSpec {
+                backend_spec: discovered_backend
+                    .backend_spec
+                    .clone()
+                    .resolve(manifest_source_anchor),
+                build_source_dir,
+                channel_config: self.channel_config.clone(),
+                enabled_protocols: self.enabled_protocols.clone(),
+                workspace_root: discovered_backend.init_params.workspace_root.clone(),
+                manifest_path: discovered_backend.init_params.manifest_path.clone(),
+                project_model: discovered_backend.init_params.project_model.clone(),
+                configuration: discovered_backend.init_params.configuration.clone(),
+                target_configuration: discovered_backend.init_params.target_configuration.clone(),
+            })
+            .await
+            .map_err_with(BuildBackendMetadataError::Initialize)?;
 
         // Call the conda_outputs method to get metadata.
         if !backend.capabilities().provides_conda_outputs() {
@@ -483,7 +488,7 @@ impl BuildBackendMetadataSpec {
             build_environment: self.build_environment.clone(),
             build_variants: self.variants.clone().unwrap_or_default(),
             enabled_protocols: self.enabled_protocols.clone(),
-            pinned_source: self.source.manifest_source().clone(),
+            pinned_source: self.manifest_source.clone(),
         }
     }
 }
diff --git a/crates/pixi_command_dispatcher/src/command_dispatcher/instantiate_backend.rs b/crates/pixi_command_dispatcher/src/command_dispatcher/instantiate_backend.rs
index 07444fb4ba..c373921484 100644
--- a/crates/pixi_command_dispatcher/src/command_dispatcher/instantiate_backend.rs
+++ b/crates/pixi_command_dispatcher/src/command_dispatcher/instantiate_backend.rs
@@ -1,15 +1,16 @@
 use std::path::PathBuf;
 
 use miette::Diagnostic;
-use pixi_build_discovery::{
-    BackendInitializationParams, BackendSpec, CommandSpec, EnabledProtocols,
-};
+use ordermap::OrderMap;
+use pixi_build_discovery::{BackendSpec, CommandSpec, EnabledProtocols};
 use pixi_build_frontend::{
     Backend, BackendOverride, json_rpc,
     json_rpc::{CommunicationError, JsonRpcBackend},
     tool::{IsolatedTool, SystemTool, Tool},
 };
-use pixi_build_types::{PixiBuildApiVersion, procedures::initialize::InitializeParams};
+use pixi_build_types::{
+    PixiBuildApiVersion, ProjectModelV1, TargetSelectorV1, procedures::initialize::InitializeParams,
+};
 use pixi_spec::SpecConversionError;
 use rattler_conda_types::ChannelConfig;
 use rattler_shell::{
@@ -33,8 +34,20 @@ pub struct InstantiateBackendSpec {
     /// The backend specification
     pub backend_spec: BackendSpec,
 
-    /// The parameters to initialize the backend with
-    pub init_params: BackendInitializationParams,
+    /// The root directory of the workspace.
+    pub workspace_root: PathBuf,
+
+    /// The absolute path of the discovered manifest
+    pub manifest_path: PathBuf,
+
+    /// Optionally, the manifest of the discovered package.
+    pub project_model: Option<ProjectModelV1>,
+
+    /// Additional configuration that applies to the backend.
+    pub configuration: Option<serde_json::Value>,
+
+    /// Targets that apply to the backend.
+    pub target_configuration: Option<OrderMap<TargetSelectorV1, serde_json::Value>>,
 
     /// The source directory to use for the backend
     pub build_source_dir: PathBuf,
@@ -55,15 +68,13 @@ impl CommandDispatcher {
     ) -> Result<Backend, CommandDispatcherError<InstantiateBackendError>> {
         let BackendSpec::JsonRpc(backend_spec) = spec.backend_spec;
 
-        let source_dir = spec.build_source_dir;
-
         // Canonicalize the source_dir to ensure it's a fully resolved absolute path
         // without any relative components like ".." or "."
-        let source_dir = dunce::canonicalize(&source_dir).map_err(|e| {
+        let source_dir = dunce::canonicalize(&spec.build_source_dir).map_err(|e| {
             CommandDispatcherError::Failed(InstantiateBackendError::SpecConversionError(
                 SpecConversionError::InvalidPath(format!(
                     "failed to canonicalize source directory '{}': {}",
-                    source_dir.display(),
+                    spec.build_source_dir.display(),
                     e
                 )),
             ))
@@ -79,13 +90,13 @@ impl CommandDispatcher {
                 if let Some(in_mem) = backend {
                     let memory = in_mem
                         .initialize(InitializeParams {
-                            manifest_path: spec.init_params.manifest_path,
+                            manifest_path: spec.manifest_path,
                             source_dir: Some(source_dir),
-                            workspace_root: Some(spec.init_params.workspace_root),
+                            workspace_root: Some(spec.workspace_root),
                             cache_directory: Some(self.cache_dirs().root().clone()),
-                            project_model: spec.init_params.project_model.map(Into::into),
-                            configuration: spec.init_params.configuration,
-                            target_configuration: spec.init_params.target_configuration,
+                            project_model: spec.project_model.map(Into::into),
+                            configuration: spec.configuration,
+                            target_configuration: spec.target_configuration,
                         })
                         .map_err(InstantiateBackendError::InMemoryError)
                         .map_err(CommandDispatcherError::Failed)?;
@@ -165,7 +176,6 @@ impl CommandDispatcher {
         // Make sure that the project model is compatible with the API version.
         if !api_version.supports_name_none()
             && spec
-                .init_params
                 .project_model
                 .as_ref()
                 .is_some_and(|p| p.name.is_none())
@@ -177,11 +187,11 @@ impl CommandDispatcher {
 
         JsonRpcBackend::setup(
             source_dir,
-            spec.init_params.manifest_path,
-            spec.init_params.workspace_root,
-            spec.init_params.project_model,
-            spec.init_params.configuration,
-            spec.init_params.target_configuration,
+            spec.manifest_path,
+            spec.workspace_root,
+            spec.project_model,
+            spec.configuration,
+            spec.target_configuration,
             Some(self.cache_dirs().root().clone()),
             tool,
         )
diff --git a/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs b/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
index 84c6437ac9..c5802ed714 100644
--- a/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
+++ b/crates/pixi_command_dispatcher/src/command_dispatcher/mod.rs
@@ -35,7 +35,7 @@ use crate::{
     SourceBuildCacheEntry, SourceBuildCacheStatusError, SourceBuildCacheStatusSpec, SourceCheckout,
     SourceCheckoutError, SourceMetadata, SourceMetadataError, SourceMetadataSpec,
     backend_source_build::{BackendBuiltSource, BackendSourceBuildError, BackendSourceBuildSpec},
-    build::{BuildCache, SourceCodeLocation, source_metadata_cache::SourceMetadataCache},
+    build::{BuildCache, source_metadata_cache::SourceMetadataCache},
     cache_dirs::CacheDirs,
     discover_backend_cache::DiscoveryCache,
     install_pixi::{
@@ -591,7 +591,6 @@ impl CommandDispatcher {
     pub async fn pin_and_checkout(
         &self,
         source_location_spec: SourceLocationSpec,
-        alternative_root: Option<&Path>,
     ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
         match source_location_spec {
             SourceLocationSpec::Url(url) => {
@@ -600,7 +599,7 @@ impl CommandDispatcher {
             SourceLocationSpec::Path(path) => {
                 let source_path = self
                     .data
-                    .resolve_typed_path(path.path.to_path(), alternative_root)
+                    .resolve_typed_path(path.path.to_path())
                     .map_err(SourceCheckoutError::from)
                     .map_err(CommandDispatcherError::Failed)?;
                 Ok(SourceCheckout {
@@ -625,50 +624,19 @@ impl CommandDispatcher {
     /// - For URL sources: Extracts the archive with the exact checksum
     ///   (unimplemented)
     pub async fn checkout_pinned_source(
-        &self,
-        pinned_spec: &PinnedSourceSpec,
-    ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
-        self.checkout_pinned_spec(pinned_spec.clone(), None).await
-    }
-
-    /// Checkout a source described by a [`SourceCodeLocation`], automatically
-    /// falling back to the manifest path when no dedicated build source is set.
-    ///
-    /// This is useful for the case where you want to checkout a source that is at
-    /// different location than the manifest, most obviously in an out-of-tree build.
-    pub async fn checkout_source_location(
-        &self,
-        source: &SourceCodeLocation,
-    ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
-        let (primary, alternative_root) = source.as_source_and_alternative_root();
-        self.checkout_pinned_spec(primary.clone(), alternative_root.cloned())
-            .await
-    }
-
-    async fn checkout_pinned_spec(
         &self,
         pinned_spec: PinnedSourceSpec,
-        alternative_root: Option<PinnedSourceSpec>,
     ) -> Result<SourceCheckout, CommandDispatcherError<SourceCheckoutError>> {
         match pinned_spec {
-            PinnedSourceSpec::Path(path_spec) => {
-                let alternative_root_path = match alternative_root.as_ref() {
-                    Some(PinnedSourceSpec::Path(alt_path)) => Some(
-                        self.data
-                            .resolve_typed_path(alt_path.path.to_path(), None)
-                            .map_err(|e| CommandDispatcherError::Failed(e.into()))?,
-                    ),
-                    _ => None,
-                };
-
+            PinnedSourceSpec::Path(ref path_spec) => {
                 let source_path = self
                     .data
-                    .resolve_typed_path(path_spec.path.to_path(), alternative_root_path.as_deref())
+                    .resolve_typed_path(path_spec.path.to_path())
                     .map_err(SourceCheckoutError::from)
                     .map_err(CommandDispatcherError::Failed)?;
                 Ok(SourceCheckout {
                     path: source_path,
-                    pinned: PinnedSourceSpec::Path(path_spec),
+                    pinned: pinned_spec,
                 })
             }
             PinnedSourceSpec::Git(git_spec) => self.checkout_pinned_git(git_spec).await,
@@ -698,11 +666,7 @@ impl CommandDispatcherData {
     ///
     /// This function does not check if the path exists and also does not follow
     /// symlinks.
-    fn resolve_typed_path(
-        &self,
-        path_spec: Utf8TypedPath,
-        alternative_root: Option<&Path>,
-    ) -> Result<PathBuf, InvalidPathError> {
+    fn resolve_typed_path(&self, path_spec: Utf8TypedPath) -> Result<PathBuf, InvalidPathError> {
         if path_spec.is_absolute() {
             Ok(Path::new(path_spec.as_str()).to_path_buf())
         } else if let Ok(user_path) = path_spec.strip_prefix("~/") {
@@ -712,20 +676,7 @@ impl CommandDispatcherData {
             debug_assert!(home_dir.is_absolute());
             normalize_absolute_path(&home_dir.join(Path::new(user_path.as_str())))
         } else {
-            let root_dir = match alternative_root {
-                Some(root_path) => {
-                    debug_assert!(
-                        root_path.is_absolute(),
-                        "alternative_root must be absolute, got: {root_path:?}"
-                    );
-                    debug_assert!(
-                        !root_path.is_file(),
-                        "alternative_root should be a directory, not a file: {root_path:?}"
-                    );
-                    root_path
-                }
-                None => self.root_dir.as_path(),
-            };
+            let root_dir = self.root_dir.as_path();
             let native_path = Path::new(path_spec.as_str());
             debug_assert!(root_dir.is_absolute());
             normalize_absolute_path(&root_dir.join(native_path))
diff --git a/crates/pixi_command_dispatcher/src/instantiate_tool_env/mod.rs b/crates/pixi_command_dispatcher/src/instantiate_tool_env/mod.rs
index 3e83bd31e8..0553e60428 100644
--- a/crates/pixi_command_dispatcher/src/instantiate_tool_env/mod.rs
+++ b/crates/pixi_command_dispatcher/src/instantiate_tool_env/mod.rs
@@ -216,7 +216,7 @@ impl InstantiateToolEnvironmentSpec {
                 variants: self.variants.clone(),
                 variant_files: self.variant_files.clone(),
                 strategy: SolveStrategy::default(),
-                pin_overrides: BTreeMap::new(),
+                preferred_build_source: BTreeMap::new(),
             })
             .await
             .map_err_with(Box::new)
diff --git a/crates/pixi_command_dispatcher/src/solve_pixi/mod.rs b/crates/pixi_command_dispatcher/src/solve_pixi/mod.rs
index af8f645bd5..06a47339e8 100644
--- a/crates/pixi_command_dispatcher/src/solve_pixi/mod.rs
+++ b/crates/pixi_command_dispatcher/src/solve_pixi/mod.rs
@@ -89,9 +89,10 @@ pub struct PixiEnvironmentSpec {
 
     /// Optional override for a specific packages: use this pinned
     /// source for checkout and as the `package_build_source` instead
-    /// of pinning anew.
+    /// of recomputing the pinned location.
     #[serde(skip)]
-    pub pin_overrides: BTreeMap<rattler_conda_types::PackageName, pixi_record::PinnedSourceSpec>,
+    pub preferred_build_source:
+        BTreeMap<rattler_conda_types::PackageName, pixi_record::PinnedSourceSpec>,
 }
 
 impl Default for PixiEnvironmentSpec {
@@ -110,7 +111,7 @@ impl Default for PixiEnvironmentSpec {
             variants: None,
             variant_files: None,
             enabled_protocols: EnabledProtocols::default(),
-            pin_overrides: BTreeMap::new(),
+            preferred_build_source: BTreeMap::new(),
         }
     }
 }
@@ -148,7 +149,7 @@ impl PixiEnvironmentSpec {
             self.variants.clone(),
             self.variant_files.clone(),
             self.enabled_protocols.clone(),
-            self.pin_overrides.clone(),
+            self.preferred_build_source.clone(),
         )
         .collect(
             source_specs
diff --git a/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs b/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs
index c6deb8db0a..6e40b768a1 100644
--- a/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs
+++ b/crates/pixi_command_dispatcher/src/solve_pixi/source_metadata_collector.rs
@@ -15,7 +15,6 @@ use thiserror::Error;
 use crate::{
     BuildBackendMetadataSpec, BuildEnvironment, CommandDispatcher, CommandDispatcherError,
     SourceCheckoutError, SourceMetadataSpec,
-    build::SourceCodeLocation,
     executor::ExecutorFutures,
     source_metadata::{CycleEnvironment, SourceMetadata, SourceMetadataError},
 };
@@ -30,7 +29,7 @@ pub struct SourceMetadataCollector {
     enabled_protocols: EnabledProtocols,
     variants: Option<BTreeMap<String, Vec<String>>>,
     variant_files: Option<Vec<PathBuf>>,
-    pin_overrides: BTreeMap<rattler_conda_types::PackageName, PinnedSourceSpec>,
+    preferred_build_sources: BTreeMap<rattler_conda_types::PackageName, PinnedSourceSpec>,
 }
 
 #[derive(Default)]
@@ -79,7 +78,7 @@ impl SourceMetadataCollector {
         variants: Option<BTreeMap<String, Vec<String>>>,
         variant_files: Option<Vec<PathBuf>>,
         enabled_protocols: EnabledProtocols,
-        pin_overrides: BTreeMap<rattler_conda_types::PackageName, PinnedSourceSpec>,
+        preferred_build_sources: BTreeMap<rattler_conda_types::PackageName, PinnedSourceSpec>,
     ) -> Self {
         Self {
             command_queue,
@@ -89,7 +88,7 @@ impl SourceMetadataCollector {
             channel_config,
             variants,
             variant_files,
-            pin_overrides,
+            preferred_build_sources,
         }
     }
 
@@ -138,7 +137,14 @@ impl SourceMetadataCollector {
                                 .map(|source_spec| (name.clone(), source_spec.clone()))
                         }) {
                             // We encountered a transitive source dependency.
-                            specs.push((name, anchor.resolve(source_spec), chain.clone()));
+                            let resolved_location = anchor.resolve(source_spec.location);
+                            specs.push((
+                                name,
+                                SourceSpec {
+                                    location: resolved_location,
+                                },
+                                chain.clone(),
+                            ));
                         } else {
                             // We encountered a transitive dependency that is not a source
                             result.transitive_dependencies.push(spec);
@@ -166,13 +172,13 @@ impl SourceMetadataCollector {
         tracing::trace!("Collecting source metadata for {name:#?}");
 
         // Determine if we should override the build_source pin for this package.
-        let override_pin = self.pin_overrides.get(&name).cloned();
+        let preferred_build_source = self.preferred_build_sources.get(&name).cloned();
 
         // Always checkout the manifest-defined source location (root), discovery
-        // will pick build_source; we only override the build pin later.
-        let source = self
+        // will pick build_source; we only pass preferred locations.
+        let manifest_source_checkout = self
             .command_queue
-            .pin_and_checkout(spec.location, None)
+            .pin_and_checkout(spec.location)
             .await
             .map_err(|err| CollectSourceMetadataError::SourceCheckoutError {
                 name: name.as_source().to_string(),
@@ -186,14 +192,14 @@ impl SourceMetadataCollector {
             .source_metadata(SourceMetadataSpec {
                 package: name.clone(),
                 backend_metadata: BuildBackendMetadataSpec {
-                    source: SourceCodeLocation::new(source.pinned, None),
+                    manifest_source: manifest_source_checkout.pinned,
+                    preferred_build_source,
                     channel_config: self.channel_config.clone(),
                     channels: self.channels.clone(),
                     build_environment: self.build_environment.clone(),
                     variants: self.variants.clone(),
                     variant_files: self.variant_files.clone(),
                     enabled_protocols: self.enabled_protocols.clone(),
-                    pin_override: override_pin,
                 },
             })
             .await
diff --git a/crates/pixi_command_dispatcher/src/source_build/mod.rs b/crates/pixi_command_dispatcher/src/source_build/mod.rs
index ee08dd4cb5..90953bb471 100644
--- a/crates/pixi_command_dispatcher/src/source_build/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build/mod.rs
@@ -220,7 +220,7 @@ impl SourceBuildSpec {
 
         // Check out the source code.
         let manifest_source_checkout = command_dispatcher
-            .checkout_pinned_source(&manifest_source)
+            .checkout_pinned_source(manifest_source.clone())
             .await
             .map_err_with(SourceBuildError::SourceCheckout)?;
 
@@ -258,55 +258,45 @@ impl SourceBuildSpec {
         // 1. Lock file `package_build_source`. Since we're running lock file update before building package it should pin source in there.
         // 2. Manifest package build. This can happen if package isn't added to the dependencies of manifest, so no pinning happens in that case.
         // 3. Manifest source. Just assume that source is located at the same directory as the manifest.
-        let build_source_dir = if let Some(pinned_build_source) = build_source {
-            let build_location =
-                SourceCodeLocation::new(manifest_source.clone(), Some(pinned_build_source.clone()));
-            let build_source_checkout = command_dispatcher
-                .checkout_source_location(&build_location)
+        let build_source_checkout = if let Some(pinned_build_source) = build_source {
+            &command_dispatcher
+                .checkout_pinned_source(pinned_build_source)
                 .await
-                .map_err_with(SourceBuildError::SourceCheckout)?;
-            build_source_checkout.path
+                .map_err_with(SourceBuildError::SourceCheckout)?
         } else if let Some(manifest_build_source) =
             discovered_backend.init_params.build_source.clone()
         {
-            let build_source_checkout = command_dispatcher
-                .pin_and_checkout(
-                    manifest_build_source,
-                    Some(
-                        discovered_backend
-                            .init_params
-                            .manifest_path
-                            .parent()
-                            .ok_or_else(|| {
-                                SourceCheckoutError::ParentDir(
-                                    discovered_backend.init_params.manifest_path.clone(),
-                                )
-                            })
-                            .map_err(SourceBuildError::SourceCheckout)
-                            .map_err(CommandDispatcherError::Failed)?,
-                    ),
-                )
+            let manifest_source_anchor =
+                SourceAnchor::from(SourceSpec::from(manifest_source.clone()));
+            let resolved_build_source = manifest_source_anchor.resolve(manifest_build_source);
+            &command_dispatcher
+                .pin_and_checkout(resolved_build_source)
                 .await
-                .map_err_with(SourceBuildError::SourceCheckout)?;
-            build_source_checkout.path
+                .map_err_with(SourceBuildError::SourceCheckout)?
         } else {
-            manifest_source_checkout.path
+            &manifest_source_checkout
         };
 
         // Instantiate the backend with the discovered information.
-        let backend =
-            command_dispatcher
-                .instantiate_backend(InstantiateBackendSpec {
-                    backend_spec: discovered_backend.backend_spec.clone().resolve(
-                        SourceAnchor::from(SourceSpec::from(manifest_source.clone())),
-                    ),
-                    init_params: discovered_backend.init_params.clone(),
-                    build_source_dir,
-                    channel_config: self.channel_config.clone(),
-                    enabled_protocols: self.enabled_protocols.clone(),
-                })
-                .await
-                .map_err_with(SourceBuildError::Initialize)?;
+        let backend = command_dispatcher
+            .instantiate_backend(InstantiateBackendSpec {
+                backend_spec: discovered_backend
+                    .backend_spec
+                    .clone()
+                    .resolve(SourceAnchor::from(SourceSpec::from(
+                        manifest_source.clone(),
+                    ))),
+                build_source_dir: build_source_checkout.path.clone(),
+                channel_config: self.channel_config.clone(),
+                enabled_protocols: self.enabled_protocols.clone(),
+                workspace_root: discovered_backend.init_params.workspace_root.clone(),
+                manifest_path: discovered_backend.init_params.manifest_path.clone(),
+                project_model: discovered_backend.init_params.project_model.clone(),
+                configuration: discovered_backend.init_params.configuration.clone(),
+                target_configuration: discovered_backend.init_params.target_configuration.clone(),
+            })
+            .await
+            .map_err_with(SourceBuildError::Initialize)?;
 
         // Determine the working directory for the build.
         let work_directory = match std::mem::take(&mut self.work_directory) {
@@ -786,7 +776,7 @@ impl SourceBuildSpec {
                 variants: self.variants.clone(),
                 variant_files: self.variant_files.clone(),
                 enabled_protocols: self.enabled_protocols.clone(),
-                pin_overrides: BTreeMap::new(),
+                preferred_build_source: BTreeMap::new(),
             })
             .await
     }
diff --git a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
index 1b461044dd..8b67630527 100644
--- a/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_build_cache_status/mod.rs
@@ -323,7 +323,7 @@ impl SourceBuildCacheStatusSpec {
 
         // Checkout the source for the package.
         let source_checkout = command_dispatcher
-            .checkout_pinned_source(manifest_source)
+            .checkout_pinned_source(manifest_source.clone())
             .await
             .map_err_with(SourceBuildCacheStatusError::SourceCheckout)?;
 
@@ -369,14 +369,14 @@ impl SourceBuildCacheStatusSpec {
         };
 
         // Checkout the source for the package.
-        let source_checkout = command_dispatcher
-            .checkout_source_location(&self.source)
+        let source_build_checkout = command_dispatcher
+            .checkout_pinned_source(self.source.source_code().clone())
             .await
             .map_err_with(SourceBuildCacheStatusError::SourceCheckout)?;
 
         // Compute the modification time of the files that match the source input globs.
         let glob_time = match GlobModificationTime::from_patterns(
-            &source_checkout.path,
+            &source_build_checkout.path,
             source_info.globs.iter().map(String::as_str),
         ) {
             Ok(glob_time) => glob_time,
diff --git a/crates/pixi_command_dispatcher/src/source_metadata/mod.rs b/crates/pixi_command_dispatcher/src/source_metadata/mod.rs
index 9098600d2f..8600871518 100644
--- a/crates/pixi_command_dispatcher/src/source_metadata/mod.rs
+++ b/crates/pixi_command_dispatcher/src/source_metadata/mod.rs
@@ -59,8 +59,8 @@ impl SourceMetadataSpec {
         skip_all,
         name = "source-metadata",
         fields(
-            manifest_source= %self.backend_metadata.source.manifest_source(),
-            build_source=?self.backend_metadata.source.build_source(),
+            manifest_source= %self.backend_metadata.manifest_source,
+            preferred_build_source=?self.backend_metadata.preferred_build_source,
             name = %self.package.as_source(),
             platform = %self.backend_metadata.build_environment.host_platform,
         )
@@ -370,9 +370,9 @@ impl SourceMetadataSpec {
         if dependencies.dependencies.is_empty() {
             return Ok(vec![]);
         }
-        let pin_overrides = self
+        let preferred_build_source = self
             .backend_metadata
-            .pin_override
+            .preferred_build_source
             .as_ref()
             .map(|pinned| BTreeMap::from([(pkg_name.clone(), pinned.clone())]))
             .unwrap_or_default();
@@ -399,7 +399,7 @@ impl SourceMetadataSpec {
                 variants: self.backend_metadata.variants.clone(),
                 variant_files: self.backend_metadata.variant_files.clone(),
                 enabled_protocols: self.backend_metadata.enabled_protocols.clone(),
-                pin_overrides,
+                preferred_build_source,
             })
             .await
         {
diff --git a/crates/pixi_command_dispatcher/tests/integration/event_tree.rs b/crates/pixi_command_dispatcher/tests/integration/event_tree.rs
index 14a33ecbf3..ce42d3ad55 100644
--- a/crates/pixi_command_dispatcher/tests/integration/event_tree.rs
+++ b/crates/pixi_command_dispatcher/tests/integration/event_tree.rs
@@ -130,7 +130,7 @@ impl EventTree {
                         format!(
                             "{} @ {}",
                             &spec.package.as_source(),
-                            spec.backend_metadata.source
+                            spec.backend_metadata.manifest_source
                         ),
                     );
                     builder.set_event_parent((*id).into(), *context);
@@ -146,7 +146,7 @@ impl EventTree {
                 }
                 Event::SourceMetadataFinished { .. } => {}
                 Event::BuildBackendMetadataQueued { id, context, spec } => {
-                    build_backend_metadata_label.insert(*id, spec.source.to_string());
+                    build_backend_metadata_label.insert(*id, spec.manifest_source.to_string());
                     builder.set_event_parent((*id).into(), *context);
                 }
                 Event::BuildBackendMetadataStarted { id } => {
diff --git a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap
index 02e20f8a35..b5f8bf5d7f 100644
--- a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap
+++ b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__cycle.snap
@@ -16,8 +16,8 @@ ERROR:
 
 TRACE:
 Pixi solve (package_a)
-└── Source metadata (package_a @ (manifest-src: package_a, build-src: undefined))
-    ├── Build backend metadata ((manifest-src: package_a, build-src: undefined))
+└── Source metadata (package_a @ package_a)
+    ├── Build backend metadata (package_a)
     └── Pixi solve (package_b)
-        └── Source metadata (package_b @ (manifest-src: package_b, build-src: undefined))
-            └── Build backend metadata ((manifest-src: package_b, build-src: undefined))
+        └── Source metadata (package_b @ package_b)
+            └── Build backend metadata (package_b)
diff --git a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap
index e5a6313312..05f2dd033f 100644
--- a/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap
+++ b/crates/pixi_command_dispatcher/tests/integration/snapshots/integration__simple_test.snap
@@ -4,13 +4,13 @@ expression: event_tree.to_string()
 ---
 Pixi solve (foobar-desktop)
 ├── Git Checkout (https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
-├── Source metadata (foobar-desktop @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
-│   └── Build backend metadata ((manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
+├── Source metadata (foobar-desktop @ https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
+│   └── Build backend metadata (https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
 │       └── Instantiate tool environment (pixi-build-rattler-build)
 │           ├── Pixi solve (pixi-build-rattler-build)
 │           │   └── Conda solve #0
 │           └── Pixi install (pixi-build-rattler-build)
-├── Source metadata (foobar @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
+├── Source metadata (foobar @ https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a)
 └── Conda solve #1
 Pixi install (test-env)
 ├── Source build (foobar @ (manifest-src: https://github.com/wolfv/pixi-build-examples@8d230eda9b4cdaaefd24aad87fd923d4b7c3c78a, build-src: undefined))
diff --git a/crates/pixi_core/src/lock_file/satisfiability/mod.rs b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
index 88c32d685c..52eaa029d3 100644
--- a/crates/pixi_core/src/lock_file/satisfiability/mod.rs
+++ b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
@@ -1334,7 +1334,10 @@ pub(crate) async fn verify_package_platform_satisfiability(
                             ))
                         })
                     {
-                        let anchored_source = anchor.resolve(source.clone());
+                        let anchored_location = anchor.resolve(source.location.clone());
+                        let anchored_source = SourceSpec {
+                            location: anchored_location,
+                        };
                         conda_queue.push(Dependency::CondaSource(
                             package_name.clone(),
                             spec,
diff --git a/crates/pixi_core/src/lock_file/update.rs b/crates/pixi_core/src/lock_file/update.rs
index 27796fc072..fcb1b5cbd2 100644
--- a/crates/pixi_core/src/lock_file/update.rs
+++ b/crates/pixi_core/src/lock_file/update.rs
@@ -2028,7 +2028,7 @@ async fn spawn_solve_conda_environment_task(
             variants: Some(variants),
             variant_files: Some(variant_files),
             enabled_protocols: Default::default(),
-            pin_overrides,
+            preferred_build_source: pin_overrides,
         })
         .await
         .map_err(|source| SolveCondaEnvironmentError::SolveFailed {
diff --git a/crates/pixi_global/src/common.rs b/crates/pixi_global/src/common.rs
index 73e437af1b..6bbae157bc 100644
--- a/crates/pixi_global/src/common.rs
+++ b/crates/pixi_global/src/common.rs
@@ -1259,7 +1259,7 @@ mod tests {
         #[cfg(windows)]
         {
             for script_name in script_names {
-                let script_path = bin_dir.path().join(format!("{}.bat", script_name));
+                let script_path = bin_dir.path().join(format!("{script_name}.bat"));
                 let script = format!(
                     r#"
             @"{}" %*
@@ -1267,7 +1267,7 @@ mod tests {
                     env_dir
                         .path()
                         .join("bin")
-                        .join(format!("{}.exe", script_name))
+                        .join(format!("{script_name}.exe"))
                         .to_string_lossy()
                 );
                 tokio_fs::write(&script_path, script).await.unwrap();
diff --git a/crates/pixi_global/src/project/mod.rs b/crates/pixi_global/src/project/mod.rs
index 6df70d0cf0..872dc3e6cf 100644
--- a/crates/pixi_global/src/project/mod.rs
+++ b/crates/pixi_global/src/project/mod.rs
@@ -23,7 +23,7 @@ pub use parsed_manifest::{ExposedName, ParsedEnvironment, ParsedManifest};
 use pixi_build_discovery::EnabledProtocols;
 use pixi_command_dispatcher::{
     BuildBackendMetadataSpec, BuildEnvironment, CommandDispatcher, InstallPixiEnvironmentSpec,
-    Limits, PixiEnvironmentSpec, build::SourceCodeLocation,
+    Limits, PixiEnvironmentSpec,
 };
 use pixi_config::{Config, RunPostLinkScripts, default_channel_config, pixi_home};
 use pixi_consts::consts::{self};
@@ -1372,7 +1372,7 @@ impl Project {
     ) -> Result<PackageName, InferPackageNameError> {
         let command_dispatcher = self.command_dispatcher()?;
         let checkout = command_dispatcher
-            .pin_and_checkout(source_spec.location, None)
+            .pin_and_checkout(source_spec.location)
             .await
             .map_err(|e| InferPackageNameError::BuildBackendMetadata(Box::new(e)))?;
 
@@ -1380,7 +1380,8 @@ impl Project {
 
         // Create the metadata spec
         let metadata_spec = BuildBackendMetadataSpec {
-            source: SourceCodeLocation::new(pinned_source_spec, None),
+            manifest_source: pinned_source_spec,
+            preferred_build_source: None,
             channel_config: self.global_channel_config().clone(),
             channels: self
                 .config()
@@ -1392,7 +1393,6 @@ impl Project {
             variants: None,
             variant_files: None,
             enabled_protocols: Default::default(),
-            pin_override: None,
         };
 
         // Get the metadata using the command dispatcher
diff --git a/crates/pixi_record/src/pinned_source.rs b/crates/pixi_record/src/pinned_source.rs
index 0052cf01c6..05c06b81bf 100644
--- a/crates/pixi_record/src/pinned_source.rs
+++ b/crates/pixi_record/src/pinned_source.rs
@@ -129,6 +129,89 @@ impl PinnedSourceSpec {
             PinnedSourceSpec::Path(spec) => spec.identifiable_url(),
         }
     }
+
+    /// Checks if this pinned source spec matches a given source spec.
+    ///
+    /// This method determines if the pinned source and the source spec refer to
+    /// the same underlying source, ignoring version-specific details like git
+    /// commits or archive hashes. This is useful for determining if a pinned
+    /// source satisfies a given source requirement.
+    ///
+    /// # Matching Rules
+    ///
+    /// - **Path sources**: Paths must be exactly equal (same normalized path)
+    /// - **Git sources**: Repository URLs must match (ignoring credentials and
+    ///   case), and subdirectories must match if specified in the source spec
+    /// - **URL sources**: URLs must be exactly equal (including all components)
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use pixi_record::{PinnedSourceSpec, PinnedGitSpec, PinnedGitCheckout};
+    /// use pixi_spec::{SourceSpec, SourceLocationSpec, GitSpec, GitReference};
+    /// use pixi_git::sha::GitSha;
+    /// use url::Url;
+    /// use std::str::FromStr;
+    ///
+    /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+    /// // Git source matching
+    /// let pinned_git = PinnedSourceSpec::Git(PinnedGitSpec {
+    ///     git: Url::parse("https://github.com/user/repo")?,
+    ///     source: PinnedGitCheckout {
+    ///         commit: GitSha::from_str("abc123def456")?,
+    ///         subdirectory: None,
+    ///         reference: GitReference::DefaultBranch,
+    ///     },
+    /// });
+    ///
+    /// let source_spec = SourceSpec {
+    ///     location: SourceLocationSpec::Git(GitSpec {
+    ///         git: Url::parse("https://github.com/user/repo.git")?,
+    ///         rev: None,
+    ///         subdirectory: None,
+    ///     }),
+    /// };
+    ///
+    /// assert!(pinned_git.matches_source_spec(&source_spec));
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn matches_source_spec(&self, source_spec: &SourceSpec) -> bool {
+        match (self, &source_spec.location) {
+            // Path sources: paths must be exactly equal
+            (PinnedSourceSpec::Path(pinned_path), SourceLocationSpec::Path(source_path)) => {
+                pinned_path.path == source_path.path
+            }
+
+            // Git sources: repository URLs must match, subdirectories must match if specified
+            (PinnedSourceSpec::Git(pinned_git), SourceLocationSpec::Git(source_git)) => {
+                use pixi_git::url::RepositoryUrl;
+
+                // Compare repository URLs (ignoring commit/branch details)
+                let pinned_repo = RepositoryUrl::new(&pinned_git.git);
+                let source_repo = RepositoryUrl::new(&source_git.git);
+
+                if pinned_repo != source_repo {
+                    return false;
+                }
+
+                // If source spec specifies a subdirectory, it must match
+                match (&source_git.subdirectory, &pinned_git.source.subdirectory) {
+                    (Some(source_subdir), Some(pinned_subdir)) => source_subdir == pinned_subdir,
+                    (Some(_), None) => false, // Source expects subdirectory, but pinned doesn't have one
+                    (None, _) => true,        // Source doesn't care about subdirectory
+                }
+            }
+
+            // URL sources: URLs must be exactly equal
+            (PinnedSourceSpec::Url(pinned_url), SourceLocationSpec::Url(source_url)) => {
+                pinned_url.url == source_url.url
+            }
+
+            // Mismatched types never match
+            _ => false,
+        }
+    }
 }
 
 impl MutablePinnedSourceSpec {
@@ -277,6 +360,7 @@ pub struct PinnedGitSpec {
     /// The URL of the repository without the revision and subdirectory
     /// fragment.
     pub git: Url,
+
     /// The resolved git checkout.
     #[serde(flatten)]
     pub source: PinnedGitCheckout,
@@ -1006,4 +1090,349 @@ mod tests {
             SourceMismatchError::GitSubdirectoryMismatch { .. }
         ));
     }
+
+    mod matches_source_spec {
+        use super::*;
+        use pixi_spec::{PathSourceSpec, SourceLocationSpec, SourceSpec, UrlSourceSpec};
+        use typed_path::Utf8TypedPathBuf;
+
+        use crate::{PinnedPathSpec, PinnedSourceSpec, PinnedUrlSpec};
+
+        #[test]
+        fn test_path_exact_match() {
+            let pinned = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: Utf8TypedPathBuf::from("/path/to/source"),
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Path(PathSourceSpec {
+                    path: Utf8TypedPathBuf::from("/path/to/source"),
+                }),
+            };
+
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_path_mismatch() {
+            let pinned = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: Utf8TypedPathBuf::from("/path/to/source"),
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Path(PathSourceSpec {
+                    path: Utf8TypedPathBuf::from("/different/path"),
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_same_repo_without_git_suffix() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo.git").unwrap(),
+                    rev: None,
+                    subdirectory: None,
+                }),
+            };
+
+            // Should match despite .git suffix difference
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_same_repo_with_git_suffix() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo.git").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: None,
+                }),
+            };
+
+            // Should match despite .git suffix difference
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_different_repos() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo1").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo2").unwrap(),
+                    rev: None,
+                    subdirectory: None,
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_same_repo_no_subdirectory_in_spec() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: Some("subdir".to_string()),
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: None,
+                }),
+            };
+
+            // Should match - spec doesn't care about subdirectory
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_same_repo_matching_subdirectory() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: Some("subdir".to_string()),
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: Some("subdir".to_string()),
+                }),
+            };
+
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_same_repo_mismatching_subdirectory() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: Some("subdir1".to_string()),
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: Some("subdir2".to_string()),
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_spec_requires_subdirectory_but_pinned_has_none() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: Some("subdir".to_string()),
+                }),
+            };
+
+            // Should not match - spec requires a subdirectory that pinned doesn't have
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_url_exact_match() {
+            let pinned = PinnedSourceSpec::Url(PinnedUrlSpec {
+                url: Url::parse("https://example.com/archive.tar.gz").unwrap(),
+                sha256: rattler_digest::parse_digest_from_hex::<rattler_digest::Sha256>(
+                    "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                )
+                .unwrap(),
+                md5: None,
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Url(UrlSourceSpec {
+                    url: Url::parse("https://example.com/archive.tar.gz").unwrap(),
+                    sha256: None,
+                    md5: None,
+                }),
+            };
+
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_url_mismatch() {
+            let pinned = PinnedSourceSpec::Url(PinnedUrlSpec {
+                url: Url::parse("https://example.com/archive.tar.gz").unwrap(),
+                sha256: rattler_digest::parse_digest_from_hex::<rattler_digest::Sha256>(
+                    "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                )
+                .unwrap(),
+                md5: None,
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Url(UrlSourceSpec {
+                    url: Url::parse("https://example.com/different.tar.gz").unwrap(),
+                    sha256: None,
+                    md5: None,
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_type_mismatch_path_vs_git() {
+            let pinned = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: Utf8TypedPathBuf::from("/path/to/source"),
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: None,
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_type_mismatch_git_vs_url() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Url(UrlSourceSpec {
+                    url: Url::parse("https://example.com/archive.tar.gz").unwrap(),
+                    sha256: None,
+                    md5: None,
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_type_mismatch_url_vs_path() {
+            let pinned = PinnedSourceSpec::Url(PinnedUrlSpec {
+                url: Url::parse("https://example.com/archive.tar.gz").unwrap(),
+                sha256: rattler_digest::parse_digest_from_hex::<rattler_digest::Sha256>(
+                    "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                )
+                .unwrap(),
+                md5: None,
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Path(PathSourceSpec {
+                    path: Utf8TypedPathBuf::from("/path/to/source"),
+                }),
+            };
+
+            assert!(!pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_ignores_different_commits() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/user/repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::Rev("v1.0.0".to_string()),
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: Some(GitReference::Rev("v2.0.0".to_string())),
+                    subdirectory: None,
+                }),
+            };
+
+            // Should match - we only compare repository and subdirectory, not the commit/rev
+            assert!(pinned.matches_source_spec(&spec));
+        }
+
+        #[test]
+        fn test_git_case_insensitive_github() {
+            let pinned = PinnedSourceSpec::Git(PinnedGitSpec {
+                git: Url::parse("https://github.com/User/Repo").unwrap(),
+                source: PinnedGitCheckout {
+                    commit: GitSha::from_str("abc123def456789012345678901234567890abcd").unwrap(),
+                    subdirectory: None,
+                    reference: GitReference::DefaultBranch,
+                },
+            });
+
+            let spec = SourceSpec {
+                location: SourceLocationSpec::Git(GitSpec {
+                    git: Url::parse("https://github.com/user/repo").unwrap(),
+                    rev: None,
+                    subdirectory: None,
+                }),
+            };
+
+            // Should match - GitHub URLs are case-insensitive
+            assert!(pinned.matches_source_spec(&spec));
+        }
+    }
 }
diff --git a/crates/pixi_spec/src/source_anchor.rs b/crates/pixi_spec/src/source_anchor.rs
index e9a0f12c60..35f05867f3 100644
--- a/crates/pixi_spec/src/source_anchor.rs
+++ b/crates/pixi_spec/src/source_anchor.rs
@@ -13,62 +13,55 @@ pub enum SourceAnchor {
     Workspace,
 
     /// The source is relative to another source package.
-    Source(SourceSpec),
+    Source(SourceLocationSpec),
 }
 
 impl From<SourceSpec> for SourceAnchor {
     fn from(value: SourceSpec) -> Self {
+        SourceAnchor::Source(value.location)
+    }
+}
+
+impl From<SourceLocationSpec> for SourceAnchor {
+    fn from(value: SourceLocationSpec) -> Self {
         SourceAnchor::Source(value)
     }
 }
 
 impl SourceAnchor {
-    /// Resolve a source spec relative to this anchor.
-    pub fn resolve(&self, spec: SourceSpec) -> SourceSpec {
+    /// Resolve a source location spec relative to this anchor.
+    pub fn resolve(&self, spec: SourceLocationSpec) -> SourceLocationSpec {
         // If this instance is already anchored to the workspace we can simply return
         // immediately.
         let SourceAnchor::Source(base) = self else {
-            return match spec.location {
-                SourceLocationSpec::Url(url) => SourceSpec {
-                    location: SourceLocationSpec::Url(url),
-                },
-                SourceLocationSpec::Git(git) => SourceSpec {
-                    location: SourceLocationSpec::Git(git),
-                },
+            return match spec {
+                SourceLocationSpec::Url(url) => SourceLocationSpec::Url(url),
+                SourceLocationSpec::Git(git) => SourceLocationSpec::Git(git),
                 SourceLocationSpec::Path(PathSourceSpec { path }) => {
-                    SourceSpec {
-                        location: SourceLocationSpec::Path(PathSourceSpec {
-                            // Normalize the input path.
-                            path: normalize_typed(path.to_path()),
-                        }),
-                    }
+                    SourceLocationSpec::Path(PathSourceSpec {
+                        // Normalize the input path.
+                        path: normalize_typed(path.to_path()),
+                    })
                 }
             };
         };
 
         // Only path specs can be relative.
-        let SourceSpec {
-            location: SourceLocationSpec::Path(PathSourceSpec { path }),
-        } = spec
-        else {
+        let SourceLocationSpec::Path(PathSourceSpec { path }) = spec else {
             return spec;
         };
 
         // If the path is absolute we can just return it.
         if path.is_absolute() || path.starts_with("~") {
-            return SourceSpec {
-                location: SourceLocationSpec::Path(PathSourceSpec { path }),
-            };
+            return SourceLocationSpec::Path(PathSourceSpec { path });
         }
 
-        match &base.location {
+        match base {
             SourceLocationSpec::Path(PathSourceSpec { path: base }) => {
                 let relative_path = normalize_typed(base.join(path).to_path());
-                SourceSpec {
-                    location: SourceLocationSpec::Path(PathSourceSpec {
-                        path: relative_path,
-                    }),
-                }
+                SourceLocationSpec::Path(PathSourceSpec {
+                    path: relative_path,
+                })
             }
             SourceLocationSpec::Url(UrlSourceSpec { .. }) => {
                 unimplemented!("Cannot resolve relative paths for URL sources")
@@ -83,13 +76,11 @@ impl SourceAnchor {
                         .join(path)
                         .to_path(),
                 );
-                SourceSpec {
-                    location: SourceLocationSpec::Git(GitSpec {
-                        git: git.clone(),
-                        rev: rev.clone(),
-                        subdirectory: Some(relative_subdir.to_string()),
-                    }),
-                }
+                SourceLocationSpec::Git(GitSpec {
+                    git: git.clone(),
+                    rev: rev.clone(),
+                    subdirectory: Some(relative_subdir.to_string()),
+                })
             }
         }
     }

From 1975d42db492e5ea63cf9c98992eed0a9ba2a9da Mon Sep 17 00:00:00 2001
From: Bas Zalmstra <4995967+baszalmstra@users.noreply.github.com>
Date: Wed, 5 Nov 2025 13:38:52 +0100
Subject: [PATCH 08/21] wip: include the workspace root when serializing and
 deserializing the lock file

---
 Cargo.lock                                    |   1 +
 .../src/lock_file/satisfiability/mod.rs       |   4 +-
 crates/pixi_core/src/lock_file/update.rs      |  17 +-
 crates/pixi_record/Cargo.toml                 |   1 +
 crates/pixi_record/src/lib.rs                 |  66 +--
 crates/pixi_record/src/pinned_source.rs       | 190 +++++++++
 crates/pixi_record/src/source_record.rs       | 393 +++++++++++++++---
 7 files changed, 585 insertions(+), 87 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 123a855199..6f839e8d02 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5297,6 +5297,7 @@ version = "0.1.0"
 dependencies = [
  "file_url",
  "miette 7.6.0",
+ "pathdiff",
  "pixi_git",
  "pixi_spec",
  "rattler_conda_types",
diff --git a/crates/pixi_core/src/lock_file/satisfiability/mod.rs b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
index 52eaa029d3..d5477e716f 100644
--- a/crates/pixi_core/src/lock_file/satisfiability/mod.rs
+++ b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
@@ -685,9 +685,7 @@ pub async fn verify_platform_satisfiability(
             LockedPackageRef::Conda(conda) => {
                 let url = conda.location().clone();
                 pixi_records.push(
-                    conda
-                        .clone()
-                        .try_into()
+                    PixiRecord::from_conda_package_data(conda.clone(), project_root)
                         .map_err(|e| PlatformUnsat::CorruptedEntry(url.to_string(), e))?,
                 );
             }
diff --git a/crates/pixi_core/src/lock_file/update.rs b/crates/pixi_core/src/lock_file/update.rs
index fcb1b5cbd2..9d0bd41f55 100644
--- a/crates/pixi_core/src/lock_file/update.rs
+++ b/crates/pixi_core/src/lock_file/update.rs
@@ -502,7 +502,8 @@ impl<'p> LockFileDerivedData<'p> {
                         LockedPackageRef::Pypi(data, _) => Either::Right(data.name.clone()),
                     });
 
-                let pixi_records = locked_packages_to_pixi_records(conda_packages)?;
+                let pixi_records =
+                    locked_packages_to_pixi_records(conda_packages, self.workspace.root())?;
 
                 let pypi_records = pypi_packages
                     .into_iter()
@@ -679,7 +680,7 @@ impl<'p> LockFileDerivedData<'p> {
                 } else {
                     Vec::new()
                 };
-                let records = locked_packages_to_pixi_records(packages)?;
+                let records = locked_packages_to_pixi_records(packages, self.workspace.root())?;
 
                 // Update the conda prefix
                 let CondaPrefixUpdated {
@@ -767,12 +768,13 @@ impl PackageFilterNames {
 
 fn locked_packages_to_pixi_records(
     conda_packages: Vec<LockedPackageRef<'_>>,
+    workspace_root: &std::path::Path,
 ) -> Result<Vec<PixiRecord>, Report> {
     let pixi_records = conda_packages
         .into_iter()
         .filter_map(LockedPackageRef::as_conda)
         .cloned()
-        .map(PixiRecord::try_from)
+        .map(|data| PixiRecord::from_conda_package_data(data, workspace_root))
         .collect::<Result<Vec<_>, _>>()
         .into_diagnostic()?;
     Ok(pixi_records)
@@ -1130,6 +1132,7 @@ impl<'p> UpdateContextBuilder<'p> {
 
         // Extract the current conda records from the lock-file
         // TODO: Should we parallelize this? Measure please.
+        let workspace_root = project.root();
         let locked_repodata_records = project
             .environments()
             .into_iter()
@@ -1143,7 +1146,7 @@ impl<'p> UpdateContextBuilder<'p> {
                             .map(|(platform, records)| {
                                 records
                                     .cloned()
-                                    .map(PixiRecord::try_from)
+                                    .map(|data| PixiRecord::from_conda_package_data(data, workspace_root))
                                     .collect::<Result<Vec<_>, _>>()
                                     .map(|records| {
                                         (platform, Arc::new(PixiRecordsByName::from_iter(records)))
@@ -1826,7 +1829,11 @@ impl<'p> UpdateContext<'p> {
             for platform in environment.platforms() {
                 if let Some(records) = self.take_latest_repodata_records(&environment, platform) {
                     for record in records.into_inner() {
-                        builder.add_conda_package(&environment_name, platform, record.into());
+                        builder.add_conda_package(
+                            &environment_name,
+                            platform,
+                            record.into_conda_package_data(project.root()),
+                        );
                     }
                 }
                 if let Some(records) = self.take_latest_pypi_records(&environment, platform) {
diff --git a/crates/pixi_record/Cargo.toml b/crates/pixi_record/Cargo.toml
index 31a4990a4a..92e3657806 100644
--- a/crates/pixi_record/Cargo.toml
+++ b/crates/pixi_record/Cargo.toml
@@ -12,6 +12,7 @@ version = "0.1.0"
 [dependencies]
 file_url = { workspace = true }
 miette = { workspace = true }
+pathdiff = { workspace = true }
 pixi_git = { workspace = true }
 pixi_spec = { workspace = true, features = ["rattler_lock"] }
 rattler_conda_types = { workspace = true }
diff --git a/crates/pixi_record/src/lib.rs b/crates/pixi_record/src/lib.rs
index 7992cc29ea..d9e0928b1b 100644
--- a/crates/pixi_record/src/lib.rs
+++ b/crates/pixi_record/src/lib.rs
@@ -38,6 +38,43 @@ impl PixiRecord {
         }
     }
 
+    /// Convert to CondaPackageData with paths made relative to workspace_root.
+    /// This should be used when writing to the lock file.
+    pub fn into_conda_package_data(
+        self,
+        workspace_root: &std::path::Path,
+    ) -> CondaPackageData {
+        match self {
+            PixiRecord::Binary(record) => record.into(),
+            PixiRecord::Source(record) => {
+                CondaPackageData::Source(record.into_conda_source_data(workspace_root))
+            }
+        }
+    }
+
+    /// Create PixiRecord from CondaPackageData with paths resolved relative to workspace_root.
+    /// This should be used when reading from the lock file.
+    pub fn from_conda_package_data(
+        data: CondaPackageData,
+        workspace_root: &std::path::Path,
+    ) -> Result<Self, ParseLockFileError> {
+        let record = match data {
+            CondaPackageData::Binary(value) => {
+                let location = value.location.clone();
+                PixiRecord::Binary(value.try_into().map_err(|err| match err {
+                    ConversionError::Missing(field) => ParseLockFileError::Missing(location, field),
+                    ConversionError::LocationToUrlConversionError(err) => {
+                        ParseLockFileError::InvalidRecordUrl(location, err)
+                    }
+                })?)
+            }
+            CondaPackageData::Source(value) => {
+                PixiRecord::Source(SourceRecord::from_conda_source_data(value, workspace_root)?)
+            }
+        };
+        Ok(record)
+    }
+
     /// Returns a reference to the binary record if it is a binary record.
     pub fn as_binary(&self) -> Option<&RepoDataRecord> {
         match self {
@@ -104,35 +141,6 @@ pub enum ParseLockFileError {
     PinnedSourceSpecError(#[from] pinned_source::ParseError),
 }
 
-impl TryFrom<CondaPackageData> for PixiRecord {
-    type Error = ParseLockFileError;
-
-    fn try_from(value: CondaPackageData) -> Result<Self, Self::Error> {
-        let record = match value {
-            CondaPackageData::Binary(value) => {
-                let location = value.location.clone();
-                PixiRecord::Binary(value.try_into().map_err(|err| match err {
-                    ConversionError::Missing(field) => ParseLockFileError::Missing(location, field),
-                    ConversionError::LocationToUrlConversionError(err) => {
-                        ParseLockFileError::InvalidRecordUrl(location, err)
-                    }
-                })?)
-            }
-            CondaPackageData::Source(value) => PixiRecord::Source(value.try_into()?),
-        };
-        Ok(record)
-    }
-}
-
-impl From<PixiRecord> for CondaPackageData {
-    fn from(value: PixiRecord) -> Self {
-        match value {
-            PixiRecord::Binary(record) => record.into(),
-            PixiRecord::Source(record) => record.into(),
-        }
-    }
-}
-
 impl Matches<PixiRecord> for NamelessMatchSpec {
     fn matches(&self, record: &PixiRecord) -> bool {
         match record {
diff --git a/crates/pixi_record/src/pinned_source.rs b/crates/pixi_record/src/pinned_source.rs
index 05c06b81bf..759e5c49b3 100644
--- a/crates/pixi_record/src/pinned_source.rs
+++ b/crates/pixi_record/src/pinned_source.rs
@@ -212,6 +212,97 @@ impl PinnedSourceSpec {
             _ => false,
         }
     }
+
+    /// Makes this pinned source relative to another pinned source if both are path sources
+    /// or both are git sources pointing to the same repository.
+    /// This is useful for making `build_source` relative to `manifest_source` in lock files.
+    ///
+    /// Returns `None` if:
+    /// - Not a compatible combination (different types or different git repos)
+    /// - The sources cannot be made relative to each other
+    ///
+    /// # Arguments
+    /// * `base` - The base pinned source to make this path relative to (typically the manifest_source)
+    pub fn make_relative_to(&self, base: &PinnedSourceSpec) -> Option<Self> {
+        use pixi_git::url::RepositoryUrl;
+        use typed_path::{Utf8Component, Utf8UnixPath};
+
+        match (self, base) {
+            // Path-to-Path: Make the path relative
+            (PinnedSourceSpec::Path(this_path), PinnedSourceSpec::Path(base_path)) => {
+                // Base path is a directory (not a file path)
+                // Create a temporary Path for the base directory
+                let base_dir = Path::new(base_path.path.as_str());
+
+                Some(PinnedSourceSpec::Path(this_path.make_relative_to(base_dir)))
+            }
+            // Git-to-Git: If same repository, convert to a relative path based on subdirectories
+            (PinnedSourceSpec::Git(this_git), PinnedSourceSpec::Git(base_git)) => {
+                // Check if both point to the same repository
+                let this_repo = RepositoryUrl::new(&this_git.git);
+                let base_repo = RepositoryUrl::new(&base_git.git);
+
+                if this_repo != base_repo {
+                    // Different repositories, can't make relative
+                    return None;
+                }
+
+                // Same repository - compute relative path between subdirectories
+                let base_subdir = base_git.source.subdirectory.as_deref().unwrap_or("");
+                let this_subdir = this_git.source.subdirectory.as_deref().unwrap_or("");
+
+                // If both point to the same subdirectory, don't relativize (keep as Git)
+                if base_subdir == this_subdir {
+                    return None;
+                }
+
+                // Always use Unix-style paths for Git subdirectories
+                let base_unix = Utf8UnixPath::new(base_subdir);
+                let this_unix = Utf8UnixPath::new(this_subdir);
+
+                // Try to compute relative path
+                if let Ok(rel) = this_unix.strip_prefix(base_unix) {
+                    // this_subdir is under base_subdir
+                    Some(PinnedSourceSpec::Path(PinnedPathSpec {
+                        path: rel.as_str().into(),
+                    }))
+                } else {
+                    // Need to compute relative path using .. components
+                    let base_components: Vec<_> = base_unix.components().collect();
+                    let this_components: Vec<_> = this_unix.components().collect();
+
+                    // Find common prefix
+                    let common = base_components
+                        .iter()
+                        .zip(this_components.iter())
+                        .take_while(|(a, b)| a == b)
+                        .count();
+
+                    // Build relative path: go up from base, then down to target
+                    let ups = base_components.len() - common;
+                    let mut rel_path = String::new();
+                    for _ in 0..ups {
+                        if !rel_path.is_empty() {
+                            rel_path.push('/');
+                        }
+                        rel_path.push_str("..");
+                    }
+                    for comp in &this_components[common..] {
+                        if !rel_path.is_empty() {
+                            rel_path.push('/');
+                        }
+                        rel_path.push_str(comp.as_str());
+                    }
+
+                    Some(PinnedSourceSpec::Path(PinnedPathSpec {
+                        path: rel_path.into(),
+                    }))
+                }
+            }
+            // Different types or incompatible sources
+            _ => None,
+        }
+    }
 }
 
 impl MutablePinnedSourceSpec {
@@ -464,6 +555,105 @@ impl PinnedPathSpec {
         }
     }
 
+    /// Makes this path relative to another path if possible.
+    /// If the path is already relative or cannot be made relative, returns self unchanged.
+    ///
+    /// # Arguments
+    /// * `base` - The base path to make this path relative to
+    pub fn make_relative_to(&self, base: &Path) -> Self {
+        use typed_path::{Utf8Component, Utf8UnixPath, Utf8WindowsPath};
+
+        // Check if the path is already relative
+        let is_relative = if self.path.as_str().starts_with('/') {
+            // Unix absolute path
+            false
+        } else if self.path.as_str().len() >= 2 && self.path.as_str().chars().nth(1) == Some(':') {
+            // Windows absolute path (C:\...)
+            false
+        } else {
+            // Relative path
+            true
+        };
+
+        if is_relative {
+            return self.clone();
+        }
+
+        // Convert base to string for comparison
+        let base_str = base.to_string_lossy();
+
+        // Determine if we're working with Unix or Windows paths
+        let is_unix_style = self.path.as_str().starts_with('/');
+
+        if is_unix_style {
+            // Use Unix path logic
+            let this_unix = Utf8UnixPath::new(self.path.as_str());
+            let base_unix = Utf8UnixPath::new(&base_str);
+
+            if let Ok(rel) = this_unix.strip_prefix(base_unix) {
+                Self {
+                    path: rel.as_str().into(),
+                }
+            } else {
+                // Try using pathdiff for more complex relativization
+                let this_components: Vec<_> = this_unix.components().collect();
+                let base_components: Vec<_> = base_unix.components().collect();
+
+                // Find common prefix
+                let common = this_components
+                    .iter()
+                    .zip(base_components.iter())
+                    .take_while(|(a, b)| a == b)
+                    .count();
+
+                if common == 0 {
+                    // No common prefix, keep absolute
+                    return self.clone();
+                }
+
+                // Build relative path: go up from base, then down to target
+                let ups = base_components.len() - common;
+                let mut rel_path = String::new();
+                for _ in 0..ups {
+                    if !rel_path.is_empty() {
+                        rel_path.push('/');
+                    }
+                    rel_path.push_str("..");
+                }
+                for comp in &this_components[common..] {
+                    if !rel_path.is_empty() {
+                        rel_path.push('/');
+                    }
+                    rel_path.push_str(comp.as_str());
+                }
+
+                Self {
+                    path: rel_path.into(),
+                }
+            }
+        } else {
+            // Use Windows path logic
+            let this_windows = Utf8WindowsPath::new(self.path.as_str());
+            let base_windows = Utf8WindowsPath::new(&base_str);
+
+            if let Ok(rel) = this_windows.strip_prefix(base_windows) {
+                Self {
+                    path: rel.as_str().into(),
+                }
+            } else {
+                // For Windows, fall back to pathdiff with native paths
+                let native_path = Path::new(self.path.as_str());
+                if let Some(relative_path) = pathdiff::diff_paths(native_path, base) {
+                    Self {
+                        path: relative_path.to_string_lossy().to_string().into(),
+                    }
+                } else {
+                    self.clone()
+                }
+            }
+        }
+    }
+
     /// Returns a URL that uniquely identifies this path spec. This URL is not
     /// portable, e.g. it might result in a different URL on different systems.
     pub fn identifiable_url(&self) -> Url {
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index 68bf60c0b5..99502aa7d3 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -7,7 +7,7 @@ use pixi_git::sha::GitSha;
 use pixi_spec::{GitReference, SourceSpec};
 use rattler_conda_types::{MatchSpec, Matches, NamelessMatchSpec, PackageRecord};
 use rattler_digest::{Sha256, Sha256Hash};
-use rattler_lock::{CondaPackageData, CondaSourceData, GitShallowSpec, PackageBuildSource};
+use rattler_lock::{CondaSourceData, GitShallowSpec, PackageBuildSource};
 use serde::{Deserialize, Serialize};
 use typed_path::Utf8TypedPathBuf;
 
@@ -55,62 +55,86 @@ pub struct InputHash {
     pub globs: BTreeSet<String>,
 }
 
-impl From<SourceRecord> for CondaPackageData {
-    fn from(value: SourceRecord) -> Self {
-        let package_build_source = value.build_source.map(|s| match s {
-            PinnedSourceSpec::Url(pinned_url_spec) => PackageBuildSource::Url {
-                url: pinned_url_spec.url,
-                sha256: pinned_url_spec.sha256,
-                subdir: None,
-            },
-            PinnedSourceSpec::Git(pinned_git_spec) => {
-                let subdirectory = pinned_git_spec
-                    .source
-                    .subdirectory
-                    .as_deref()
-                    .map(Utf8TypedPathBuf::from);
-
-                let spec = match &pinned_git_spec.source.reference {
-                    GitReference::Branch(branch) => Some(GitShallowSpec::Branch(branch.clone())),
-                    GitReference::Tag(tag) => Some(GitShallowSpec::Tag(tag.clone())),
-                    GitReference::Rev(_) => Some(GitShallowSpec::Rev),
-                    GitReference::DefaultBranch => None,
-                };
+impl SourceRecord {
+    /// Convert to CondaSourceData with paths made relative to workspace_root.
+    /// This should be used when writing to the lock file.
+    ///
+    /// TODO: Currently this doesn't use workspace_root and just makes build_source
+    /// relative to manifest_source. Future implementation should make both relative
+    /// to workspace_root first.
+    pub fn into_conda_source_data(
+        self,
+        _workspace_root: &std::path::Path,
+    ) -> CondaSourceData {
+        let package_build_source = self.build_source.map(|s| {
+            // Try to make build_source relative to manifest_source
+            let s = s.make_relative_to(&self.manifest_source).unwrap_or(s);
 
-                PackageBuildSource::Git {
-                    url: pinned_git_spec.git,
-                    spec,
-                    rev: pinned_git_spec.source.commit.to_string(),
-                    subdir: subdirectory,
+            match s {
+                PinnedSourceSpec::Url(pinned_url_spec) => PackageBuildSource::Url {
+                    url: pinned_url_spec.url,
+                    sha256: pinned_url_spec.sha256,
+                    subdir: None,
+                },
+                PinnedSourceSpec::Git(pinned_git_spec) => {
+                    let subdirectory = pinned_git_spec
+                        .source
+                        .subdirectory
+                        .as_deref()
+                        .map(Utf8TypedPathBuf::from);
+
+                    let spec = match &pinned_git_spec.source.reference {
+                        GitReference::Branch(branch) => {
+                            Some(GitShallowSpec::Branch(branch.clone()))
+                        }
+                        GitReference::Tag(tag) => Some(GitShallowSpec::Tag(tag.clone())),
+                        GitReference::Rev(_) => Some(GitShallowSpec::Rev),
+                        GitReference::DefaultBranch => None,
+                    };
+
+                    PackageBuildSource::Git {
+                        url: pinned_git_spec.git,
+                        spec,
+                        rev: pinned_git_spec.source.commit.to_string(),
+                        subdir: subdirectory,
+                    }
                 }
+                PinnedSourceSpec::Path(pinned_path) => PackageBuildSource::Path {
+                    path: pinned_path.path,
+                },
             }
-            PinnedSourceSpec::Path(pinned_path) => PackageBuildSource::Path {
-                path: pinned_path.path,
-            },
         });
-        CondaPackageData::Source(CondaSourceData {
-            package_record: value.package_record,
-            location: value.manifest_source.clone().into(),
+
+        CondaSourceData {
+            package_record: self.package_record,
+            location: self.manifest_source.clone().into(),
             package_build_source,
-            input: value.input_hash.map(|i| rattler_lock::InputHash {
+            input: self.input_hash.map(|i| rattler_lock::InputHash {
                 hash: i.hash,
-                // TODO: fix this in rattler
                 globs: Vec::from_iter(i.globs),
             }),
-            sources: value
+            sources: self
                 .sources
                 .into_iter()
                 .map(|(k, v)| (k, v.into()))
                 .collect(),
-        })
+        }
     }
-}
 
-impl TryFrom<CondaSourceData> for SourceRecord {
-    type Error = ParseLockFileError;
+    /// Create SourceRecord from CondaSourceData with paths resolved relative to workspace_root.
+    /// This should be used when reading from the lock file.
+    ///
+    /// TODO: Currently this doesn't use workspace_root and just resolves build_source
+    /// relative to manifest_source. Future implementation should resolve both against
+    /// workspace_root first.
+    pub fn from_conda_source_data(
+        data: CondaSourceData,
+        _workspace_root: &std::path::Path,
+    ) -> Result<Self, ParseLockFileError> {
 
-    fn try_from(value: CondaSourceData) -> Result<Self, Self::Error> {
-        let pinned_source_spec = value.package_build_source.map(|source| match source {
+        let manifest_source: PinnedSourceSpec = data.location.try_into()?;
+
+        let pinned_source_spec = data.package_build_source.map(|source| match source {
             PackageBuildSource::Git {
                 url,
                 spec,
@@ -143,18 +167,21 @@ impl TryFrom<CondaSourceData> for SourceRecord {
                 md5: None,
             }),
             PackageBuildSource::Path { path } => {
+                // Keep paths as-is from the lock file
+                // They will be resolved later by the code that uses them
                 PinnedSourceSpec::Path(crate::PinnedPathSpec { path })
             }
         });
+
         Ok(Self {
-            package_record: value.package_record,
-            manifest_source: value.location.try_into()?,
-            input_hash: value.input.map(|hash| InputHash {
+            package_record: data.package_record,
+            manifest_source,
+            input_hash: data.input.map(|hash| InputHash {
                 hash: hash.hash,
                 globs: BTreeSet::from_iter(hash.globs),
             }),
             build_source: pinned_source_spec,
-            sources: value
+            sources: data
                 .sources
                 .into_iter()
                 .map(|(k, v)| (k, SourceSpec::from(v)))
@@ -238,9 +265,9 @@ mod tests {
             sources: Default::default(),
         };
 
-        let CondaPackageData::Source(conda_source) = record.clone().into() else {
-            panic!("expected source package data");
-        };
+        let conda_source = record
+            .clone()
+            .into_conda_source_data(&std::path::PathBuf::from("/workspace"));
 
         let package_build_source = conda_source
             .package_build_source
@@ -263,7 +290,11 @@ mod tests {
         assert!(matches!(spec, Some(GitShallowSpec::Branch(branch)) if branch == "main"));
         assert_eq!(rev, "0123456789abcdef0123456789abcdef01234567");
 
-        let roundtrip = SourceRecord::try_from(conda_source).expect("roundtrip should succeed");
+        let roundtrip = SourceRecord::from_conda_source_data(
+            conda_source,
+            &std::path::PathBuf::from("/workspace"),
+        )
+        .expect("roundtrip should succeed");
         let Some(PinnedSourceSpec::Git(roundtrip_git)) = roundtrip.build_source else {
             panic!("expected git pinned source");
         };
@@ -273,4 +304,266 @@ mod tests {
         );
         assert_eq!(roundtrip_git.git, git_url);
     }
+
+    #[test]
+    fn package_build_source_path_is_made_relative() {
+        use typed_path::Utf8TypedPathBuf;
+
+        let package_record: PackageRecord = serde_json::from_value(json!({
+            "name": "example",
+            "version": "1.0.0",
+            "build": "0",
+            "build_number": 0,
+            "subdir": "noarch",
+        }))
+        .expect("valid package record");
+
+        // Manifest is in /workspace/recipes directory
+        let manifest_source = PinnedSourceSpec::Path(crate::PinnedPathSpec {
+            path: Utf8TypedPathBuf::from("/workspace/recipes"),
+        });
+
+        // Build source is in /workspace/src (sibling of recipes)
+        let build_source = PinnedSourceSpec::Path(crate::PinnedPathSpec {
+            path: Utf8TypedPathBuf::from("/workspace/src"),
+        });
+
+        let record = SourceRecord {
+            package_record,
+            manifest_source: manifest_source.clone(),
+            build_source: Some(build_source),
+            input_hash: None,
+            sources: Default::default(),
+        };
+
+        // Convert to CondaPackageData (serialization)
+        let conda_source = record
+            .clone()
+            .into_conda_source_data(&std::path::PathBuf::from("/workspace"));
+
+        let package_build_source = conda_source
+            .package_build_source
+            .as_ref()
+            .expect("expected package build source");
+
+        let PackageBuildSource::Path { path } = package_build_source else {
+            panic!("expected path package build source");
+        };
+
+        // The path should now be relative to the manifest directory
+        // Manifest is in /workspace/recipes/, so ../src should point to /workspace/src
+        assert_eq!(
+            path.as_str(),
+            "../src",
+            "build_source should be relative to manifest_source directory"
+        );
+
+        // Convert back to SourceRecord (deserialization)
+        let roundtrip = SourceRecord::from_conda_source_data(
+            conda_source,
+            &std::path::PathBuf::from("/workspace"),
+        )
+        .expect("roundtrip should succeed");
+
+        let Some(PinnedSourceSpec::Path(roundtrip_path)) = roundtrip.build_source else {
+            panic!("expected path pinned source");
+        };
+
+        // After roundtrip, the path should remain as it was in the lock file (relative)
+        assert_eq!(
+            roundtrip_path.path.as_str(),
+            "../src",
+            "build_source should remain as relative path from lock file"
+        );
+    }
+
+    #[test]
+    fn package_build_source_path_stays_absolute_when_not_related() {
+        use typed_path::Utf8TypedPathBuf;
+
+        let package_record: PackageRecord = serde_json::from_value(json!({
+            "name": "example",
+            "version": "1.0.0",
+            "build": "0",
+            "build_number": 0,
+            "subdir": "noarch",
+        }))
+        .expect("valid package record");
+
+        // Manifest is in /workspace/recipes directory
+        let manifest_source = PinnedSourceSpec::Path(crate::PinnedPathSpec {
+            path: Utf8TypedPathBuf::from("/workspace/recipes"),
+        });
+
+        // Build source is in a completely different location
+        let build_source = PinnedSourceSpec::Path(crate::PinnedPathSpec {
+            path: Utf8TypedPathBuf::from("/completely/different/path"),
+        });
+
+        let record = SourceRecord {
+            package_record,
+            manifest_source: manifest_source.clone(),
+            build_source: Some(build_source),
+            input_hash: None,
+            sources: Default::default(),
+        };
+
+        // Convert to CondaPackageData (serialization)
+        let conda_source = record
+            .clone()
+            .into_conda_source_data(&std::path::PathBuf::from("/workspace"));
+
+        let package_build_source = conda_source
+            .package_build_source
+            .as_ref()
+            .expect("expected package build source");
+
+        let PackageBuildSource::Path { path } = package_build_source else {
+            panic!("expected path package build source");
+        };
+
+        // The path should be made relative
+        assert_eq!(path.as_str(), "../../completely/different/path");
+    }
+
+    #[test]
+    fn package_build_source_git_same_repo_is_made_relative() {
+        let package_record: PackageRecord = serde_json::from_value(json!({
+            "name": "example",
+            "version": "1.0.0",
+            "build": "0",
+            "build_number": 0,
+            "subdir": "noarch",
+        }))
+        .expect("valid package record");
+
+        let git_url = Url::parse("https://github.com/user/repo.git").unwrap();
+        let commit = GitSha::from_str("0123456789abcdef0123456789abcdef01234567").unwrap();
+
+        // Manifest is in recipes/ subdirectory
+        let manifest_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
+            git: git_url.clone(),
+            source: PinnedGitCheckout {
+                commit: commit.clone(),
+                subdirectory: Some("recipes".to_string()),
+                reference: GitReference::Branch("main".to_string()),
+            },
+        });
+
+        // Build source is in src/ subdirectory (sibling of recipes)
+        let build_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
+            git: git_url.clone(),
+            source: PinnedGitCheckout {
+                commit: commit.clone(),
+                subdirectory: Some("src".to_string()),
+                reference: GitReference::Branch("main".to_string()),
+            },
+        });
+
+        let record = SourceRecord {
+            package_record,
+            manifest_source: manifest_source.clone(),
+            build_source: Some(build_source),
+            input_hash: None,
+            sources: Default::default(),
+        };
+
+        // Convert to CondaPackageData (serialization)
+        let conda_source = record
+            .clone()
+            .into_conda_source_data(&std::path::PathBuf::from("/workspace"));
+
+        let package_build_source = conda_source
+            .package_build_source
+            .as_ref()
+            .expect("expected package build source");
+
+        let PackageBuildSource::Path { path } = package_build_source else {
+            panic!("expected path package build source (relativized from git)");
+        };
+
+        // The path should be relative: from recipes/ to src/ is ../src
+        assert_eq!(
+            path.as_str(),
+            "../src",
+            "build_source should be converted to relative path"
+        );
+
+        // Convert back to SourceRecord (deserialization)
+        let roundtrip = SourceRecord::from_conda_source_data(
+            conda_source,
+            &std::path::PathBuf::from("/workspace"),
+        )
+        .expect("roundtrip should succeed");
+
+        let Some(PinnedSourceSpec::Path(roundtrip_path)) = roundtrip.build_source else {
+            panic!("expected path pinned source after roundtrip (deserialized from relative path in lock file)");
+        };
+
+        // After roundtrip, it should remain as the relative path from the lock file
+        assert_eq!(roundtrip_path.path.as_str(), "../src");
+    }
+
+    #[test]
+    fn package_build_source_git_different_repos_stays_git() {
+        let package_record: PackageRecord = serde_json::from_value(json!({
+            "name": "example",
+            "version": "1.0.0",
+            "build": "0",
+            "build_number": 0,
+            "subdir": "noarch",
+        }))
+        .expect("valid package record");
+
+        let manifest_git_url = Url::parse("https://github.com/user/repo1.git").unwrap();
+        let build_git_url = Url::parse("https://github.com/user/repo2.git").unwrap();
+        let commit1 = GitSha::from_str("0123456789abcdef0123456789abcdef01234567").unwrap();
+        let commit2 = GitSha::from_str("abcdef0123456789abcdef0123456789abcdef01").unwrap();
+
+        // Manifest is in one repository
+        let manifest_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
+            git: manifest_git_url.clone(),
+            source: PinnedGitCheckout {
+                commit: commit1,
+                subdirectory: Some("recipes".to_string()),
+                reference: GitReference::Branch("main".to_string()),
+            },
+        });
+
+        // Build source is in a different repository
+        let build_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
+            git: build_git_url.clone(),
+            source: PinnedGitCheckout {
+                commit: commit2.clone(),
+                subdirectory: Some("src".to_string()),
+                reference: GitReference::Branch("main".to_string()),
+            },
+        });
+
+        let record = SourceRecord {
+            package_record,
+            manifest_source: manifest_source.clone(),
+            build_source: Some(build_source),
+            input_hash: None,
+            sources: Default::default(),
+        };
+
+        // Convert to CondaPackageData (serialization)
+        let conda_source = record
+            .clone()
+            .into_conda_source_data(&std::path::PathBuf::from("/workspace"));
+
+        let package_build_source = conda_source
+            .package_build_source
+            .as_ref()
+            .expect("expected package build source");
+
+        let PackageBuildSource::Git { url, subdir, .. } = package_build_source else {
+            panic!("expected git package build source (different repos should stay git)");
+        };
+
+        // Different repositories - should stay as Git source
+        assert_eq!(url, &build_git_url);
+        assert_eq!(subdir.as_ref().map(|s| s.as_str()), Some("src"));
+    }
 }

From 889ca9d1b477c59c57ecd3b56928fbb59dc54a23 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Thu, 6 Nov 2025 16:40:57 +0100
Subject: [PATCH 09/21] feat: correct round-trip conversion for build sources

---
 .../src/procedures/initialize.rs              |   4 +-
 .../src/build_backend_metadata/mod.rs         |   5 +-
 crates/pixi_core/src/lock_file/update.rs      |   4 +-
 crates/pixi_record/src/lib.rs                 |   5 +-
 crates/pixi_record/src/pinned_source.rs       | 275 ++++++++----------
 crates/pixi_record/src/source_record.rs       |  96 ++++--
 .../out-of-tree-source-parent/CMakeLists.txt  |   5 +
 .../out-of-tree-source-parent/main.cpp        |   6 +
 .../package/pixi.toml                         |   8 +
 .../out-of-tree-source-parent/pixi.lock       |  81 ++++++
 .../out-of-tree-source-parent/pixi.toml       |  10 +
 .../out-of-tree-source/pixi.lock              |   2 +-
 12 files changed, 309 insertions(+), 192 deletions(-)
 create mode 100644 tests/data/satisfiability/out-of-tree-source-parent/CMakeLists.txt
 create mode 100644 tests/data/satisfiability/out-of-tree-source-parent/main.cpp
 create mode 100644 tests/data/satisfiability/out-of-tree-source-parent/package/pixi.toml
 create mode 100644 tests/data/satisfiability/out-of-tree-source-parent/pixi.lock
 create mode 100644 tests/data/satisfiability/out-of-tree-source-parent/pixi.toml

diff --git a/crates/pixi_build_types/src/procedures/initialize.rs b/crates/pixi_build_types/src/procedures/initialize.rs
index acaa8f244b..eb43fb4442 100644
--- a/crates/pixi_build_types/src/procedures/initialize.rs
+++ b/crates/pixi_build_types/src/procedures/initialize.rs
@@ -27,14 +27,14 @@ pub const METHOD_NAME: &str = "initialize";
 pub struct InitializeParams {
     /// The manifest that the build backend should use.
     ///
-    /// This is an absolute path.
+    /// This is an absolute path to a manifest file.
     pub manifest_path: PathBuf,
 
     /// The root directory of the source code that the build backend should use.
     /// If this is `None`, the backend should use the directory of the
     /// `manifest_path` as the source directory.
     ///
-    /// This is an absolute path.
+    /// This is an absolute path. This is always a directory.
     pub source_dir: Option<PathBuf>,
 
     /// The root directory of the workspace.
diff --git a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
index cc5593b078..02f1f448d0 100644
--- a/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
+++ b/crates/pixi_command_dispatcher/src/build_backend_metadata/mod.rs
@@ -135,11 +135,12 @@ impl BuildBackendMetadataSpec {
         // Determine the location of the source to build from.
         let manifest_source_anchor =
             SourceAnchor::from(SourceSpec::from(self.manifest_source.clone()));
+        // `build_source` is still relative to the `manifest_source`
         let build_source_checkout = match &discovered_backend.init_params.build_source {
             None => None,
-            Some(spec) => {
+            Some(build_source) => {
                 // An out of tree source is provided. Resolve it against the manifest source.
-                let resolved_location = manifest_source_anchor.resolve(spec.clone());
+                let resolved_location = manifest_source_anchor.resolve(build_source.clone());
                 let resolved_source_build_spec = SourceSpec {
                     location: resolved_location.clone(),
                 };
diff --git a/crates/pixi_core/src/lock_file/update.rs b/crates/pixi_core/src/lock_file/update.rs
index 9d0bd41f55..005e45187e 100644
--- a/crates/pixi_core/src/lock_file/update.rs
+++ b/crates/pixi_core/src/lock_file/update.rs
@@ -1146,7 +1146,9 @@ impl<'p> UpdateContextBuilder<'p> {
                             .map(|(platform, records)| {
                                 records
                                     .cloned()
-                                    .map(|data| PixiRecord::from_conda_package_data(data, workspace_root))
+                                    .map(|data| {
+                                        PixiRecord::from_conda_package_data(data, workspace_root)
+                                    })
                                     .collect::<Result<Vec<_>, _>>()
                                     .map(|records| {
                                         (platform, Arc::new(PixiRecordsByName::from_iter(records)))
diff --git a/crates/pixi_record/src/lib.rs b/crates/pixi_record/src/lib.rs
index d9e0928b1b..cf65141fd3 100644
--- a/crates/pixi_record/src/lib.rs
+++ b/crates/pixi_record/src/lib.rs
@@ -40,10 +40,7 @@ impl PixiRecord {
 
     /// Convert to CondaPackageData with paths made relative to workspace_root.
     /// This should be used when writing to the lock file.
-    pub fn into_conda_package_data(
-        self,
-        workspace_root: &std::path::Path,
-    ) -> CondaPackageData {
+    pub fn into_conda_package_data(self, workspace_root: &std::path::Path) -> CondaPackageData {
         match self {
             PixiRecord::Binary(record) => record.into(),
             PixiRecord::Source(record) => {
diff --git a/crates/pixi_record/src/pinned_source.rs b/crates/pixi_record/src/pinned_source.rs
index 759e5c49b3..eaf1b7e486 100644
--- a/crates/pixi_record/src/pinned_source.rs
+++ b/crates/pixi_record/src/pinned_source.rs
@@ -223,18 +223,18 @@ impl PinnedSourceSpec {
     ///
     /// # Arguments
     /// * `base` - The base pinned source to make this path relative to (typically the manifest_source)
-    pub fn make_relative_to(&self, base: &PinnedSourceSpec) -> Option<Self> {
-        use pixi_git::url::RepositoryUrl;
-        use typed_path::{Utf8Component, Utf8UnixPath};
-
+    pub fn make_relative_to(&self, base: &PinnedSourceSpec, workspace_root: &Path) -> Option<Self> {
         match (self, base) {
             // Path-to-Path: Make the path relative
             (PinnedSourceSpec::Path(this_path), PinnedSourceSpec::Path(base_path)) => {
-                // Base path is a directory (not a file path)
-                // Create a temporary Path for the base directory
-                let base_dir = Path::new(base_path.path.as_str());
+                let this_path = this_path.resolve(workspace_root);
+                let base_path = base_path.resolve(workspace_root);
+
+                let relative_path = pathdiff::diff_paths(this_path, base_path)?;
 
-                Some(PinnedSourceSpec::Path(this_path.make_relative_to(base_dir)))
+                Some(PinnedSourceSpec::Path(PinnedPathSpec {
+                    path: Utf8TypedPathBuf::from(relative_path.to_string_lossy().as_ref()),
+                }))
             }
             // Git-to-Git: If same repository, convert to a relative path based on subdirectories
             (PinnedSourceSpec::Git(this_git), PinnedSourceSpec::Git(base_git)) => {
@@ -247,58 +247,30 @@ impl PinnedSourceSpec {
                     return None;
                 }
 
-                // Same repository - compute relative path between subdirectories
-                let base_subdir = base_git.source.subdirectory.as_deref().unwrap_or("");
-                let this_subdir = this_git.source.subdirectory.as_deref().unwrap_or("");
-
-                // If both point to the same subdirectory, don't relativize (keep as Git)
-                if base_subdir == this_subdir {
+                if this_git.source.commit != base_git.source.commit {
                     return None;
                 }
 
-                // Always use Unix-style paths for Git subdirectories
-                let base_unix = Utf8UnixPath::new(base_subdir);
-                let this_unix = Utf8UnixPath::new(this_subdir);
-
-                // Try to compute relative path
-                if let Ok(rel) = this_unix.strip_prefix(base_unix) {
-                    // this_subdir is under base_subdir
-                    Some(PinnedSourceSpec::Path(PinnedPathSpec {
-                        path: rel.as_str().into(),
-                    }))
-                } else {
-                    // Need to compute relative path using .. components
-                    let base_components: Vec<_> = base_unix.components().collect();
-                    let this_components: Vec<_> = this_unix.components().collect();
-
-                    // Find common prefix
-                    let common = base_components
-                        .iter()
-                        .zip(this_components.iter())
-                        .take_while(|(a, b)| a == b)
-                        .count();
-
-                    // Build relative path: go up from base, then down to target
-                    let ups = base_components.len() - common;
-                    let mut rel_path = String::new();
-                    for _ in 0..ups {
-                        if !rel_path.is_empty() {
-                            rel_path.push('/');
-                        }
-                        rel_path.push_str("..");
-                    }
-                    for comp in &this_components[common..] {
-                        if !rel_path.is_empty() {
-                            rel_path.push('/');
-                        }
-                        rel_path.push_str(comp.as_str());
-                    }
+                // bas = { git = "ssh@tim", subdir = "baz" }
+                //
+                // [package.build]
+                // source = foo/bar
+                //
 
-                    Some(PinnedSourceSpec::Path(PinnedPathSpec {
-                        path: rel_path.into(),
-                    }))
-                }
+                // Same repository - compute relative path between subdirectories
+                //  baz
+                let base_subdir = base_git.source.subdirectory.as_deref().unwrap_or("");
+                // baz/foo/bar
+                let this_subdir = this_git.source.subdirectory.as_deref().unwrap_or("");
+
+                //foo/bar
+                let relative_path = pathdiff::diff_paths(this_subdir, base_subdir)?;
+                Some(PinnedSourceSpec::Path(PinnedPathSpec {
+                    path: Utf8TypedPathBuf::from(relative_path.to_string_lossy().as_ref()),
+                }))
             }
+            (PinnedSourceSpec::Url(_), _) => unreachable!("url specs have not been implemented"),
+            (_, PinnedSourceSpec::Url(_)) => unreachable!("url specs have not been implemented"),
             // Different types or incompatible sources
             _ => None,
         }
@@ -546,111 +518,12 @@ pub struct PinnedPathSpec {
 
 impl PinnedPathSpec {
     /// Resolves the path to an absolute path.
-    pub fn resolve(&self, project_root: &Path) -> PathBuf {
+    pub fn resolve(&self, workspace_root: &Path) -> PathBuf {
         let native_path = Path::new(self.path.as_str());
         if native_path.is_absolute() {
             native_path.to_path_buf()
         } else {
-            project_root.join(native_path)
-        }
-    }
-
-    /// Makes this path relative to another path if possible.
-    /// If the path is already relative or cannot be made relative, returns self unchanged.
-    ///
-    /// # Arguments
-    /// * `base` - The base path to make this path relative to
-    pub fn make_relative_to(&self, base: &Path) -> Self {
-        use typed_path::{Utf8Component, Utf8UnixPath, Utf8WindowsPath};
-
-        // Check if the path is already relative
-        let is_relative = if self.path.as_str().starts_with('/') {
-            // Unix absolute path
-            false
-        } else if self.path.as_str().len() >= 2 && self.path.as_str().chars().nth(1) == Some(':') {
-            // Windows absolute path (C:\...)
-            false
-        } else {
-            // Relative path
-            true
-        };
-
-        if is_relative {
-            return self.clone();
-        }
-
-        // Convert base to string for comparison
-        let base_str = base.to_string_lossy();
-
-        // Determine if we're working with Unix or Windows paths
-        let is_unix_style = self.path.as_str().starts_with('/');
-
-        if is_unix_style {
-            // Use Unix path logic
-            let this_unix = Utf8UnixPath::new(self.path.as_str());
-            let base_unix = Utf8UnixPath::new(&base_str);
-
-            if let Ok(rel) = this_unix.strip_prefix(base_unix) {
-                Self {
-                    path: rel.as_str().into(),
-                }
-            } else {
-                // Try using pathdiff for more complex relativization
-                let this_components: Vec<_> = this_unix.components().collect();
-                let base_components: Vec<_> = base_unix.components().collect();
-
-                // Find common prefix
-                let common = this_components
-                    .iter()
-                    .zip(base_components.iter())
-                    .take_while(|(a, b)| a == b)
-                    .count();
-
-                if common == 0 {
-                    // No common prefix, keep absolute
-                    return self.clone();
-                }
-
-                // Build relative path: go up from base, then down to target
-                let ups = base_components.len() - common;
-                let mut rel_path = String::new();
-                for _ in 0..ups {
-                    if !rel_path.is_empty() {
-                        rel_path.push('/');
-                    }
-                    rel_path.push_str("..");
-                }
-                for comp in &this_components[common..] {
-                    if !rel_path.is_empty() {
-                        rel_path.push('/');
-                    }
-                    rel_path.push_str(comp.as_str());
-                }
-
-                Self {
-                    path: rel_path.into(),
-                }
-            }
-        } else {
-            // Use Windows path logic
-            let this_windows = Utf8WindowsPath::new(self.path.as_str());
-            let base_windows = Utf8WindowsPath::new(&base_str);
-
-            if let Ok(rel) = this_windows.strip_prefix(base_windows) {
-                Self {
-                    path: rel.as_str().into(),
-                }
-            } else {
-                // For Windows, fall back to pathdiff with native paths
-                let native_path = Path::new(self.path.as_str());
-                if let Some(relative_path) = pathdiff::diff_paths(native_path, base) {
-                    Self {
-                        path: relative_path.to_string_lossy().to_string().into(),
-                    }
-                } else {
-                    self.clone()
-                }
-            }
+            workspace_root.join(native_path)
         }
     }
 
@@ -1625,4 +1498,94 @@ mod tests {
             assert!(pinned.matches_source_spec(&spec));
         }
     }
+
+    mod make_relative_to {
+        use std::path::Path;
+
+        use crate::{PinnedPathSpec, PinnedSourceSpec};
+
+        #[test]
+        fn test_relative_to_relative() {
+            // Both paths are relative - after resolution they become absolute, then relative path is computed
+            let workspace_root = Path::new("/workspace");
+
+            let this_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "foo/bar".into(),
+            });
+            let base_spec = PinnedSourceSpec::Path(PinnedPathSpec { path: "foo".into() });
+
+            let result = this_spec.make_relative_to(&base_spec, workspace_root);
+
+            // Both resolve to /workspace/foo/bar and /workspace/foo
+            // Relative path should be "bar"
+            let PinnedSourceSpec::Path(path) = result.expect("Should return Some") else {
+                panic!("Expected Path variant");
+            };
+            assert_eq!(path.path.as_str(), "bar");
+        }
+
+        #[test]
+        fn test_absolute_to_absolute() {
+            // Both paths are absolute
+            let workspace_root = Path::new("/workspace");
+
+            let this_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "/foo/bar/baz".into(),
+            });
+            let base_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "/foo/bar".into(),
+            });
+
+            let result = this_spec.make_relative_to(&base_spec, workspace_root);
+
+            // Should compute relative path
+            let PinnedSourceSpec::Path(path) = result.expect("Should return Some") else {
+                panic!("Expected Path variant");
+            };
+            assert_eq!(path.path.as_str(), "baz");
+        }
+
+        #[test]
+        fn test_relative_to_absolute() {
+            // Self is relative, base is absolute - after resolution they're both absolute
+            let workspace_root = Path::new("/workspace");
+
+            let this_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "foo/bar".into(), // Resolves to /workspace/foo/bar
+            });
+            let base_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "/other/path".into(), // Already absolute
+            });
+
+            let result = this_spec.make_relative_to(&base_spec, workspace_root);
+
+            // Both are absolute after resolution, pathdiff should compute relative path
+            let PinnedSourceSpec::Path(path) = result.expect("Should return Some") else {
+                panic!("Expected Path variant");
+            };
+            // From /other/path to /workspace/foo/bar
+            assert_eq!(path.path.as_str(), "../../workspace/foo/bar");
+        }
+
+        #[test]
+        fn test_absolute_with_parent_navigation() {
+            // Test paths that require .. navigation
+            let workspace_root = Path::new("/workspace");
+
+            let this_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "/foo/bar/qux".into(),
+            });
+            let base_spec = PinnedSourceSpec::Path(PinnedPathSpec {
+                path: "/foo/baz/quux".into(),
+            });
+
+            let result = this_spec.make_relative_to(&base_spec, workspace_root);
+
+            let PinnedSourceSpec::Path(path) = result.expect("Should return Some") else {
+                panic!("Expected Path variant");
+            };
+            // From /foo/baz/quux to /foo/bar/qux requires ../../bar/qux
+            assert_eq!(path.path.as_str(), "../../bar/qux");
+        }
+    }
 }
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index 99502aa7d3..b28943e45e 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -1,5 +1,6 @@
 use std::{
     collections::{BTreeSet, HashMap},
+    path::Path,
     str::FromStr,
 };
 
@@ -24,7 +25,8 @@ pub struct SourceRecord {
     pub manifest_source: PinnedSourceSpec,
 
     /// The optional pinned source where the build should be executed
-    /// This is used when the manifest is not in the same location ad
+    /// This is used when the manifest is not in the same location as the
+    /// source files.
     pub build_source: Option<PinnedSourceSpec>,
 
     /// The hash of the input that was used to build the metadata of the
@@ -56,21 +58,17 @@ pub struct InputHash {
 }
 
 impl SourceRecord {
-    /// Convert to CondaSourceData with paths made relative to workspace_root.
+    /// Convert [`SourceRecord`] into lock-file compatible `CondaSourceData`
+    /// The `build_source` in the SourceRecord is always relative to the workspace.
+    /// However, when saving in the lock-file make these relative to the package manifest.
     /// This should be used when writing to the lock file.
-    ///
-    /// TODO: Currently this doesn't use workspace_root and just makes build_source
-    /// relative to manifest_source. Future implementation should make both relative
-    /// to workspace_root first.
-    pub fn into_conda_source_data(
-        self,
-        _workspace_root: &std::path::Path,
-    ) -> CondaSourceData {
-        let package_build_source = self.build_source.map(|s| {
-            // Try to make build_source relative to manifest_source
-            let s = s.make_relative_to(&self.manifest_source).unwrap_or(s);
-
-            match s {
+    pub fn into_conda_source_data(self, workspace_root: &Path) -> CondaSourceData {
+        let package_build_source = self.build_source.map(|build_source| {
+            let pinned_source_spec = build_source
+                .make_relative_to(&self.manifest_source, workspace_root)
+                .unwrap_or(build_source);
+
+            match pinned_source_spec {
                 PinnedSourceSpec::Url(pinned_url_spec) => PackageBuildSource::Url {
                     url: pinned_url_spec.url,
                     sha256: pinned_url_spec.sha256,
@@ -124,17 +122,16 @@ impl SourceRecord {
     /// Create SourceRecord from CondaSourceData with paths resolved relative to workspace_root.
     /// This should be used when reading from the lock file.
     ///
-    /// TODO: Currently this doesn't use workspace_root and just resolves build_source
-    /// relative to manifest_source. Future implementation should resolve both against
-    /// workspace_root first.
+    /// The inverse of `into_conda_source_data`:
+    /// - manifest_source: relative to workspace_root (or absolute) → resolve to absolute
+    /// - build_source: relative to manifest_source (or absolute) → resolve to absolute
     pub fn from_conda_source_data(
         data: CondaSourceData,
-        _workspace_root: &std::path::Path,
+        workspace_root: &std::path::Path,
     ) -> Result<Self, ParseLockFileError> {
-
         let manifest_source: PinnedSourceSpec = data.location.try_into()?;
 
-        let pinned_source_spec = data.package_build_source.map(|source| match source {
+        let build_source = data.package_build_source.map(|source| match source {
             PackageBuildSource::Git {
                 url,
                 spec,
@@ -148,6 +145,7 @@ impl SourceRecord {
                     None => GitReference::DefaultBranch,
                 };
 
+                // Out-of-tree git repository
                 PinnedSourceSpec::Git(crate::PinnedGitSpec {
                     git: url,
                     source: PinnedGitCheckout {
@@ -167,9 +165,53 @@ impl SourceRecord {
                 md5: None,
             }),
             PackageBuildSource::Path { path } => {
-                // Keep paths as-is from the lock file
-                // They will be resolved later by the code that uses them
-                PinnedSourceSpec::Path(crate::PinnedPathSpec { path })
+                if path.is_absolute() {
+                    crate::PinnedSourceSpec::Path(crate::PinnedPathSpec { path })
+                } else {
+                    match &manifest_source {
+                        PinnedSourceSpec::Url(_) => unimplemented!(),
+                        PinnedSourceSpec::Git(pinned_git_spec) => {
+                            let base_dir = pinned_git_spec.source.subdirectory.as_ref();
+                            // Make `path` relative to repository root, if `base` is not None it will
+                            // be relative with `base` at this point, so lets join
+                            let subdir =
+                                base_dir.map(|base| Path::new(base).join(Path::new(path.as_str())));
+
+                            let mut git_source = pinned_git_spec.source.clone();
+                            git_source.subdirectory =
+                                subdir.map(|p| p.to_string_lossy().to_string());
+
+                            // Reconstruct the git object
+                            PinnedSourceSpec::Git(crate::PinnedGitSpec {
+                                git: pinned_git_spec.git.clone(),
+                                source: git_source,
+                            })
+                        }
+                        PinnedSourceSpec::Path(manifest_path) => {
+                            // path is relative to manifest_source (or absolute) in the lock file
+                            // We need to make it relative to workspace_root (or keep it absolute)
+                            let build_source_spec = crate::PinnedPathSpec { path };
+
+                            // If path is relative, it's relative to manifest_source
+                            // First resolve manifest_source against workspace_root
+                            // Then resolve path against the resolved manifest_source
+                            // Finally make the result relative to workspace_root
+                            let manifest_absolute = manifest_path.resolve(workspace_root);
+                            let build_absolute = build_source_spec.resolve(&manifest_absolute);
+
+                            // Make the normalized path relative to workspace_root
+                            let relative_to_workspace =
+                                pathdiff::diff_paths(&build_absolute, workspace_root)
+                                    .unwrap_or_else(|| build_absolute);
+
+                            PinnedSourceSpec::Path(crate::PinnedPathSpec {
+                                path: Utf8TypedPathBuf::from(
+                                    relative_to_workspace.to_string_lossy().as_ref(),
+                                ),
+                            })
+                        }
+                    }
+                }
             }
         });
 
@@ -180,7 +222,7 @@ impl SourceRecord {
                 hash: hash.hash,
                 globs: BTreeSet::from_iter(hash.globs),
             }),
-            build_source: pinned_source_spec,
+            build_source,
             sources: data
                 .sources
                 .into_iter()
@@ -497,7 +539,9 @@ mod tests {
         .expect("roundtrip should succeed");
 
         let Some(PinnedSourceSpec::Path(roundtrip_path)) = roundtrip.build_source else {
-            panic!("expected path pinned source after roundtrip (deserialized from relative path in lock file)");
+            panic!(
+                "expected path pinned source after roundtrip (deserialized from relative path in lock file)"
+            );
         };
 
         // After roundtrip, it should remain as the relative path from the lock file
diff --git a/tests/data/satisfiability/out-of-tree-source-parent/CMakeLists.txt b/tests/data/satisfiability/out-of-tree-source-parent/CMakeLists.txt
new file mode 100644
index 0000000000..5ff26babb6
--- /dev/null
+++ b/tests/data/satisfiability/out-of-tree-source-parent/CMakeLists.txt
@@ -0,0 +1,5 @@
+cmake_minimum_required(VERSION 3.10)
+project(out-of-tree-package)
+
+# Simple test project for out-of-tree builds
+add_executable(test_app main.cpp)
diff --git a/tests/data/satisfiability/out-of-tree-source-parent/main.cpp b/tests/data/satisfiability/out-of-tree-source-parent/main.cpp
new file mode 100644
index 0000000000..67610f5bfd
--- /dev/null
+++ b/tests/data/satisfiability/out-of-tree-source-parent/main.cpp
@@ -0,0 +1,6 @@
+#include <iostream>
+
+int main() {
+    std::cout << "Hello from out-of-tree build!" << std::endl;
+    return 0;
+}
diff --git a/tests/data/satisfiability/out-of-tree-source-parent/package/pixi.toml b/tests/data/satisfiability/out-of-tree-source-parent/package/pixi.toml
new file mode 100644
index 0000000000..d75fbd81c9
--- /dev/null
+++ b/tests/data/satisfiability/out-of-tree-source-parent/package/pixi.toml
@@ -0,0 +1,8 @@
+[package]
+name = "out-of-tree-package"
+version = "0.1.0"
+
+[package.build]
+backend = { name = "pixi-build-cmake", version = "0.3.*" }
+# Point to source files in a different directory (out-of-tree build)
+source = { path = "../" }
diff --git a/tests/data/satisfiability/out-of-tree-source-parent/pixi.lock b/tests/data/satisfiability/out-of-tree-source-parent/pixi.lock
new file mode 100644
index 0000000000..0e42219605
--- /dev/null
+++ b/tests/data/satisfiability/out-of-tree-source-parent/pixi.lock
@@ -0,0 +1,81 @@
+version: 6
+environments:
+  default:
+    channels:
+    - url: https://prefix.dev/pixi-build-backends/
+    - url: https://prefix.dev/conda-forge/
+    packages:
+      linux-64:
+      - conda: https://prefix.dev/conda-forge/linux-64/_libgcc_mutex-0.1-conda_forge.tar.bz2
+      - conda: https://prefix.dev/conda-forge/linux-64/_openmp_mutex-4.5-2_gnu.tar.bz2
+      - conda: https://prefix.dev/conda-forge/linux-64/libgcc-15.2.0-h767d61c_7.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/libgomp-15.2.0-h767d61c_7.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/libstdcxx-15.2.0-h8f9b012_7.conda
+      - conda: ./package
+packages:
+- conda: https://prefix.dev/conda-forge/linux-64/_libgcc_mutex-0.1-conda_forge.tar.bz2
+  sha256: fe51de6107f9edc7aa4f786a70f4a883943bc9d39b3bb7307c04c41410990726
+  md5: d7c89558ba9fa0495403155b64376d81
+  license: None
+  size: 2562
+  timestamp: 1578324546067
+- conda: https://prefix.dev/conda-forge/linux-64/_openmp_mutex-4.5-2_gnu.tar.bz2
+  build_number: 16
+  sha256: fbe2c5e56a653bebb982eda4876a9178aedfc2b545f25d0ce9c4c0b508253d22
+  md5: 73aaf86a425cc6e73fcf236a5a46396d
+  depends:
+  - _libgcc_mutex 0.1 conda_forge
+  - libgomp >=7.5.0
+  constrains:
+  - openmp_impl 9999
+  license: BSD-3-Clause
+  license_family: BSD
+  size: 23621
+  timestamp: 1650670423406
+- conda: https://prefix.dev/conda-forge/linux-64/libgcc-15.2.0-h767d61c_7.conda
+  sha256: 08f9b87578ab981c7713e4e6a7d935e40766e10691732bba376d4964562bcb45
+  md5: c0374badb3a5d4b1372db28d19462c53
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  - _openmp_mutex >=4.5
+  constrains:
+  - libgomp 15.2.0 h767d61c_7
+  - libgcc-ng ==15.2.0=*_7
+  license: GPL-3.0-only WITH GCC-exception-3.1
+  license_family: GPL
+  size: 822552
+  timestamp: 1759968052178
+- conda: https://prefix.dev/conda-forge/linux-64/libgomp-15.2.0-h767d61c_7.conda
+  sha256: e9fb1c258c8e66ee278397b5822692527c5f5786d372fe7a869b900853f3f5ca
+  md5: f7b4d76975aac7e5d9e6ad13845f92fe
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  license: GPL-3.0-only WITH GCC-exception-3.1
+  license_family: GPL
+  size: 447919
+  timestamp: 1759967942498
+- conda: https://prefix.dev/conda-forge/linux-64/libstdcxx-15.2.0-h8f9b012_7.conda
+  sha256: 1b981647d9775e1cdeb2fab0a4dd9cd75a6b0de2963f6c3953dbd712f78334b3
+  md5: 5b767048b1b3ee9a954b06f4084f93dc
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  - libgcc 15.2.0 h767d61c_7
+  constrains:
+  - libstdcxx-ng ==15.2.0=*_7
+  license: GPL-3.0-only WITH GCC-exception-3.1
+  license_family: GPL
+  size: 3898269
+  timestamp: 1759968103436
+- conda: ./package
+  name: out-of-tree-package
+  version: 0.1.0
+  build: hb0f4dca_0
+  subdir: linux-64
+  depends:
+  - libstdcxx >=15
+  - libgcc >=15
+  input:
+    hash: 616e7d8611fa803e6655c354f183d6f4b405e94adcabc83c260d8b9da5e3c9d8
+    globs: []
+  package_build_source:
+    path: ..
diff --git a/tests/data/satisfiability/out-of-tree-source-parent/pixi.toml b/tests/data/satisfiability/out-of-tree-source-parent/pixi.toml
new file mode 100644
index 0000000000..e319b11972
--- /dev/null
+++ b/tests/data/satisfiability/out-of-tree-source-parent/pixi.toml
@@ -0,0 +1,10 @@
+[workspace]
+channels = [
+  "https://prefix.dev/pixi-build-backends",
+  "https://prefix.dev/conda-forge",
+]
+platforms = ["linux-64"]
+preview = ["pixi-build"]
+
+[dependencies]
+out-of-tree-package = { path = "./package" }
diff --git a/tests/data/satisfiability/out-of-tree-source/pixi.lock b/tests/data/satisfiability/out-of-tree-source/pixi.lock
index f0d728af97..473a6559f3 100644
--- a/tests/data/satisfiability/out-of-tree-source/pixi.lock
+++ b/tests/data/satisfiability/out-of-tree-source/pixi.lock
@@ -69,7 +69,7 @@ packages:
 - conda: build-config
   name: out-of-tree-package
   version: 0.1.0
-  build: hbf21a9e_0
+  build: hb0f4dca_0
   subdir: linux-64
   depends:
   - libstdcxx >=15

From eaa6edda755db0d68e1e0e4559fb30d958526408 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 09:35:27 +0100
Subject: [PATCH 10/21] fix: clippy

---
 crates/pixi_record/src/source_record.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index b28943e45e..b39d0ed900 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -202,7 +202,7 @@ impl SourceRecord {
                             // Make the normalized path relative to workspace_root
                             let relative_to_workspace =
                                 pathdiff::diff_paths(&build_absolute, workspace_root)
-                                    .unwrap_or_else(|| build_absolute);
+                                    .unwrap_or(build_absolute);
 
                             PinnedSourceSpec::Path(crate::PinnedPathSpec {
                                 path: Utf8TypedPathBuf::from(
@@ -486,7 +486,7 @@ mod tests {
         let manifest_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
             git: git_url.clone(),
             source: PinnedGitCheckout {
-                commit: commit.clone(),
+                commit: commit,
                 subdirectory: Some("recipes".to_string()),
                 reference: GitReference::Branch("main".to_string()),
             },
@@ -496,7 +496,7 @@ mod tests {
         let build_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
             git: git_url.clone(),
             source: PinnedGitCheckout {
-                commit: commit.clone(),
+                commit: commit,
                 subdirectory: Some("src".to_string()),
                 reference: GitReference::Branch("main".to_string()),
             },
@@ -578,7 +578,7 @@ mod tests {
         let build_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
             git: build_git_url.clone(),
             source: PinnedGitCheckout {
-                commit: commit2.clone(),
+                commit: commit2,
                 subdirectory: Some("src".to_string()),
                 reference: GitReference::Branch("main".to_string()),
             },

From 903cd3b890d58a5d16c2165569118146f9dccca9 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 12:00:01 +0100
Subject: [PATCH 11/21] added roundtrip snapshot test and fix

---
 Cargo.lock                                    |  2 +
 .../src/lock_file/satisfiability/mod.rs       |  8 +---
 crates/pixi_record/Cargo.toml                 |  2 +
 ...d__tests__roundtrip_conda_source_data.snap | 39 +++++++++++++++++++
 crates/pixi_record/src/source_record.rs       | 30 +++++++++++++-
 crates/pixi_spec/src/lib.rs                   |  4 +-
 crates/pixi_spec/src/url.rs                   |  2 +-
 7 files changed, 76 insertions(+), 11 deletions(-)
 create mode 100644 crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap

diff --git a/Cargo.lock b/Cargo.lock
index 6f839e8d02..b66b6d2f10 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5296,6 +5296,7 @@ name = "pixi_record"
 version = "0.1.0"
 dependencies = [
  "file_url",
+ "insta",
  "miette 7.6.0",
  "pathdiff",
  "pixi_git",
@@ -5306,6 +5307,7 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_with",
+ "serde_yaml",
  "thiserror 2.0.17",
  "typed-path",
  "url",
diff --git a/crates/pixi_core/src/lock_file/satisfiability/mod.rs b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
index d5477e716f..19da02d82b 100644
--- a/crates/pixi_core/src/lock_file/satisfiability/mod.rs
+++ b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
@@ -1508,14 +1508,8 @@ pub(crate) async fn verify_package_platform_satisfiability(
                 continue;
             };
 
-            // Get the manifest directory first
-            let Some(manifest_path_record) = source_record.manifest_source.as_path() else {
-                continue;
-            };
-            let manifest_dir = manifest_path_record.resolve(project_root);
-
             // Resolve build_source relative to the manifest directory
-            build_path_record.resolve(&manifest_dir)
+            build_path_record.resolve(&project_root)
         } else {
             let Some(path_record) = source_record.manifest_source.as_path() else {
                 continue;
diff --git a/crates/pixi_record/Cargo.toml b/crates/pixi_record/Cargo.toml
index 92e3657806..8e3c8c2a5a 100644
--- a/crates/pixi_record/Cargo.toml
+++ b/crates/pixi_record/Cargo.toml
@@ -25,4 +25,6 @@ typed-path = { workspace = true }
 url = { workspace = true }
 
 [dev-dependencies]
+insta = { workspace = true, features = ["yaml"] }
 serde_json = { workspace = true }
+serde_yaml = { workspace = true }
diff --git a/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap b/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
new file mode 100644
index 0000000000..aff2185125
--- /dev/null
+++ b/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
@@ -0,0 +1,39 @@
+---
+source: crates/pixi_record/src/source_record.rs
+expression: roundtrip
+---
+package_record:
+  build: h123456_0
+  build_number: 0
+  depends: []
+  md5: d41d8cd98f00b204e9800998ecf8427e
+  name: comprehensive-test
+  sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+  subdir: noarch
+  version: 1.0.0
+manifest_source:
+  commit: abc123def456abc123def456abc123def456abc1
+  git: "https://github.com/example/mono-repo.git"
+  reference:
+    branch: main
+  subdirectory: recipes
+build_source:
+  commit: abc123def456abc123def456abc123def456abc1
+  git: "https://github.com/example/mono-repo.git"
+  reference:
+    branch: main
+  subdirectory: recipes/nested/src
+input_hash:
+  hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+  globs:
+    - "**/*.py"
+    - "**/*.txt"
+sources:
+  git-dep:
+    location:
+      git: "https://github.com/example/dep.git"
+      subdirectory: python
+      tag: v1.0.0
+  path-dep:
+    location:
+      path: "../vendor"
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index b39d0ed900..ea732fedd7 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -15,7 +15,7 @@ use typed_path::Utf8TypedPathBuf;
 use crate::{ParseLockFileError, PinnedGitCheckout, PinnedSourceSpec};
 
 /// A record of a conda package that still requires building.
-#[derive(Debug, Clone, serde::Serialize)]
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct SourceRecord {
     /// Information about the conda package. This is metadata of the package
     /// after it has been build.
@@ -610,4 +610,32 @@ mod tests {
         assert_eq!(url, &build_git_url);
         assert_eq!(subdir.as_ref().map(|s| s.as_str()), Some("src"));
     }
+
+    #[test]
+    fn roundtrip_conda_source_data() {
+        let workspace_root = std::path::Path::new("/workspace");
+
+        // Load the SourceRecord from snapshot (skip YAML frontmatter)
+        let snapshot_content = include_str!(
+            "snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap"
+        );
+        let yaml_content = snapshot_content
+            .split("---")
+            .nth(2)
+            .expect("snapshot should have YAML content");
+        let original: SourceRecord =
+            serde_yaml::from_str(yaml_content).expect("failed to load snapshot");
+
+        // Roundtrip: SourceRecord -> CondaSourceData -> SourceRecord
+        let conda_data = original.clone().into_conda_source_data(workspace_root);
+        let roundtrip = SourceRecord::from_conda_source_data(conda_data, workspace_root)
+            .expect("from_conda_source_data should succeed");
+
+        // Snapshot the final result - should match the original
+        let mut settings = insta::Settings::clone_current();
+        settings.set_sort_maps(true);
+        settings.bind(|| {
+            insta::assert_yaml_snapshot!(roundtrip);
+        });
+    }
 }
diff --git a/crates/pixi_spec/src/lib.rs b/crates/pixi_spec/src/lib.rs
index 940d4922fe..7f0ca5aec0 100644
--- a/crates/pixi_spec/src/lib.rs
+++ b/crates/pixi_spec/src/lib.rs
@@ -362,14 +362,14 @@ impl PixiSpec {
 ///
 /// This type only represents source packages. Use [`PixiSpec`] to represent
 /// both binary and source packages.
-#[derive(Debug, Clone, Hash, PartialEq, Eq, serde::Serialize)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 pub struct SourceSpec {
     /// The location of the source.
     pub location: SourceLocationSpec,
 }
 
 /// A specification for a source location.
-#[derive(Debug, Clone, Hash, PartialEq, Eq, serde::Serialize)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[serde(untagged)]
 pub enum SourceLocationSpec {
     /// The spec is represented as an archive that can be downloaded from the
diff --git a/crates/pixi_spec/src/url.rs b/crates/pixi_spec/src/url.rs
index 3a47aade01..96b7732dc4 100644
--- a/crates/pixi_spec/src/url.rs
+++ b/crates/pixi_spec/src/url.rs
@@ -97,7 +97,7 @@ impl Display for UrlSpec {
 
 /// A specification of a source archive from a URL.
 #[serde_as]
-#[derive(Debug, Clone, Hash, Eq, PartialEq, serde::Serialize)]
+#[derive(Debug, Clone, Hash, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
 pub struct UrlSourceSpec {
     /// The URL of the package
     pub url: Url,

From 407eff280c8a7a0990877e8573729b1078c4bedc Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 12:08:23 +0100
Subject: [PATCH 12/21] fix: clippy

---
 crates/pixi_record/src/source_record.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index ea732fedd7..b51b4e4c30 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -486,7 +486,7 @@ mod tests {
         let manifest_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
             git: git_url.clone(),
             source: PinnedGitCheckout {
-                commit: commit,
+                commit,
                 subdirectory: Some("recipes".to_string()),
                 reference: GitReference::Branch("main".to_string()),
             },
@@ -496,7 +496,7 @@ mod tests {
         let build_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
             git: git_url.clone(),
             source: PinnedGitCheckout {
-                commit: commit,
+                commit,
                 subdirectory: Some("src".to_string()),
                 reference: GitReference::Branch("main".to_string()),
             },

From 7aa0e5c83cedaf16ca7019ac65d798468b25683d Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 12:09:30 +0100
Subject: [PATCH 13/21] fix: satisfiability

---
 crates/pixi_core/src/lock_file/satisfiability/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/pixi_core/src/lock_file/satisfiability/mod.rs b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
index 19da02d82b..8c25cf891a 100644
--- a/crates/pixi_core/src/lock_file/satisfiability/mod.rs
+++ b/crates/pixi_core/src/lock_file/satisfiability/mod.rs
@@ -1509,7 +1509,7 @@ pub(crate) async fn verify_package_platform_satisfiability(
             };
 
             // Resolve build_source relative to the manifest directory
-            build_path_record.resolve(&project_root)
+            build_path_record.resolve(project_root)
         } else {
             let Some(path_record) = source_record.manifest_source.as_path() else {
                 continue;

From a061514cf9f3d98cb838a7b9775c36e6c969fc48 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 15:15:14 +0100
Subject: [PATCH 14/21] fix: path normalization

---
 Cargo.lock                                    |   1 +
 crates/pixi_record/Cargo.toml                 |   1 +
 crates/pixi_record/src/pinned_source.rs       |  22 +-
 ...d__tests__roundtrip_conda_source_data.snap | 126 +++++++----
 crates/pixi_record/src/source_record.rs       | 195 +++++++++---------
 5 files changed, 201 insertions(+), 144 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index b66b6d2f10..866442e211 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5295,6 +5295,7 @@ dependencies = [
 name = "pixi_record"
 version = "0.1.0"
 dependencies = [
+ "dunce",
  "file_url",
  "insta",
  "miette 7.6.0",
diff --git a/crates/pixi_record/Cargo.toml b/crates/pixi_record/Cargo.toml
index 8e3c8c2a5a..351105a7e0 100644
--- a/crates/pixi_record/Cargo.toml
+++ b/crates/pixi_record/Cargo.toml
@@ -10,6 +10,7 @@ repository.workspace = true
 version = "0.1.0"
 
 [dependencies]
+dunce = { workspace = true }
 file_url = { workspace = true }
 miette = { workspace = true }
 pathdiff = { workspace = true }
diff --git a/crates/pixi_record/src/pinned_source.rs b/crates/pixi_record/src/pinned_source.rs
index eaf1b7e486..9f7f49bdf9 100644
--- a/crates/pixi_record/src/pinned_source.rs
+++ b/crates/pixi_record/src/pinned_source.rs
@@ -251,22 +251,20 @@ impl PinnedSourceSpec {
                     return None;
                 }
 
-                // bas = { git = "ssh@tim", subdir = "baz" }
-                //
-                // [package.build]
-                // source = foo/bar
-                //
-
-                // Same repository - compute relative path between subdirectories
-                //  baz
+                // Same repository and commit - compute relative path between subdirectories
+                // Both subdirectories are relative to the repository root
                 let base_subdir = base_git.source.subdirectory.as_deref().unwrap_or("");
-                // baz/foo/bar
                 let this_subdir = this_git.source.subdirectory.as_deref().unwrap_or("");
 
-                //foo/bar
-                let relative_path = pathdiff::diff_paths(this_subdir, base_subdir)?;
+                // Compute the relative path from base to this
+                let base_path = std::path::Path::new(base_subdir);
+                let this_path = std::path::Path::new(this_subdir);
+
+                let relative = pathdiff::diff_paths(this_path, base_path)?;
+                let relative_str = relative.to_str()?;
+
                 Some(PinnedSourceSpec::Path(PinnedPathSpec {
-                    path: Utf8TypedPathBuf::from(relative_path.to_string_lossy().as_ref()),
+                    path: Utf8TypedPathBuf::from(relative_str),
                 }))
             }
             (PinnedSourceSpec::Url(_), _) => unreachable!("url specs have not been implemented"),
diff --git a/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap b/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
index aff2185125..38ff3bf88c 100644
--- a/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
+++ b/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
@@ -1,39 +1,93 @@
 ---
 source: crates/pixi_record/src/source_record.rs
-expression: roundtrip
+expression: roundtrips
 ---
-package_record:
-  build: h123456_0
-  build_number: 0
-  depends: []
-  md5: d41d8cd98f00b204e9800998ecf8427e
-  name: comprehensive-test
-  sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
-  subdir: noarch
-  version: 1.0.0
-manifest_source:
-  commit: abc123def456abc123def456abc123def456abc1
-  git: "https://github.com/example/mono-repo.git"
-  reference:
-    branch: main
-  subdirectory: recipes
-build_source:
-  commit: abc123def456abc123def456abc123def456abc1
-  git: "https://github.com/example/mono-repo.git"
-  reference:
-    branch: main
-  subdirectory: recipes/nested/src
-input_hash:
-  hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
-  globs:
-    - "**/*.py"
-    - "**/*.txt"
-sources:
-  git-dep:
-    location:
-      git: "https://github.com/example/dep.git"
-      subdirectory: python
-      tag: v1.0.0
-  path-dep:
-    location:
-      path: "../vendor"
+- package_record:
+    build: h123456_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: git-sibling-test
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 1.0.0
+  manifest_source:
+    commit: abc123def456abc123def456abc123def456abc1
+    git: "https://github.com/example/mono-repo.git"
+    reference:
+      branch: main
+    subdirectory: recipes
+  build_source:
+    commit: abc123def456abc123def456abc123def456abc1
+    git: "https://github.com/example/mono-repo.git"
+    reference:
+      branch: main
+    subdirectory: nested/src
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.py"
+      - "**/*.txt"
+  sources: {}
+- package_record:
+    build: h234567_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: git-child-test
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 1.1.0
+  manifest_source:
+    commit: abc123def456abc123def456abc123def456abc1
+    git: "https://github.com/example/mono-repo.git"
+    reference:
+      branch: main
+    subdirectory: recipes
+  build_source:
+    commit: abc123def456abc123def456abc123def456abc1
+    git: "https://github.com/example/mono-repo.git"
+    reference:
+      branch: main
+    subdirectory: src
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.c"
+  sources: {}
+- package_record:
+    build: h789012_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: path-sibling-test
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 2.0.0
+  manifest_source:
+    path: recipes/my-package
+  build_source:
+    path: other-package/src
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.rs"
+  sources: {}
+- package_record:
+    build: h890123_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: path-child-test
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 2.1.0
+  manifest_source:
+    path: recipes/my-package
+  build_source:
+    path: src/lib
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.cpp"
+  sources: {}
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index b51b4e4c30..d45f0565e4 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -1,6 +1,7 @@
 use std::{
     collections::{BTreeSet, HashMap},
-    path::Path,
+    ffi::{OsStr, OsString},
+    path::{Path, PathBuf},
     str::FromStr,
 };
 
@@ -171,15 +172,23 @@ impl SourceRecord {
                     match &manifest_source {
                         PinnedSourceSpec::Url(_) => unimplemented!(),
                         PinnedSourceSpec::Git(pinned_git_spec) => {
-                            let base_dir = pinned_git_spec.source.subdirectory.as_ref();
-                            // Make `path` relative to repository root, if `base` is not None it will
-                            // be relative with `base` at this point, so lets join
-                            let subdir =
-                                base_dir.map(|base| Path::new(base).join(Path::new(path.as_str())));
+                            // The path is relative to the manifest subdirectory
+                            // Need to resolve it to get the absolute subdirectory in the repo
+                            let base_subdir =
+                                pinned_git_spec.source.subdirectory.as_deref().unwrap_or("");
+                            let base_path = std::path::Path::new(base_subdir);
+                            let relative_path = std::path::Path::new(path.as_str());
+
+                            // Join to get the subdirectory path and normalize away `.` / `..`
+                            let absolute_subdir = base_path.join(relative_path);
+                            let normalized = normalize_path(&absolute_subdir);
+                            let subdirectory = normalized
+                                .to_str()
+                                .expect("path should be valid UTF-8")
+                                .to_string();
 
                             let mut git_source = pinned_git_spec.source.clone();
-                            git_source.subdirectory =
-                                subdir.map(|p| p.to_string_lossy().to_string());
+                            git_source.subdirectory = Some(subdirectory);
 
                             // Reconstruct the git object
                             PinnedSourceSpec::Git(crate::PinnedGitSpec {
@@ -198,6 +207,7 @@ impl SourceRecord {
                             // Finally make the result relative to workspace_root
                             let manifest_absolute = manifest_path.resolve(workspace_root);
                             let build_absolute = build_source_spec.resolve(&manifest_absolute);
+                            let build_absolute = normalize_path(&build_absolute);
 
                             // Make the normalized path relative to workspace_root
                             let relative_to_workspace =
@@ -270,6 +280,60 @@ impl AsRef<PackageRecord> for SourceRecord {
     }
 }
 
+fn normalize_path(path: &Path) -> PathBuf {
+    use std::path::Component;
+
+    // `dunce::simplified` is purely lexical and strips UNC verbatim prefixes on Windows.
+    let simplified = dunce::simplified(path).to_path_buf();
+
+    let mut prefix: Option<OsString> = None;
+    let mut has_root = false;
+    let mut parts: Vec<OsString> = Vec::new();
+
+    for component in simplified.components() {
+        match component {
+            Component::Prefix(prefix_component) => {
+                prefix = Some(prefix_component.as_os_str().to_os_string());
+                parts.clear();
+            }
+            Component::RootDir => {
+                has_root = true;
+                parts.clear();
+            }
+            Component::CurDir => {}
+            Component::ParentDir => {
+                if let Some(last) = parts.last() {
+                    if last.as_os_str() == OsStr::new("..") {
+                        parts.push(OsString::from(".."));
+                    } else {
+                        parts.pop();
+                    }
+                } else if !has_root {
+                    parts.push(OsString::from(".."));
+                }
+            }
+            Component::Normal(part) => parts.push(part.to_os_string()),
+        }
+    }
+
+    let mut normalized = PathBuf::new();
+    if let Some(prefix) = prefix {
+        normalized.push(prefix);
+    }
+    if has_root {
+        normalized.push(std::path::MAIN_SEPARATOR.to_string());
+    }
+    for part in parts {
+        normalized.push(part);
+    }
+
+    if normalized.as_os_str().is_empty() {
+        simplified
+    } else {
+        normalized
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -278,75 +342,6 @@ mod tests {
     use std::str::FromStr;
     use url::Url;
 
-    #[test]
-    fn package_build_source_roundtrip_preserves_git_subdirectory() {
-        let package_record: PackageRecord = serde_json::from_value(json!({
-            "name": "example",
-            "version": "1.0.0",
-            "build": "0",
-            "build_number": 0,
-            "subdir": "noarch",
-        }))
-        .expect("valid package record");
-
-        let git_url = Url::parse("https://example.com/repo.git").unwrap();
-        let pinned_source = PinnedSourceSpec::Git(crate::PinnedGitSpec {
-            git: git_url.clone(),
-            source: PinnedGitCheckout {
-                commit: GitSha::from_str("0123456789abcdef0123456789abcdef01234567").unwrap(),
-                subdirectory: Some("nested/project".to_string()),
-                reference: GitReference::Branch("main".to_string()),
-            },
-        });
-
-        let record = SourceRecord {
-            package_record,
-            manifest_source: pinned_source.clone(),
-            build_source: Some(pinned_source.clone()),
-            input_hash: None,
-            sources: Default::default(),
-        };
-
-        let conda_source = record
-            .clone()
-            .into_conda_source_data(&std::path::PathBuf::from("/workspace"));
-
-        let package_build_source = conda_source
-            .package_build_source
-            .as_ref()
-            .expect("expected package build source");
-
-        let PackageBuildSource::Git {
-            url,
-            spec,
-            rev,
-            subdir,
-        } = package_build_source
-        else {
-            panic!("expected git package build source");
-        };
-
-        assert_eq!(url.path(), "/repo.git");
-        assert_eq!(url.host_str(), Some("example.com"));
-        assert_eq!(subdir.as_ref().map(|s| s.as_str()), Some("nested/project"));
-        assert!(matches!(spec, Some(GitShallowSpec::Branch(branch)) if branch == "main"));
-        assert_eq!(rev, "0123456789abcdef0123456789abcdef01234567");
-
-        let roundtrip = SourceRecord::from_conda_source_data(
-            conda_source,
-            &std::path::PathBuf::from("/workspace"),
-        )
-        .expect("roundtrip should succeed");
-        let Some(PinnedSourceSpec::Git(roundtrip_git)) = roundtrip.build_source else {
-            panic!("expected git pinned source");
-        };
-        assert_eq!(
-            roundtrip_git.source.subdirectory.as_deref(),
-            Some("nested/project")
-        );
-        assert_eq!(roundtrip_git.git, git_url);
-    }
-
     #[test]
     fn package_build_source_path_is_made_relative() {
         use typed_path::Utf8TypedPathBuf;
@@ -411,12 +406,8 @@ mod tests {
             panic!("expected path pinned source");
         };
 
-        // After roundtrip, the path should remain as it was in the lock file (relative)
-        assert_eq!(
-            roundtrip_path.path.as_str(),
-            "../src",
-            "build_source should remain as relative path from lock file"
-        );
+        // After roundtrip, the path should again be from the repository root
+        assert_eq!(roundtrip_path.path.as_str(), "src");
     }
 
     #[test]
@@ -469,7 +460,7 @@ mod tests {
     }
 
     #[test]
-    fn package_build_source_git_same_repo_is_made_relative() {
+    fn package_build_source_roundtrip_git_with_subdir() {
         let package_record: PackageRecord = serde_json::from_value(json!({
             "name": "example",
             "version": "1.0.0",
@@ -538,14 +529,21 @@ mod tests {
         )
         .expect("roundtrip should succeed");
 
-        let Some(PinnedSourceSpec::Path(roundtrip_path)) = roundtrip.build_source else {
+        let Some(PinnedSourceSpec::Git(roundtrip_path)) = roundtrip.build_source else {
             panic!(
                 "expected path pinned source after roundtrip (deserialized from relative path in lock file)"
             );
         };
 
-        // After roundtrip, it should remain as the relative path from the lock file
-        assert_eq!(roundtrip_path.path.as_str(), "../src");
+        // After roundtrip, the path will contain .. components (not normalized)
+        assert_eq!(
+            roundtrip_path
+                .source
+                .subdirectory
+                .expect("subdirectory should be set")
+                .as_str(),
+            "src"
+        );
     }
 
     #[test]
@@ -615,7 +613,7 @@ mod tests {
     fn roundtrip_conda_source_data() {
         let workspace_root = std::path::Path::new("/workspace");
 
-        // Load the SourceRecord from snapshot (skip YAML frontmatter)
+        // Load the SourceRecords from snapshot (skip YAML frontmatter)
         let snapshot_content = include_str!(
             "snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap"
         );
@@ -623,19 +621,24 @@ mod tests {
             .split("---")
             .nth(2)
             .expect("snapshot should have YAML content");
-        let original: SourceRecord =
+        let originals: Vec<SourceRecord> =
             serde_yaml::from_str(yaml_content).expect("failed to load snapshot");
 
-        // Roundtrip: SourceRecord -> CondaSourceData -> SourceRecord
-        let conda_data = original.clone().into_conda_source_data(workspace_root);
-        let roundtrip = SourceRecord::from_conda_source_data(conda_data, workspace_root)
-            .expect("from_conda_source_data should succeed");
-
-        // Snapshot the final result - should match the original
+        // Roundtrip each record: SourceRecord -> CondaSourceData -> SourceRecord
+        let roundtrips: Vec<SourceRecord> = originals
+            .into_iter()
+            .map(|original| {
+                let conda_data = original.clone().into_conda_source_data(workspace_root);
+                SourceRecord::from_conda_source_data(conda_data, workspace_root)
+                    .expect("from_conda_source_data should succeed")
+            })
+            .collect();
+
+        // Snapshot the final results - should match the originals
         let mut settings = insta::Settings::clone_current();
         settings.set_sort_maps(true);
         settings.bind(|| {
-            insta::assert_yaml_snapshot!(roundtrip);
+            insta::assert_yaml_snapshot!(roundtrips);
         });
     }
 }

From 397d3506e55b6b0415a036750828f90bf6194649 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 16:03:48 +0100
Subject: [PATCH 15/21] fix: more tests

---
 ...d__tests__roundtrip_conda_source_data.snap |  96 +++++++
 crates/pixi_record/src/source_record.rs       | 261 ++++++++++++++----
 2 files changed, 297 insertions(+), 60 deletions(-)

diff --git a/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap b/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
index 38ff3bf88c..268f504cd7 100644
--- a/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
+++ b/crates/pixi_record/src/snapshots/pixi_record__source_record__tests__roundtrip_conda_source_data.snap
@@ -91,3 +91,99 @@ expression: roundtrips
     globs:
       - "**/*.cpp"
   sources: {}
+- package_record:
+    build: h901234_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: path-absolute-build-outside
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 2.2.0
+  manifest_source:
+    path: recipes/external-package
+  build_source:
+    path: /opt/external/sources/pkg
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.pyx"
+  sources: {}
+- package_record:
+    build: h901235_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: path-root-manifest
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 2.3.0
+  manifest_source:
+    path: ""
+  build_source:
+    path: src/root-build
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - pyproject.toml
+  sources: {}
+- package_record:
+    build: h901236_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: path-absolute-manifest
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 2.4.0
+  manifest_source:
+    path: /workspace/absolute-recipe
+  build_source:
+    path: absolute-recipe/src
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.sh"
+  sources: {}
+- package_record:
+    build: h901237_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: git-no-manifest-subdir
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 3.0.0
+  manifest_source:
+    commit: abc123def456abc123def456abc123def456abc1
+    git: "https://github.com/example/repo.git"
+    reference:
+      tag: v1.0.0
+  build_source:
+    commit: abc123def456abc123def456abc123def456abc1
+    git: "https://github.com/example/repo.git"
+    reference:
+      tag: v1.0.0
+    subdirectory: build/subdir
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - src/**/*.rs
+  sources: {}
+- package_record:
+    build: h901238_0
+    build_number: 0
+    depends: []
+    md5: d41d8cd98f00b204e9800998ecf8427e
+    name: path-no-build-source
+    sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    subdir: noarch
+    version: 2.5.0
+  manifest_source:
+    path: recipes/no-build
+  build_source: ~
+  input_hash:
+    hash: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+    globs:
+      - "**/*.md"
+  sources: {}
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index d45f0565e4..58bd49a9c1 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -5,13 +5,14 @@ use std::{
     str::FromStr,
 };
 
-use pixi_git::sha::GitSha;
+use pixi_git::{sha::GitSha, url::RepositoryUrl};
 use pixi_spec::{GitReference, SourceSpec};
 use rattler_conda_types::{MatchSpec, Matches, NamelessMatchSpec, PackageRecord};
 use rattler_digest::{Sha256, Sha256Hash};
 use rattler_lock::{CondaSourceData, GitShallowSpec, PackageBuildSource};
 use serde::{Deserialize, Serialize};
 use typed_path::Utf8TypedPathBuf;
+use url::Url;
 
 use crate::{ParseLockFileError, PinnedGitCheckout, PinnedSourceSpec};
 
@@ -64,45 +65,62 @@ impl SourceRecord {
     /// However, when saving in the lock-file make these relative to the package manifest.
     /// This should be used when writing to the lock file.
     pub fn into_conda_source_data(self, workspace_root: &Path) -> CondaSourceData {
-        let package_build_source = self.build_source.map(|build_source| {
-            let pinned_source_spec = build_source
-                .make_relative_to(&self.manifest_source, workspace_root)
-                .unwrap_or(build_source);
-
-            match pinned_source_spec {
-                PinnedSourceSpec::Url(pinned_url_spec) => PackageBuildSource::Url {
-                    url: pinned_url_spec.url,
-                    sha256: pinned_url_spec.sha256,
-                    subdir: None,
-                },
-                PinnedSourceSpec::Git(pinned_git_spec) => {
-                    let subdirectory = pinned_git_spec
-                        .source
-                        .subdirectory
-                        .as_deref()
-                        .map(Utf8TypedPathBuf::from);
-
-                    let spec = match &pinned_git_spec.source.reference {
-                        GitReference::Branch(branch) => {
-                            Some(GitShallowSpec::Branch(branch.clone()))
+        let package_build_source =
+            self.build_source
+                .clone()
+                .map(|build_source| match build_source {
+                    PinnedSourceSpec::Git(git_spec) => {
+                        // When manifest and build refer to the same repo+commit we keep the
+                        // build source as git, but rewrite its subdirectory relative to the
+                        // manifest checkout as expected by the lock file format.
+                        let mut subdirectory = git_spec.source.subdirectory.clone();
+
+                        if let PinnedSourceSpec::Git(manifest_git) = &self.manifest_source {
+                            if same_git_checkout(&git_spec, manifest_git) {
+                                subdirectory = relative_repo_subdir(
+                                    manifest_git.source.subdirectory.as_deref().unwrap_or(""),
+                                    git_spec.source.subdirectory.as_deref().unwrap_or(""),
+                                );
+                            }
+                        }
+
+                        let subdirectory = subdirectory.as_deref().map(Utf8TypedPathBuf::from);
+                        let spec = to_git_shallow(&git_spec.source.reference);
+
+                        PackageBuildSource::Git {
+                            url: git_spec.git,
+                            spec,
+                            rev: git_spec.source.commit.to_string(),
+                            subdir: subdirectory,
                         }
-                        GitReference::Tag(tag) => Some(GitShallowSpec::Tag(tag.clone())),
-                        GitReference::Rev(_) => Some(GitShallowSpec::Rev),
-                        GitReference::DefaultBranch => None,
-                    };
-
-                    PackageBuildSource::Git {
-                        url: pinned_git_spec.git,
-                        spec,
-                        rev: pinned_git_spec.source.commit.to_string(),
-                        subdir: subdirectory,
                     }
-                }
-                PinnedSourceSpec::Path(pinned_path) => PackageBuildSource::Path {
-                    path: pinned_path.path,
-                },
-            }
-        });
+                    PinnedSourceSpec::Url(pinned_url_spec) => PackageBuildSource::Url {
+                        url: pinned_url_spec.url,
+                        sha256: pinned_url_spec.sha256,
+                        subdir: None,
+                    },
+                    PinnedSourceSpec::Path(pinned_path) => {
+                        let native_path = Path::new(pinned_path.path.as_str());
+                        let should_relativize = !(native_path.is_absolute()
+                            && !native_path.starts_with(workspace_root));
+
+                        let relativized = if should_relativize {
+                            PinnedSourceSpec::Path(pinned_path.clone())
+                                .make_relative_to(&self.manifest_source, workspace_root)
+                                .unwrap_or(PinnedSourceSpec::Path(pinned_path.clone()))
+                        } else {
+                            PinnedSourceSpec::Path(pinned_path.clone())
+                        };
+
+                        let PinnedSourceSpec::Path(result_path) = relativized else {
+                            unreachable!("path specs must remain paths");
+                        };
+
+                        PackageBuildSource::Path {
+                            path: result_path.path,
+                        }
+                    }
+                });
 
         CondaSourceData {
             package_record: self.package_record,
@@ -139,19 +157,27 @@ impl SourceRecord {
                 rev,
                 subdir,
             } => {
-                let reference = match spec {
-                    Some(GitShallowSpec::Branch(branch)) => GitReference::Branch(branch),
-                    Some(GitShallowSpec::Tag(tag)) => GitReference::Tag(tag),
-                    Some(GitShallowSpec::Rev) => GitReference::Rev(rev.clone()),
-                    None => GitReference::DefaultBranch,
-                };
-
-                // Out-of-tree git repository
+                let mut subdirectory = subdir.map(|s| s.to_string());
+
+                if let PinnedSourceSpec::Git(manifest_git) = &manifest_source {
+                    // For same-repo checkouts the lock stored the subdir relative to the manifest;
+                    // restore the absolute repo subdirectory so SourceRecord stays workspace-root
+                    // relative again.
+                    if same_git_checkout_url_commit(manifest_git, &url, &rev) {
+                        subdirectory = resolve_repo_subdir(
+                            manifest_git.source.subdirectory.as_deref().unwrap_or(""),
+                            subdirectory.as_deref(),
+                        );
+                    }
+                }
+
+                let reference = git_reference_from_shallow(spec, &rev);
+
                 PinnedSourceSpec::Git(crate::PinnedGitSpec {
                     git: url,
                     source: PinnedGitCheckout {
                         commit: GitSha::from_str(&rev).unwrap(),
-                        subdirectory: subdir.map(|s| s.to_string()),
+                        subdirectory,
                         reference,
                     },
                 })
@@ -280,6 +306,7 @@ impl AsRef<PackageRecord> for SourceRecord {
     }
 }
 
+/// Normalize a path lexically (no filesystem access) and remove redundant separators/`..`.
 fn normalize_path(path: &Path) -> PathBuf {
     use std::path::Component;
 
@@ -327,10 +354,95 @@ fn normalize_path(path: &Path) -> PathBuf {
         normalized.push(part);
     }
 
+    normalized
+}
+
+/// Returns true when both git specs target the same repository (ignoring URL noise)
+/// and are pinned to the identical commit.
+fn same_git_checkout(a: &crate::PinnedGitSpec, b: &crate::PinnedGitSpec) -> bool {
+    RepositoryUrl::new(&a.git) == RepositoryUrl::new(&b.git) && a.source.commit == b.source.commit
+}
+
+/// Same check as `same_git_checkout`, but used while parsing lock data where only
+/// the URL + rev string are available.
+fn same_git_checkout_url_commit(manifest_git: &crate::PinnedGitSpec, url: &Url, rev: &str) -> bool {
+    RepositoryUrl::new(&manifest_git.git) == RepositoryUrl::new(url)
+        && manifest_git.source.commit.to_string() == rev
+}
+
+/// Compute the repo-relative path from `base` (manifest subdir) to `target`
+/// (build subdir). Returns `None` if the directories are identical/root.
+fn relative_repo_subdir(base: &str, target: &str) -> Option<String> {
+    let base_abs = repo_absolute_path(base);
+    let target_abs = repo_absolute_path(target);
+    let relative =
+        pathdiff::diff_paths(&target_abs, &base_abs).unwrap_or_else(|| target_abs.clone());
+    let normalized = normalize_path(&relative);
     if normalized.as_os_str().is_empty() {
-        simplified
+        None
     } else {
-        normalized
+        Some(normalized.to_string_lossy().to_string())
+    }
+}
+
+/// Undo `relative_repo_subdir`: apply the manifest subdir back onto the relative
+/// path that was stored in the lock, so we get the real repo subdirectory again.
+fn resolve_repo_subdir(base: &str, relative: Option<&str>) -> Option<String> {
+    match relative {
+        Some(rel) => {
+            let combined = repo_absolute_path(base).join(rel);
+            strip_repo_root(normalize_path(&combined))
+        }
+        None => {
+            if base.is_empty() {
+                None
+            } else {
+                Some(base.to_string())
+            }
+        }
+    }
+}
+
+fn repo_absolute_path(subdir: &str) -> PathBuf {
+    if subdir.is_empty() {
+        PathBuf::from("/")
+    } else {
+        Path::new("/").join(subdir)
+    }
+}
+
+fn strip_repo_root(path: PathBuf) -> Option<String> {
+    let trimmed = if path.has_root() {
+        match path.strip_prefix(Path::new("/")) {
+            Ok(stripped) => stripped.to_path_buf(),
+            Err(_) => path,
+        }
+    } else {
+        path
+    };
+
+    if trimmed.as_os_str().is_empty() {
+        None
+    } else {
+        Some(trimmed.to_string_lossy().to_string())
+    }
+}
+
+fn to_git_shallow(reference: &GitReference) -> Option<GitShallowSpec> {
+    match reference {
+        GitReference::Branch(branch) => Some(GitShallowSpec::Branch(branch.clone())),
+        GitReference::Tag(tag) => Some(GitShallowSpec::Tag(tag.clone())),
+        GitReference::Rev(_) => Some(GitShallowSpec::Rev),
+        GitReference::DefaultBranch => None,
+    }
+}
+
+fn git_reference_from_shallow(spec: Option<GitShallowSpec>, rev: &str) -> GitReference {
+    match spec {
+        Some(GitShallowSpec::Branch(branch)) => GitReference::Branch(branch),
+        Some(GitShallowSpec::Tag(tag)) => GitReference::Tag(tag),
+        Some(GitShallowSpec::Rev) => GitReference::Rev(rev.to_string()),
+        None => GitReference::DefaultBranch,
     }
 }
 
@@ -339,7 +451,7 @@ mod tests {
     use super::*;
     use pixi_git::sha::GitSha;
     use serde_json::json;
-    use std::str::FromStr;
+    use std::{path::Path, str::FromStr};
     use url::Url;
 
     #[test]
@@ -455,8 +567,8 @@ mod tests {
             panic!("expected path package build source");
         };
 
-        // The path should be made relative
-        assert_eq!(path.as_str(), "../../completely/different/path");
+        // The path should stay absolute because the build source is unrelated
+        assert_eq!(path.as_str(), "/completely/different/path");
     }
 
     #[test]
@@ -511,16 +623,11 @@ mod tests {
             .as_ref()
             .expect("expected package build source");
 
-        let PackageBuildSource::Path { path } = package_build_source else {
-            panic!("expected path package build source (relativized from git)");
+        let PackageBuildSource::Git { subdir, .. } = package_build_source else {
+            panic!("expected git package build source with relative subdir");
         };
 
-        // The path should be relative: from recipes/ to src/ is ../src
-        assert_eq!(
-            path.as_str(),
-            "../src",
-            "build_source should be converted to relative path"
-        );
+        assert_eq!(subdir.as_ref().map(|s| s.as_str()), Some("../src"));
 
         // Convert back to SourceRecord (deserialization)
         let roundtrip = SourceRecord::from_conda_source_data(
@@ -641,4 +748,38 @@ mod tests {
             insta::assert_yaml_snapshot!(roundtrips);
         });
     }
+
+    #[test]
+    fn normalize_path_collapses_parent_segments() {
+        let normalized = super::normalize_path(Path::new("recipes/../"));
+        assert!(normalized.as_os_str().is_empty());
+    }
+
+    #[test]
+    fn repo_subdir_helpers_round_trip() {
+        use super::{relative_repo_subdir, resolve_repo_subdir};
+
+        let manifest = "recipes";
+        let build = "recipes/lib";
+
+        let relative = relative_repo_subdir(manifest, build).expect("should produce relative path");
+        assert_eq!(relative, "lib");
+
+        let resolved = resolve_repo_subdir(manifest, Some(relative.as_str()));
+        assert_eq!(resolved.as_deref(), Some("recipes/lib"));
+    }
+
+    #[test]
+    fn repo_subdir_helpers_handle_root() {
+        use super::{relative_repo_subdir, resolve_repo_subdir};
+
+        // Both manifest and build at repo root
+        assert!(relative_repo_subdir("", "").is_none());
+        assert!(resolve_repo_subdir("", None).is_none());
+
+        // Manifest at root, build in subdir
+        let rel = relative_repo_subdir("", "src").expect("relative path");
+        assert_eq!(rel, "src");
+        assert_eq!(resolve_repo_subdir("", Some("src")).as_deref(), Some("src"));
+    }
 }

From 7df20ae1f73bf5c22b129ebf87efd7c0310b722b Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 16:06:50 +0100
Subject: [PATCH 16/21] fix: clippy

---
 crates/pixi_record/src/source_record.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index 58bd49a9c1..0fafca7b2d 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -101,8 +101,8 @@ impl SourceRecord {
                     },
                     PinnedSourceSpec::Path(pinned_path) => {
                         let native_path = Path::new(pinned_path.path.as_str());
-                        let should_relativize = !(native_path.is_absolute()
-                            && !native_path.starts_with(workspace_root));
+                        let should_relativize =
+                            !native_path.is_absolute() || native_path.starts_with(workspace_root);
 
                         let relativized = if should_relativize {
                             PinnedSourceSpec::Path(pinned_path.clone())

From b517bc377b8ae5f7f51ce639ea7e82fafe24f724 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 17:43:15 +0100
Subject: [PATCH 17/21] feat: pull out path dependencies

---
 crates/pixi_record/src/lib.rs           |   1 +
 crates/pixi_record/src/path_utils.rs    | 196 +++++++++++++++++++++
 crates/pixi_record/src/source_record.rs | 217 +++++++-----------------
 3 files changed, 261 insertions(+), 153 deletions(-)
 create mode 100644 crates/pixi_record/src/path_utils.rs

diff --git a/crates/pixi_record/src/lib.rs b/crates/pixi_record/src/lib.rs
index cf65141fd3..63f6fec85b 100644
--- a/crates/pixi_record/src/lib.rs
+++ b/crates/pixi_record/src/lib.rs
@@ -1,3 +1,4 @@
+mod path_utils;
 mod pinned_source;
 mod source_record;
 
diff --git a/crates/pixi_record/src/path_utils.rs b/crates/pixi_record/src/path_utils.rs
new file mode 100644
index 0000000000..77033b013e
--- /dev/null
+++ b/crates/pixi_record/src/path_utils.rs
@@ -0,0 +1,196 @@
+use std::path::{Path, PathBuf};
+
+/// Normalize a path lexically (no filesystem access) and strip redundant segments.
+pub(crate) fn normalize_path(path: &Path) -> PathBuf {
+    use std::path::Component;
+
+    let simplified = dunce::simplified(path).to_path_buf();
+
+    let mut prefix: Option<std::ffi::OsString> = None;
+    let mut has_root = false;
+    let mut parts: Vec<std::ffi::OsString> = Vec::new();
+
+    for component in simplified.components() {
+        match component {
+            Component::Prefix(prefix_component) => {
+                prefix = Some(prefix_component.as_os_str().to_os_string());
+                parts.clear();
+            }
+            Component::RootDir => {
+                has_root = true;
+                parts.clear();
+            }
+            Component::CurDir => {}
+            Component::ParentDir => {
+                if let Some(last) = parts.last() {
+                    if last.as_os_str() == std::ffi::OsStr::new("..") {
+                        parts.push(std::ffi::OsString::from(".."));
+                    } else {
+                        parts.pop();
+                    }
+                } else if !has_root {
+                    parts.push(std::ffi::OsString::from(".."));
+                }
+            }
+            Component::Normal(part) => parts.push(part.to_os_string()),
+        }
+    }
+
+    let mut normalized = PathBuf::new();
+    if let Some(prefix) = prefix {
+        normalized.push(prefix);
+    }
+    if has_root {
+        normalized.push(std::path::MAIN_SEPARATOR.to_string());
+    }
+    for part in parts {
+        normalized.push(part);
+    }
+
+    normalized
+}
+
+/// Compute the repo-relative path from `base` (manifest subdir) to `target` (build subdir).
+pub(crate) fn relative_repo_subdir(base: &str, target: &str) -> Option<String> {
+    let base_abs = repo_absolute_path(base);
+    let target_abs = repo_absolute_path(target);
+    let relative =
+        pathdiff::diff_paths(&target_abs, &base_abs).unwrap_or_else(|| target_abs.clone());
+    let normalized = normalize_path(&relative);
+    if normalized.as_os_str().is_empty() {
+        None
+    } else {
+        Some(unixify_path(&normalized))
+    }
+}
+
+/// Apply a manifest subdir back onto a relative path stored in the lock.
+pub(crate) fn resolve_repo_subdir(base: &str, relative: Option<&str>) -> Option<String> {
+    match relative {
+        Some(rel) => {
+            let combined = repo_absolute_path(base).join(rel);
+            strip_repo_root(normalize_path(&combined))
+        }
+        None => {
+            if base.is_empty() {
+                None
+            } else {
+                Some(unixify_str(base))
+            }
+        }
+    }
+}
+
+fn repo_absolute_path(subdir: &str) -> PathBuf {
+    if subdir.is_empty() {
+        PathBuf::from("/")
+    } else {
+        Path::new("/").join(subdir)
+    }
+}
+
+fn strip_repo_root(path: PathBuf) -> Option<String> {
+    let trimmed = if path.has_root() {
+        match path.strip_prefix(Path::new("/")) {
+            Ok(stripped) => stripped.to_path_buf(),
+            Err(_) => path,
+        }
+    } else {
+        path
+    };
+
+    if trimmed.as_os_str().is_empty() {
+        None
+    } else {
+        Some(unixify_path(&trimmed))
+    }
+}
+
+pub(crate) fn unixify_path(path: &Path) -> String {
+    path.to_string_lossy().replace('\\', "/")
+}
+
+pub(crate) fn unixify_str(value: &str) -> String {
+    value.replace('\\', "/")
+}
+
+/// Returns true if the string should be treated as absolute regardless of host OS.
+pub(crate) fn is_cross_platform_absolute(path_str: &str, native_path: &Path) -> bool {
+    if native_path.is_absolute() {
+        return true;
+    }
+
+    if path_str.starts_with('/') || path_str.starts_with('\\') {
+        return true;
+    }
+
+    if path_str.len() >= 3 {
+        let bytes = path_str.as_bytes();
+        let drive = bytes[0];
+        let colon = bytes[1];
+        let slash = bytes[2];
+
+        if drive.is_ascii_alphabetic() && colon == b':' && (slash == b'/' || slash == b'\\') {
+            return true;
+        }
+    }
+
+    false
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn normalize_path_collapses_parent_segments() {
+        let normalized = normalize_path(Path::new("recipes/../"));
+        assert!(normalized.as_os_str().is_empty());
+    }
+
+    #[test]
+    fn repo_subdir_helpers_round_trip() {
+        let manifest = "recipes";
+        let build = "recipes/lib";
+
+        let relative = relative_repo_subdir(manifest, build).expect("should produce relative path");
+        assert_eq!(relative, "lib");
+
+        let resolved = resolve_repo_subdir(manifest, Some(relative.as_str()));
+        assert_eq!(resolved.as_deref(), Some("recipes/lib"));
+    }
+
+    #[test]
+    fn repo_subdir_helpers_handle_root() {
+        assert!(relative_repo_subdir("", "").is_none());
+        assert!(resolve_repo_subdir("", None).is_none());
+
+        let rel = relative_repo_subdir("", "src").expect("relative path");
+        assert_eq!(rel, "src");
+        assert_eq!(resolve_repo_subdir("", Some("src")).as_deref(), Some("src"));
+    }
+
+    #[test]
+    fn cross_platform_absolute_detection() {
+        assert!(is_cross_platform_absolute(
+            "/opt/external",
+            Path::new("/opt/external")
+        ));
+        assert!(is_cross_platform_absolute(
+            r"C:\work",
+            Path::new(r"C:\work")
+        ));
+        assert!(is_cross_platform_absolute(
+            r"\\server\share",
+            Path::new(r"\\server\share")
+        ));
+        assert!(is_cross_platform_absolute(
+            "/just/slash",
+            Path::new("just\\slash")
+        ));
+        assert!(!is_cross_platform_absolute(
+            "relative/path",
+            Path::new("relative/path")
+        ));
+    }
+}
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index 0fafca7b2d..2e3c3b7357 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -1,7 +1,6 @@
 use std::{
     collections::{BTreeSet, HashMap},
-    ffi::{OsStr, OsString},
-    path::{Path, PathBuf},
+    path::Path,
     str::FromStr,
 };
 
@@ -14,7 +13,13 @@ use serde::{Deserialize, Serialize};
 use typed_path::Utf8TypedPathBuf;
 use url::Url;
 
-use crate::{ParseLockFileError, PinnedGitCheckout, PinnedSourceSpec};
+use crate::{
+    ParseLockFileError, PinnedGitCheckout, PinnedSourceSpec,
+    path_utils::{
+        is_cross_platform_absolute, normalize_path, relative_repo_subdir, resolve_repo_subdir,
+        unixify_path,
+    },
+};
 
 /// A record of a conda package that still requires building.
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
@@ -100,9 +105,14 @@ impl SourceRecord {
                         subdir: None,
                     },
                     PinnedSourceSpec::Path(pinned_path) => {
-                        let native_path = Path::new(pinned_path.path.as_str());
-                        let should_relativize =
-                            !native_path.is_absolute() || native_path.starts_with(workspace_root);
+                        let path_str = pinned_path.path.as_str();
+                        let native_path = Path::new(path_str);
+                        let is_native_absolute = native_path.is_absolute();
+                        let is_cross_platform_absolute =
+                            is_cross_platform_absolute(path_str, native_path);
+                        let is_within_workspace =
+                            is_native_absolute && native_path.starts_with(workspace_root);
+                        let should_relativize = !is_cross_platform_absolute || is_within_workspace;
 
                         let relativized = if should_relativize {
                             PinnedSourceSpec::Path(pinned_path.clone())
@@ -241,9 +251,7 @@ impl SourceRecord {
                                     .unwrap_or(build_absolute);
 
                             PinnedSourceSpec::Path(crate::PinnedPathSpec {
-                                path: Utf8TypedPathBuf::from(
-                                    relative_to_workspace.to_string_lossy().as_ref(),
-                                ),
+                                path: Utf8TypedPathBuf::from(unixify_path(&relative_to_workspace)),
                             })
                         }
                     }
@@ -307,56 +315,6 @@ impl AsRef<PackageRecord> for SourceRecord {
 }
 
 /// Normalize a path lexically (no filesystem access) and remove redundant separators/`..`.
-fn normalize_path(path: &Path) -> PathBuf {
-    use std::path::Component;
-
-    // `dunce::simplified` is purely lexical and strips UNC verbatim prefixes on Windows.
-    let simplified = dunce::simplified(path).to_path_buf();
-
-    let mut prefix: Option<OsString> = None;
-    let mut has_root = false;
-    let mut parts: Vec<OsString> = Vec::new();
-
-    for component in simplified.components() {
-        match component {
-            Component::Prefix(prefix_component) => {
-                prefix = Some(prefix_component.as_os_str().to_os_string());
-                parts.clear();
-            }
-            Component::RootDir => {
-                has_root = true;
-                parts.clear();
-            }
-            Component::CurDir => {}
-            Component::ParentDir => {
-                if let Some(last) = parts.last() {
-                    if last.as_os_str() == OsStr::new("..") {
-                        parts.push(OsString::from(".."));
-                    } else {
-                        parts.pop();
-                    }
-                } else if !has_root {
-                    parts.push(OsString::from(".."));
-                }
-            }
-            Component::Normal(part) => parts.push(part.to_os_string()),
-        }
-    }
-
-    let mut normalized = PathBuf::new();
-    if let Some(prefix) = prefix {
-        normalized.push(prefix);
-    }
-    if has_root {
-        normalized.push(std::path::MAIN_SEPARATOR.to_string());
-    }
-    for part in parts {
-        normalized.push(part);
-    }
-
-    normalized
-}
-
 /// Returns true when both git specs target the same repository (ignoring URL noise)
 /// and are pinned to the identical commit.
 fn same_git_checkout(a: &crate::PinnedGitSpec, b: &crate::PinnedGitSpec) -> bool {
@@ -370,64 +328,6 @@ fn same_git_checkout_url_commit(manifest_git: &crate::PinnedGitSpec, url: &Url,
         && manifest_git.source.commit.to_string() == rev
 }
 
-/// Compute the repo-relative path from `base` (manifest subdir) to `target`
-/// (build subdir). Returns `None` if the directories are identical/root.
-fn relative_repo_subdir(base: &str, target: &str) -> Option<String> {
-    let base_abs = repo_absolute_path(base);
-    let target_abs = repo_absolute_path(target);
-    let relative =
-        pathdiff::diff_paths(&target_abs, &base_abs).unwrap_or_else(|| target_abs.clone());
-    let normalized = normalize_path(&relative);
-    if normalized.as_os_str().is_empty() {
-        None
-    } else {
-        Some(normalized.to_string_lossy().to_string())
-    }
-}
-
-/// Undo `relative_repo_subdir`: apply the manifest subdir back onto the relative
-/// path that was stored in the lock, so we get the real repo subdirectory again.
-fn resolve_repo_subdir(base: &str, relative: Option<&str>) -> Option<String> {
-    match relative {
-        Some(rel) => {
-            let combined = repo_absolute_path(base).join(rel);
-            strip_repo_root(normalize_path(&combined))
-        }
-        None => {
-            if base.is_empty() {
-                None
-            } else {
-                Some(base.to_string())
-            }
-        }
-    }
-}
-
-fn repo_absolute_path(subdir: &str) -> PathBuf {
-    if subdir.is_empty() {
-        PathBuf::from("/")
-    } else {
-        Path::new("/").join(subdir)
-    }
-}
-
-fn strip_repo_root(path: PathBuf) -> Option<String> {
-    let trimmed = if path.has_root() {
-        match path.strip_prefix(Path::new("/")) {
-            Ok(stripped) => stripped.to_path_buf(),
-            Err(_) => path,
-        }
-    } else {
-        path
-    };
-
-    if trimmed.as_os_str().is_empty() {
-        None
-    } else {
-        Some(trimmed.to_string_lossy().to_string())
-    }
-}
-
 fn to_git_shallow(reference: &GitReference) -> Option<GitShallowSpec> {
     match reference {
         GitReference::Branch(branch) => Some(GitShallowSpec::Branch(branch.clone())),
@@ -451,7 +351,7 @@ mod tests {
     use super::*;
     use pixi_git::sha::GitSha;
     use serde_json::json;
-    use std::{path::Path, str::FromStr};
+    use std::str::FromStr;
     use url::Url;
 
     #[test]
@@ -499,15 +399,15 @@ mod tests {
             panic!("expected path package build source");
         };
 
-        // The path should now be relative to the manifest directory
-        // Manifest is in /workspace/recipes/, so ../src should point to /workspace/src
+        // Because manifest + build live in the same git repo we serialize the build as a git
+        // source with a subdir relative to the manifest checkout.
         assert_eq!(
             path.as_str(),
             "../src",
             "build_source should be relative to manifest_source directory"
         );
 
-        // Convert back to SourceRecord (deserialization)
+        // Convert back to SourceRecord (deserialization) and ensure we recover repo-root subdir
         let roundtrip = SourceRecord::from_conda_source_data(
             conda_source,
             &std::path::PathBuf::from("/workspace"),
@@ -518,7 +418,7 @@ mod tests {
             panic!("expected path pinned source");
         };
 
-        // After roundtrip, the path should again be from the repository root
+        // After roundtrip the git subdirectory should be expressed from repo root again.
         assert_eq!(roundtrip_path.path.as_str(), "src");
     }
 
@@ -627,6 +527,7 @@ mod tests {
             panic!("expected git package build source with relative subdir");
         };
 
+        // Git subdir is relative to manifest checkout (recipes -> ../src)
         assert_eq!(subdir.as_ref().map(|s| s.as_str()), Some("../src"));
 
         // Convert back to SourceRecord (deserialization)
@@ -750,36 +651,46 @@ mod tests {
     }
 
     #[test]
-    fn normalize_path_collapses_parent_segments() {
-        let normalized = super::normalize_path(Path::new("recipes/../"));
-        assert!(normalized.as_os_str().is_empty());
-    }
-
-    #[test]
-    fn repo_subdir_helpers_round_trip() {
-        use super::{relative_repo_subdir, resolve_repo_subdir};
-
-        let manifest = "recipes";
-        let build = "recipes/lib";
-
-        let relative = relative_repo_subdir(manifest, build).expect("should produce relative path");
-        assert_eq!(relative, "lib");
-
-        let resolved = resolve_repo_subdir(manifest, Some(relative.as_str()));
-        assert_eq!(resolved.as_deref(), Some("recipes/lib"));
-    }
-
-    #[test]
-    fn repo_subdir_helpers_handle_root() {
-        use super::{relative_repo_subdir, resolve_repo_subdir};
-
-        // Both manifest and build at repo root
-        assert!(relative_repo_subdir("", "").is_none());
-        assert!(resolve_repo_subdir("", None).is_none());
-
-        // Manifest at root, build in subdir
-        let rel = relative_repo_subdir("", "src").expect("relative path");
-        assert_eq!(rel, "src");
-        assert_eq!(resolve_repo_subdir("", Some("src")).as_deref(), Some("src"));
+    fn git_reference_conversion_helpers() {
+        use super::{git_reference_from_shallow, to_git_shallow};
+        use pixi_spec::GitReference;
+        use rattler_lock::GitShallowSpec;
+
+        assert!(matches!(
+            to_git_shallow(&GitReference::Branch("main".into())),
+            Some(GitShallowSpec::Branch(branch)) if branch == "main"
+        ));
+
+        assert!(matches!(
+            to_git_shallow(&GitReference::Tag("v1".into())),
+            Some(GitShallowSpec::Tag(tag)) if tag == "v1"
+        ));
+
+        assert!(matches!(
+            to_git_shallow(&GitReference::Rev("abc".into())),
+            Some(GitShallowSpec::Rev)
+        ));
+
+        assert!(matches!(to_git_shallow(&GitReference::DefaultBranch), None));
+
+        assert!(matches!(
+            git_reference_from_shallow(Some(GitShallowSpec::Branch("dev".into())), "ignored"),
+            GitReference::Branch(branch) if branch == "dev"
+        ));
+
+        assert!(matches!(
+            git_reference_from_shallow(Some(GitShallowSpec::Tag("v2".into())), "ignored"),
+            GitReference::Tag(tag) if tag == "v2"
+        ));
+
+        assert!(matches!(
+            git_reference_from_shallow(Some(GitShallowSpec::Rev), "deadbeef"),
+            GitReference::Rev(rev) if rev == "deadbeef"
+        ));
+
+        assert!(matches!(
+            git_reference_from_shallow(None, "deadbeef"),
+            GitReference::DefaultBranch
+        ));
     }
 }

From 1d76082116c2b696ba6b11929618951e7c404091 Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 17:46:38 +0100
Subject: [PATCH 18/21] fix: clippy

---
 crates/pixi_record/src/source_record.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index 2e3c3b7357..eb11e734ce 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -671,7 +671,7 @@ mod tests {
             Some(GitShallowSpec::Rev)
         ));
 
-        assert!(matches!(to_git_shallow(&GitReference::DefaultBranch), None));
+        assert!(to_git_shallow(&GitReference::DefaultBranch).is_none());
 
         assert!(matches!(
             git_reference_from_shallow(Some(GitShallowSpec::Branch("dev".into())), "ignored"),

From a84faf08a827c663b9b8dfe67740aef880341c4f Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Fri, 7 Nov 2025 18:04:03 +0100
Subject: [PATCH 19/21] fix: fix windows path handling again

---
 crates/pixi_record/src/pinned_source.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crates/pixi_record/src/pinned_source.rs b/crates/pixi_record/src/pinned_source.rs
index 83055f9e1c..d83fb8f9b9 100644
--- a/crates/pixi_record/src/pinned_source.rs
+++ b/crates/pixi_record/src/pinned_source.rs
@@ -5,6 +5,7 @@ use std::{
     str::FromStr,
 };
 
+use crate::path_utils::unixify_path;
 use miette::IntoDiagnostic;
 use pixi_git::{
     GitUrl,
@@ -233,7 +234,7 @@ impl PinnedSourceSpec {
                 let relative_path = pathdiff::diff_paths(this_path, base_path)?;
 
                 Some(PinnedSourceSpec::Path(PinnedPathSpec {
-                    path: Utf8TypedPathBuf::from(relative_path.to_string_lossy().as_ref()),
+                    path: Utf8TypedPathBuf::from(unixify_path(relative_path.as_path())),
                 }))
             }
             // Git-to-Git: If same repository, convert to a relative path based on subdirectories
@@ -261,7 +262,7 @@ impl PinnedSourceSpec {
                 let this_path = std::path::Path::new(this_subdir);
 
                 let relative = pathdiff::diff_paths(this_path, base_path)?;
-                let relative_str = relative.to_str()?;
+                let relative_str = unixify_path(relative.as_path());
 
                 Some(PinnedSourceSpec::Path(PinnedPathSpec {
                     path: Utf8TypedPathBuf::from(relative_str),

From f91017d3b8020c8386392f5cee036dff5aca5e8c Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Sat, 8 Nov 2025 08:26:55 +0100
Subject: [PATCH 20/21] fix: codex attempts to fix path handling once again

---
 crates/pixi_record/src/path_utils.rs    | 49 +++++++++++++++++++++++++
 crates/pixi_record/src/source_record.rs |  7 ++--
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/crates/pixi_record/src/path_utils.rs b/crates/pixi_record/src/path_utils.rs
index 77033b013e..a3dd70e693 100644
--- a/crates/pixi_record/src/path_utils.rs
+++ b/crates/pixi_record/src/path_utils.rs
@@ -114,6 +114,34 @@ pub(crate) fn unixify_str(value: &str) -> String {
     value.replace('\\', "/")
 }
 
+pub(crate) fn path_within_workspace(
+    path_str: &str,
+    native_path: &Path,
+    workspace_root: &Path,
+) -> bool {
+    if native_path.is_absolute() {
+        return native_path.starts_with(workspace_root);
+    }
+
+    let path_unix = unixify_str(path_str);
+    let mut workspace_unix = unixify_path(workspace_root);
+    if workspace_unix.ends_with('/') {
+        workspace_unix.pop();
+    }
+
+    if workspace_unix.is_empty() {
+        return path_unix.starts_with('/');
+    }
+
+    if path_unix == workspace_unix {
+        return true;
+    }
+
+    path_unix.len() > workspace_unix.len()
+        && path_unix.starts_with(&workspace_unix)
+        && path_unix.as_bytes()[workspace_unix.len()] == b'/'
+}
+
 /// Returns true if the string should be treated as absolute regardless of host OS.
 pub(crate) fn is_cross_platform_absolute(path_str: &str, native_path: &Path) -> bool {
     if native_path.is_absolute() {
@@ -193,4 +221,25 @@ mod tests {
             Path::new("relative/path")
         ));
     }
+
+    #[test]
+    fn path_within_workspace_detection() {
+        assert!(path_within_workspace(
+            "/workspace/src",
+            Path::new("/workspace/src"),
+            Path::new("/workspace")
+        ));
+
+        assert!(path_within_workspace(
+            "/workspace/src",
+            Path::new("workspace\\src"),
+            Path::new("/workspace")
+        ));
+
+        assert!(!path_within_workspace(
+            "/other/src",
+            Path::new("/other/src"),
+            Path::new("/workspace")
+        ));
+    }
 }
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index eb11e734ce..687ac731be 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -16,8 +16,8 @@ use url::Url;
 use crate::{
     ParseLockFileError, PinnedGitCheckout, PinnedSourceSpec,
     path_utils::{
-        is_cross_platform_absolute, normalize_path, relative_repo_subdir, resolve_repo_subdir,
-        unixify_path,
+        is_cross_platform_absolute, normalize_path, path_within_workspace, relative_repo_subdir,
+        resolve_repo_subdir, unixify_path,
     },
 };
 
@@ -107,11 +107,10 @@ impl SourceRecord {
                     PinnedSourceSpec::Path(pinned_path) => {
                         let path_str = pinned_path.path.as_str();
                         let native_path = Path::new(path_str);
-                        let is_native_absolute = native_path.is_absolute();
                         let is_cross_platform_absolute =
                             is_cross_platform_absolute(path_str, native_path);
                         let is_within_workspace =
-                            is_native_absolute && native_path.starts_with(workspace_root);
+                            path_within_workspace(path_str, native_path, workspace_root);
                         let should_relativize = !is_cross_platform_absolute || is_within_workspace;
 
                         let relativized = if should_relativize {

From 0910693eb7573c6ea88b636f9fc68cb848854d8f Mon Sep 17 00:00:00 2001
From: Tim de Jager <tdejager89@gmail.com>
Date: Sat, 8 Nov 2025 11:35:52 +0100
Subject: [PATCH 21/21] feat: added some doc comments

---
 crates/pixi_record/src/path_utils.rs    | 5 +++--
 crates/pixi_record/src/pinned_source.rs | 2 ++
 crates/pixi_record/src/source_record.rs | 1 +
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/crates/pixi_record/src/path_utils.rs b/crates/pixi_record/src/path_utils.rs
index a3dd70e693..a82a5d40da 100644
--- a/crates/pixi_record/src/path_utils.rs
+++ b/crates/pixi_record/src/path_utils.rs
@@ -50,7 +50,8 @@ pub(crate) fn normalize_path(path: &Path) -> PathBuf {
     normalized
 }
 
-/// Compute the repo-relative path from `base` (manifest subdir) to `target` (build subdir).
+/// Compute the repo-relative path from `base` (manifest subdir) to `target` (build subdir), always
+/// returning `/`-separated strings so the lock format is stable across platforms.
 pub(crate) fn relative_repo_subdir(base: &str, target: &str) -> Option<String> {
     let base_abs = repo_absolute_path(base);
     let target_abs = repo_absolute_path(target);
@@ -64,7 +65,7 @@ pub(crate) fn relative_repo_subdir(base: &str, target: &str) -> Option<String> {
     }
 }
 
-/// Apply a manifest subdir back onto a relative path stored in the lock.
+/// Apply a manifest subdir back onto a relative path stored in the lock, again emitting `/`.
 pub(crate) fn resolve_repo_subdir(base: &str, relative: Option<&str>) -> Option<String> {
     match relative {
         Some(rel) => {
diff --git a/crates/pixi_record/src/pinned_source.rs b/crates/pixi_record/src/pinned_source.rs
index d83fb8f9b9..a88f0899a5 100644
--- a/crates/pixi_record/src/pinned_source.rs
+++ b/crates/pixi_record/src/pinned_source.rs
@@ -234,6 +234,7 @@ impl PinnedSourceSpec {
                 let relative_path = pathdiff::diff_paths(this_path, base_path)?;
 
                 Some(PinnedSourceSpec::Path(PinnedPathSpec {
+                    // `pathdiff` yields native separators; convert to `/` for lock-file stability.
                     path: Utf8TypedPathBuf::from(unixify_path(relative_path.as_path())),
                 }))
             }
@@ -262,6 +263,7 @@ impl PinnedSourceSpec {
                 let this_path = std::path::Path::new(this_subdir);
 
                 let relative = pathdiff::diff_paths(this_path, base_path)?;
+                // Same here: ensure lock only contains `/` even when diff runs on Windows paths.
                 let relative_str = unixify_path(relative.as_path());
 
                 Some(PinnedSourceSpec::Path(PinnedPathSpec {
diff --git a/crates/pixi_record/src/source_record.rs b/crates/pixi_record/src/source_record.rs
index 687ac731be..cae64214d0 100644
--- a/crates/pixi_record/src/source_record.rs
+++ b/crates/pixi_record/src/source_record.rs
@@ -250,6 +250,7 @@ impl SourceRecord {
                                     .unwrap_or(build_absolute);
 
                             PinnedSourceSpec::Path(crate::PinnedPathSpec {
+                                // Lock format is always `/`-separated even if diff runs on Windows.
                                 path: Utf8TypedPathBuf::from(unixify_path(&relative_to_workspace)),
                             })
                         }