Add a gh-action and buildomat jobs to cargo check on no-default-features and feature-powerset

.cargo/config.toml

@@ -8,6 +8,7 @@
 # CI scripts:
 # - .github/buildomat/build-and-test.sh
 # - .github/buildomat/jobs/clippy.sh
+# - .github/buildomat/jobs/check-features.sh
 # - .github/workflows/rust.yml
 #
 [build]

.github/buildomat/jobs/check-features.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+#:
+#: name = "check-features (helios)"
+#: variety = "basic"
+#: target = "helios-2.0"
+#: rust_toolchain = true
+#: output_rules = [
+#:  "/out/*",
+#: ]
+
+# Run the check-features `xtask` on illumos, testing compilation of feature combinations.
+
+set -o errexit
+set -o pipefail
+set -o xtrace
+
+cargo --version
+rustc --version
+
+#
+# Set up our PATH for use with this workspace.
+#
+source ./env.sh
+export PATH="$PATH:$PWD/out/cargo-hack"
+
+banner prerequisites
+ptime -m bash ./tools/install_builder_prerequisites.sh -y
+
+#
+# Check feature combinations with the `cargo xtask check-features` command.
+#
+banner hack-check
+export CARGO_INCREMENTAL=0
+ptime -m timeout 2h cargo xtask check-features --ci

.github/buildomat/jobs/clippy.sh

@@ -10,7 +10,7 @@
 # (that we want to check) is conditionally-compiled on illumos only.
 #
 # Note that `cargo clippy` includes `cargo check, so this ends up checking all
-# of our code.
+# of our (default) code.
 
 set -o errexit
 set -o pipefail

.github/workflows/rust.yml

@@ -53,7 +53,7 @@ jobs:
       run: cargo run --bin omicron-package -- -t default check
 
   # Note that `cargo clippy` includes `cargo check, so this ends up checking all
-  # of our code.
+  # of our (default) code.
   clippy-lint:
     runs-on: ubuntu-22.04
     env:
@@ -82,6 +82,36 @@ jobs:
     - name: Run Clippy Lints
       run: cargo xtask clippy
 
+  check-features:
+    runs-on: ubuntu-22.04
+    env:
+      CARGO_INCREMENTAL: 0
+    steps:
+    # This repo is unstable and unnecessary: https://github.com/microsoft/linux-package-repositories/issues/34
+    - name: Disable packages.microsoft.com repo
+      run: sudo rm -f /etc/apt/sources.list.d/microsoft-prod.list
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        ref: ${{ github.event.pull_request.head.sha }} # see omicron#4461
+    - uses: Swatinem/rust-cache@23bce251a8cd2ffc3c1075eaa2367cf899916d84 # v2.7.3
+      if: ${{ github.ref != 'refs/heads/main' }}
+    - name: Report cargo version
+      run: cargo --version
+    - name: Update PATH
+      run: |
+        set -x
+        export PATH="./out/cargo-hack:$PATH"
+        source "./env.sh"; echo "PATH=$PATH" >> "$GITHUB_ENV"
+    - name: Print PATH
+      run: echo $PATH
+    - name: Print GITHUB_ENV
+      run: cat "$GITHUB_ENV"
+    - name: Install Pre-Requisites
+      run: ./tools/install_builder_prerequisites.sh -y
+    - name: Run Check on Feature Combinations (Feature-Powerset, No-Dev-Deps)
+      timeout-minutes: 120 # 2 hours
+      run: cargo xtask check-features --ci
+
   # This is just a test build of docs.  Publicly available docs are built via
   # the separate "rustdocs" repo.
   build-docs:

README.adoc

@@ -112,6 +112,21 @@ cargo nextest run
 
 We check that certain system library dependencies are not leaked outside of their intended binaries via `cargo xtask verify-libraries` in CI. If you are adding a new dependency on a illumos/helios library it is recommended that you update xref:.cargo/xtask.toml[] with an allow list of where you expect the dependency to show up. For example some libraries such as `libnvme.so.1` are only available in the global zone and therefore will not be present in any other zone. This check is here to help us catch any leakage before we go to deploy on a rack. You can inspect a compiled binary in the target directory for what it requires by using `elfedit` - for example `elfedit -r -e 'dyn:tag NEEDED' /path/to/omicron/target/debug/sled-agent`.
 
+=== Checking feature flag combinations
+
+To ensure that varying combinations of features compile, run `cargo xtask check-features`, which executes the https://github.com/taiki-e/cargo-hack[`cargo hack`] subcommand under the hood.
+
+This `xtask` is run in CI using the `--ci` parameter , which automatically exludes certain `image-*` features that purposefully cause compiler errors if set and uses a pre-built binary.
+
+If `cargo hack` is not already installed in omicron's `out/` directory, a pre-built binary will be installed automatically depending on your operating system and architecture.
+
+To limit the max number of simultaneous feature flags combined for checking, run the `xtask` with the `--depth <NUM>` flag:
+
+[source,text]
+----
+$ cargo xtask check-features --depth 2
+----
+
 === Rust packages in Omicron
 
 NOTE: The term "package" is overloaded: most programming languages and operating systems have their own definitions of a package.  On top of that, Omicron bundles up components into our own kind of "package" that gets delivered via the install and update systems.  These are described in the `package-manifest.toml` file in the root of the repo.  In this section, we're just concerned with Rust packages.

dev-tools/xtask/src/check_features.rs

@@ -0,0 +1,212 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//! Subcommand: cargo xtask check-features
+
+use anyhow::{bail, Result};
+use camino::Utf8PathBuf;
+use clap::Parser;
+use std::{collections::HashSet, process::Command};
+
+const SUPPORTED_ARCHITECTURES: [&str; 1] = ["x86_64"];
+const CI_EXCLUDED_FEATURES: [&str; 2] = ["image-trampoline", "image-standard"];
+
+#[derive(Parser)]
+pub struct Args {
+    /// Run in CI mode, with a default set of features excluded.
+    #[clap(long, default_value_t = false)]
+    ci: bool,
+    /// Features to exclude from the check.
+    #[clap(long, value_name = "FEATURES")]
+    exclude_features: Option<Vec<String>>,
+    /// Depth of the feature powerset to check.
+    #[clap(long, value_name = "NUM")]
+    depth: Option<usize>,
+    /// Error format passed to `cargo hack check`.
+    #[clap(long, value_name = "FMT")]
+    message_format: Option<String>,
+    /// Version of `cargo-hack` to install. By default, we download a pre-built
+    /// version.
+    #[clap(long, value_name = "VERSION")]
+    install_version: Option<String>,
+}
+
+/// Run `cargo hack check`.
+pub fn run_cmd(args: Args) -> Result<()> {
+    // We cannot specify both `--ci` and `--install-version`, as the former
+    // implies we are using a pre-built version.
+    if args.ci && args.install_version.is_some() {
+        bail!("cannot specify --ci and --install-version together");
+    }
+
+    let cargo =
+        std::env::var("CARGO").unwrap_or_else(|_| String::from("cargo"));
+
+    let mut command = Command::new(&cargo);
+
+    // Add the `hack check` subcommand.
+    command.args(&["hack", "check"]);
+
+    if args.ci {
+        install_prebuilt_cargo_hack(&cargo)?;
+
+        let ex = if let Some(mut features) = args.exclude_features {
+            // Extend the list of features to exclude with the CI defaults.
+            features.extend(
+                CI_EXCLUDED_FEATURES.into_iter().map(|s| s.to_string()),
+            );
+
+            // Remove duplicates.
+            let excludes = features.into_iter().collect::<HashSet<_>>();
+
+            excludes.into_iter().collect::<Vec<_>>().join(",")
+        } else {
+            CI_EXCLUDED_FEATURES.join(",")
+        };
+
+        // Add the `--exclude-features` flag if we are running in CI mode.
+        command.args(["--exclude-features", &ex]);
+    } else {
+        install_cargo_hack(&cargo, args.install_version)?;
+        // Add "only" the `--exclude-features` flag if it was provided.
+        if let Some(features) = args.exclude_features {
+            command.args(["--exclude-features", &features.join(",")]);
+        }
+    }
+
+    if let Some(depth) = args.depth {
+        command.args(&["--depth", &depth.to_string()]);
+    }
+
+    // Pass along the `--message-format` flag if it was provided.
+    if let Some(fmt) = args.message_format {
+        command.args(["--message-format", &fmt]);
+    }
+
+    command
+        // Make sure we check everything.
+        .arg("--workspace")
+        // We want to check the binaries.
+        .arg("--bins")
+        // We want to check the feature powerset.
+        .arg("--feature-powerset")
+        // We will not check the dev-dependencies, which should covered by tests.
+        .arg("--no-dev-deps");
+
+    exec(command)
+}
+
+/// The supported operating systems.
+enum Os {
+    Illumos,
+    Linux,
+    Mac,
+}
+
+/// Get the current OS.
+fn os_name() -> Result<Os> {
+    let os = match std::env::consts::OS {
+        "linux" => Os::Linux,
+        "macos" => Os::Mac,
+        "solaris" | "illumos" => Os::Illumos,
+        other => bail!("OS not supported: {other}"),
+    };
+    Ok(os)
+}
+
+/// This is a workaround for the lack of a CARGO_WORKSPACE_DIR environment
+/// variable, as suggested in <https://github.com/rust-lang/cargo/issues/3946#issuecomment-1433384192>.
+/// A better workaround might be to set this in the `[env]` section of
+/// `.cargo/config.toml`.
+fn project_root() -> Utf8PathBuf {
+    Utf8PathBuf::from(&concat!(env!("CARGO_MANIFEST_DIR"), "/.."))
+}
+
+/// Get the path to the `out` directory from the project root/workspace
+/// directory.
+fn out_dir() -> Utf8PathBuf {
+    project_root().join("out/cargo-hack")
+}
+
+/// Install `cargo-hack` if the `install-version` was specified; otherwise,
+/// download a pre-built version if it's not already in our `out` directory.
+fn install_cargo_hack(cargo: &str, version: Option<String>) -> Result<()> {
+    if let Some(version) = version {
+        let mut command = Command::new(cargo);
+
+        eprintln!(
+            "installing cargo-hack at version {} to {}",
+            version,
+            env!("CARGO_HOME")
+        );
+        command.args(&["install", "cargo-hack", "--version", &version]);
+        exec(command)
+    } else if !out_dir().exists() {
+        install_prebuilt_cargo_hack(cargo)
+    } else {
+        let out_dir = out_dir();
+        eprintln!("cargo-hack found in {}", out_dir);
+        Ok(())
+    }
+}
+
+/// Download a pre-built version of `cargo-hack` to the `out` directory via the
+/// download `xtask`.
+fn install_prebuilt_cargo_hack(cargo: &str) -> Result<()> {
+    let mut command = Command::new(cargo);
+
+    let out_dir = out_dir();
+    eprintln!(
+        "cargo-hack not found in {}, downloading a pre-built version",
+        out_dir
+    );
+
+    let os = os_name()?;
+    match os {
+        Os::Illumos | Os::Linux | Os::Mac
+            if SUPPORTED_ARCHITECTURES.contains(&std::env::consts::ARCH) =>
+        {
+            // Download the pre-built version of `cargo-hack` via our
+            // download `xtask`.
+            command.args(&["xtask", "download", "cargo-hack"]);
+        }
+        _ => {
+            bail!(
+                "cargo-hack is not pre-built for this os {} / arch {}",
+                std::env::consts::OS,
+                std::env::consts::ARCH
+            );
+        }
+    }
+
+    exec(command)
+}
+
+/// Execute the command and check the exit status.
+fn exec(mut command: Command) -> Result<()> {
+    let cargo =
+        std::env::var("CARGO").unwrap_or_else(|_| String::from("cargo"));
+
+    eprintln!(
+        "running: {:?} {}",
+        &cargo,
+        command
+            .get_args()
+            .map(|arg| format!("{:?}", arg.to_str().unwrap()))
+            .collect::<Vec<_>>()
+            .join(" ")
+    );
+
+    let exit_status = command
+        .spawn()
+        .expect("failed to spawn child process")
+        .wait()
+        .expect("failed to wait for child process");
+
+    if !exit_status.success() {
+        bail!("cargo-hack install failed: {}", exit_status);
+    }
+
+    Ok(())
+}