add feature to disable src transform

Author: TroyKomodo

rust/private/rust.bzl

@@ -344,7 +344,7 @@ def _rust_test_impl(ctx):
         # Need to consider all src files together when transforming
         srcs = depset(ctx.files.srcs, transitive = [crate.srcs]).to_list()
         compile_data = depset(ctx.files.compile_data, transitive = [crate.compile_data]).to_list()
-        srcs, compile_data, crate_root = transform_sources(ctx, srcs, compile_data, getattr(ctx.file, "crate_root", None))
+        srcs, compile_data, crate_root = transform_sources(ctx, srcs, compile_data, crate.root)
 
         if crate.compile_data_targets:
             compile_data_targets = depset(ctx.attr.compile_data, transitive = [crate.compile_data_targets])
@@ -368,7 +368,7 @@ def _rust_test_impl(ctx):
         crate_info_dict = dict(
             name = crate_name,
             type = crate_type,
-            root = crate.root,
+            root = crate_root,
             srcs = depset(srcs),
             deps = depset(deps, transitive = [crate.deps]),
             proc_macro_deps = depset(proc_macro_deps, transitive = [crate.proc_macro_deps]),

rust/private/utils.bzl

@@ -828,13 +828,15 @@ def transform_sources(ctx, srcs, compile_data, crate_root):
         Tuple(List[File], List[File], File): The transformed srcs, compile_data
                                              and crate_root
     """
+    toolchain = find_toolchain(ctx)
+
     has_generated_sources = (
         len([src for src in srcs if not src.is_source]) +
         len([src for src in compile_data if not src.is_source]) >
         0
     )
 
-    if not has_generated_sources:
+    if not has_generated_sources or toolchain._incompatible_do_not_transform_sources:
         return srcs, compile_data, crate_root
 
     package_root = paths.join(ctx.label.workspace_root, ctx.label.package)

rust/settings/BUILD.bazel

@@ -24,6 +24,7 @@ load(
     "incompatible_change_clippy_error_format",
     "incompatible_change_rust_test_compilation_output_directory",
     "incompatible_do_not_include_data_in_compile_data",
+    "incompatible_do_not_transform_sources",
     "lto",
     "no_std",
     "pipelined_compilation",
@@ -102,6 +103,8 @@ incompatible_change_rust_test_compilation_output_directory()
 
 incompatible_do_not_include_data_in_compile_data()
 
+incompatible_do_not_transform_sources()
+
 lto()
 
 no_std()

rust/settings/settings.bzl

@@ -450,6 +450,16 @@ def incompatible_do_not_include_data_in_compile_data():
         issue = "https://github.com/bazelbuild/rules_rust/issues/2977",
     )
 
+# buildifier: disable=unnamed-macro
+def incompatible_do_not_transform_sources():
+    """A flag to control whether to include data files in compile_data.
+    """
+    incompatible_flag(
+        name = "incompatible_do_not_transform_sources",
+        build_setting_default = False,
+        issue = "https://github.com/bazelbuild/rules_rust/issues/<none>",
+    )
+
 def codegen_units():
     """The default value for `--codegen-units` which also affects resource allocation for rustc actions.
 

rust/toolchain.bzl

@@ -749,6 +749,7 @@ def _rust_toolchain_impl(ctx):
         _incompatible_change_rust_test_compilation_output_directory = ctx.attr._incompatible_change_rust_test_compilation_output_directory[IncompatibleFlagInfo].enabled,
         _toolchain_generated_sysroot = ctx.attr._toolchain_generated_sysroot[BuildSettingInfo].value,
         _incompatible_do_not_include_data_in_compile_data = ctx.attr._incompatible_do_not_include_data_in_compile_data[IncompatibleFlagInfo].enabled,
+        _incompatible_do_not_transform_sources = ctx.attr._incompatible_do_not_transform_sources[IncompatibleFlagInfo].enabled,
         _no_std = no_std,
         _codegen_units = ctx.attr._codegen_units[BuildSettingInfo].value,
         _experimental_use_allocator_libraries_with_mangled_symbols = ctx.attr.experimental_use_allocator_libraries_with_mangled_symbols,
@@ -969,6 +970,10 @@ rust_toolchain = rule(
             default = Label("//rust/settings:incompatible_do_not_include_data_in_compile_data"),
             doc = "Label to a boolean build setting that controls whether to include data files in compile_data.",
         ),
+        "_incompatible_do_not_transform_sources": attr.label(
+            default = Label("//rust/settings:incompatible_do_not_transform_sources"),
+            doc = "Label to a boolean build setting that controls whether to transform source files.",
+        ),
         "_no_std": attr.label(
             default = Label("//rust/settings:no_std"),
         ),