Re-stabilize build-dir layout v2 by ranger-ross · Pull Request #17354 · rust-lang/cargo

ranger-ross · 2026-08-12T17:20:29Z

What does this PR try to resolve?

This PR restabilizes the new build-dir layout tracked in #15010.

The previous stablization in #16807 was rolled back due to performance and scaling issues discovered on nightly.
These issues were mitigated in #17191, #17168, and #17236.

The new layout was re-enabled on nightly in #17258 and there has been no reported issues. Many tools have started migrating and the majority of well known tools have already added support for the new build-dir layout.

closes #15010

How to test and review this PR?

cargo test and the new layout has been enabled on nightly for ~2 weeks.

ranger-ross · 2026-08-12T18:06:16Z

I think all tests should be passing now except profile_trim_paths::unremap_file_with_cargo_clean.

I believe the target/debug/foo.trim-paths.jsonl file was previously getting removed with cargo clean -p foo -Ztrim-paths, but is not getting removed when the new build-dir layout is enabled.

So its hitting this assert:

assert!(!unremap_file_path(&p.bin("foo")).exists());

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What is the intended behavior here? Does cargo clean -p foo remove target/debug/foo on both old and new build layout?

yeah, wasn't fully sure. So I left it failing for now.

If the trim paths artifacts is generated for crate foo and you clean the foo crate it seems reasonable to me to expect that file to be removed.

Yeah I would expect that. The foo.trim-paths.jsonl is a companion file for the root binary unit, similar to pdb on Windows, dSYM on macOS, and dwp/dwo file on Linux.

Posted #17356 for this :D

epage · 2026-08-12T18:37:49Z

Blocked until at least August 14th to be after beta branch: https://forge.rust-lang.org/

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epage · 2026-08-12T18:38:18Z

Is there anything different in this stabilization PR compared to the previous one?

ranger-ross · 2026-08-13T03:26:43Z

Is there anything different in this stabilization PR compared to the previous one?

It should be largely the same with the following differences:

We no longer have the ugly impl Default for CliUnstable
There were new tests that were recently added that needed to be updated
Due to 80f7382 there were more -L dependency= args removed than the previous PR.

@weihanglo

…ut (rust-lang#17356) ### What does this PR try to resolve? See rust-lang#17354 (comment) for the motivating context. In rust-lang#17303 we started emitting unremap files to final artifacts. This included logic for cleaning the unremap file when running `cargo clean -p` but the logic was not added in the `.build_dir_new_layout` branch in the cargo clean logic. This PR adds the logic to both branches. ### How to test and review this PR? Primarily using the existing tests r? @weihanglo

weihanglo · 2026-08-17T21:50:47Z

FYI, branch promotion is done.

rustbot · 2026-08-18T00:15:32Z

r? @epage

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Owners of files modified in this PR: @epage, @weihanglo
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weihanglo

We have FCP already in #16807 (comment). I don't think we need a new one.

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weihanglo · 2026-08-18T01:35:23Z


 Caused by:
-  process didn't exit successfully: `[ROOT]/foo/target/debug/build/foo-[HASH]/build-script-build1` ([EXIT_STATUS]: 101)
+  process didn't exit successfully: `[ROOT]/foo/target/debug/build/foo/[HASH]/out/build_script_build1` ([EXIT_STATUS]: 101)


I forgot why this executable name changed. Could you remind me?

See #16812

The TL;DR is that the build_script_build.exe always existed, but we would "uplift" it to the same directory with the kebab cased name + -Cextra-filename. Since the hash is in the directory path, -Cextra-filename is not needed. So we were just renaming the script from snake to kebab case, which felt unnecessary so we removed that step to keep it simple.

Update cargo submodule 3 commits in 8a0d8afba810304bcf9a10bac430be80dd470233..36e1162a7989dd1d11b75bfa90283efcbf162cac 2026-08-15 01:32:53 +0000 to 2026-08-18 02:35:44 +0000 - Re-stabilize build-dir layout v2 (rust-lang/cargo#17354) - Enable `-Zembed-metadata=no` by default on nightly Cargo (rust-lang/cargo#17267) - fix(frontmatter): Don't panic on a short closing fence before a non-ASCII char (rust-lang/cargo#17274) r? ghost

Update cargo submodule 6 commits in 8a0d8afba810304bcf9a10bac430be80dd470233..514c56dd7321eecbfdcf9b6479519cf4edfab906 2026-08-15 01:32:53 +0000 to 2026-08-19 00:31:04 +0000 - fix(git): `git gc` with `safe.bareRepository=explicit` (rust-lang/cargo#17370) - test: make snapshots agnostic to `-Zembed-metadata=no` (rust-lang/cargo#17374) - fix(clean): Improving description for clean options (rust-lang/cargo#17365) - Re-stabilize build-dir layout v2 (rust-lang/cargo#17354) - Enable `-Zembed-metadata=no` by default on nightly Cargo (rust-lang/cargo#17267) - fix(frontmatter): Don't panic on a short closing fence before a non-ASCII char (rust-lang/cargo#17274)

rustbot added A-documenting-cargo-itself Area: Cargo's documentation A-testing-cargo-itself Area: cargo's tests A-unstable Area: nightly unstable support labels Aug 12, 2026

ranger-ross force-pushed the restablize-build-dir-new-layout branch 2 times, most recently from be983b0 to cb74501 Compare August 12, 2026 18:02

ranger-ross commented Aug 12, 2026

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epage reviewed Aug 12, 2026

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ranger-ross mentioned this pull request Aug 13, 2026

Remove unremap file when running cargo clean -p in new build-dir layout #17356

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rustbot added the S-waiting-on-author Status: The marked PR is awaiting some action (such as code changes) from the PR author. label Aug 13, 2026

ranger-ross force-pushed the restablize-build-dir-new-layout branch 4 times, most recently from 59957dc to ede4285 Compare August 14, 2026 09:13

feat: Re-stabilize build-dir layout v2

efb0721

ranger-ross force-pushed the restablize-build-dir-new-layout branch from ede4285 to efb0721 Compare August 14, 2026 13:01

weihanglo approved these changes Aug 16, 2026

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ranger-ross marked this pull request as ready for review August 18, 2026 00:15

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Aug 18, 2026

rustbot assigned epage Aug 18, 2026

weihanglo approved these changes Aug 18, 2026

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weihanglo added this pull request to the merge queue Aug 18, 2026

Merged via the queue into rust-lang:master with commit 36e1162 Aug 18, 2026
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rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Aug 18, 2026

This was referenced Aug 18, 2026

feat(diag): Stabilize cargo-lints #17298

Open

feat(resolver): Stabilize min-publish-age #17335

Open

weihanglo mentioned this pull request Aug 18, 2026

Update cargo submodule rust-lang/rust#161273

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weihanglo added the relnotes Release-note worthy label Aug 18, 2026

rustbot added this to the 1.100.0 milestone Aug 19, 2026

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