Split build-dir lock into dedicated lock #16708
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epage merged 1 commit intorust-lang:masterfrom Mar 6, 2026
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This commit seperates the `build-dir` and `artifact-dir` locks so that an exclusive lock on `artifact-dir` does not force an exclusive lock on `build-dir` and vise-versa. The motivation of this change is for fine grain locking to work even when `build-dir` == `artifact-dir`
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Should we also rename .cargo-lock to .cargo-artifact-lock?
That could negatively impact cross-version builds.
Which gets me thinking, does this PR negatively impact cross-version builds?
- this only impacts users who have a shared artifact and build dir
- this only impacts users who grab only the build dir lock
- this only impacts state that is not scoped by the hash of the cargo/rustc version
That seems relatively small
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this only impacts state that is not scoped by the hash of the cargo/rustc version
The most common scenario that hash may collides is using different nightly toolchains, though
- Rustc bootstrap IIRC doesn't run different nightly in paralell
- Tools like
cargo-bisect-rustcruns in serial.
Agree with the analysis!
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weihanglo
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this only impacts state that is not scoped by the hash of the cargo/rustc version
The most common scenario that hash may collides is using different nightly toolchains, though
- Rustc bootstrap IIRC doesn't run different nightly in paralell
- Tools like
cargo-bisect-rustcruns in serial.
Agree with the analysis!
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Update cargo submodule 21 commits in 90ed291a50efc459e0c380d7b455777ed41c6799..cbb9bb8bd0fb272b1be0d63a010701ecb3d1d6d3 2026-03-05 15:11:25 +0000 to 2026-03-13 14:34:16 +0000 - fix(git): preserve SCP-like submodule URLs for fetch (rust-lang/cargo#16744) - Fix 16732 (rust-lang/cargo#16746) - fix(rustdoc): switch to new `--emit` options (rust-lang/cargo#16739) - fix(git): convert SCP-like submodule URLs to ssh:// format (rust-lang/cargo#16727) - fix(core): typo (rust-lang/cargo#16738) - CARGO_TARGET_DIR doesn't have to be relative (rust-lang/cargo#16735) - chore(ci): Detect user changes to src/etc/man (rust-lang/cargo#16736) - util: Exclude from iCloud Drive sync on macOS (rust-lang/cargo#16728) - fix(compile): Stop on denying warnings without --keep-going (rust-lang/cargo#16725) - feat(shell): Support OSC 9;4 progress on ptyxis (rust-lang/cargo#16730) - Let git decide when to run gc (rust-lang/cargo#16459) - chore(deps): update cargo-semver-checks to v0.47.0 (rust-lang/cargo#16723) - fix(compile): Turn warning summaries into errors also (rust-lang/cargo#16721) - fix(fix): Switch from ad-hoc to structured warnings (rust-lang/cargo#16711) - fix: ignore implicit std dependencies in `unused-crate-dependencies` lint (rust-lang/cargo#16677) - chore(deps): update msrv (3 versions) to v1.92 (rust-lang/cargo#16716) - chore(deps): update msrv (1 version) to v1.94 (rust-lang/cargo#16710) - fix(script): surpress `unused_features` lint for embedded (rust-lang/cargo#16714) - Split `build-dir` lock into dedicated lock (rust-lang/cargo#16708) - Add missing truncate when writing .crate files (rust-lang/cargo#16688) - refactor(fix): Prep for annotate-snippets (rust-lang/cargo#16702)
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What does this PR try to resolve?
This PR separates the
build-dirandartifact-dirlocks so that an exclusive lock onartifact-dirdoes not force an exclusive lock onbuild-dirand vise-versa.The motivation of this change is for fine grain locking to work even when
build-dir==artifact-dir(the default)However, note that this does NOT feature gate the lock file renaming as build-dir is not considered to be part of the public interface of Cargo.
Tracking issue: #4282
How to test and review this PR?
See the updated tests in
build_dir.rsAlso note that while testing this change I discovered a separate bug around
cargo package.For now I opened a separate issue (#16707) added a FIXME to make it clear that the tests describe the current behavior, its not ideal.
Open Questions
.cargo-build-lock?.cargo-prefix would be nice for consistency..cargo-lockto.cargo-artifact-lock?r? @epage