Replace custom trim_ascii_start with the standard library method by thebabalola · Pull Request #155134 · rust-lang/rust

thebabalola · 2026-04-10T23:35:23Z

The markdown parser in rustc_errors has a local trim_ascii_start function that strips leading ASCII whitespace from a byte slice. The standard library has had <[u8]>::trim_ascii_start() since Rust 1.80, which does the same thing.

This PR removes the custom function and calls the stdlib method directly in parse_unordered_li and parse_ordered_li. No behaviour change.

I also added a test covering the list item leading-whitespace trimming behaviour, including a tab case.

Fixes rustfoundation/interop-initiative#53

rustbot · 2026-04-10T23:35:29Z

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mati865 · 2026-04-12T12:53:44Z

+    assert_eq!(t, MdTree::UnorderedListItem(vec![MdTree::PlainText("hello")].into()));
+    assert_eq!(r, b"");
+
+    // tab after the marker space — needs #[rustfmt::skip] or rustfmt removes it


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I doubt rustfmt would rewrite string like that and I cannot reproduce the problem, how did you run into that?

You're right, I actually added the #[rustfmt::skip] out of caution after seeing a note in the tracking issue about rustfmt removing unusual whitespace. But since the tab is written as \t in the string literal (not a literal tab character), rustfmt won't touch it. I'll just remove the attribute.

Please squash the commit and update the description.

Please squash the commit and update the description.

@thebabalola do you need help with squashing commits?

@rustbot author

@teor2345 ... Already done, squashed to 2 commits and force pushed earlier. Thanks for checking..

mati865 · 2026-04-12T12:53:55Z

@rustbot author

rustbot · 2026-04-12T12:54:01Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

thebabalola · 2026-04-13T03:24:02Z

@rustbot ready

The local trim_ascii_start function in the markdown parser duplicates <[u8]>::trim_ascii_start() from the standard library (stable since 1.80). Remove the custom function and call the stdlib method directly. No behaviour change. Fixes rustfoundation/interop-initiative#53

thebabalola · 2026-04-13T22:08:08Z

@rustbot ready

mati865 · 2026-04-14T12:55:46Z

Great, thanks!

@bors r+

rust-bors · 2026-04-14T12:55:49Z

📌 Commit fdfdb08 has been approved by mati865

It is now in the queue for this repository.

…-start-with-stdlib, r=mati865 Replace custom trim_ascii_start with the standard library method The markdown parser in `rustc_errors` has a local `trim_ascii_start` function that strips leading ASCII whitespace from a byte slice. The standard library has had `<[u8]>::trim_ascii_start()` since Rust 1.80, which does the same thing. This PR removes the custom function and calls the stdlib method directly in `parse_unordered_li` and `parse_ordered_li`. No behaviour change. I also added a test covering the list item leading-whitespace trimming behaviour, including a tab case. Fixes rustfoundation/interop-initiative#53

…uwer Rollup of 7 pull requests Successful merges: - #154049 (delegation: Track more precise spans for glob delegations) - #155134 (Replace custom trim_ascii_start with the standard library method) - #155235 (add the `fma4` x86 target feature) - #155218 (coroutines: Skip the closure signature annotation check for tainted bodies) - #155274 (limit duplicate-profiler-builtins test to targets that can do dynamic linking) - #155276 (`#[rustc_must_match_exhaustively]` detect let else) - #155281 (Revert "allow `windows-gnu` targets to embed gdb visualizer scripts")

Rollup merge of #155134 - thebabalola:fix/replace-trim-ascii-start-with-stdlib, r=mati865 Replace custom trim_ascii_start with the standard library method The markdown parser in `rustc_errors` has a local `trim_ascii_start` function that strips leading ASCII whitespace from a byte slice. The standard library has had `<[u8]>::trim_ascii_start()` since Rust 1.80, which does the same thing. This PR removes the custom function and calls the stdlib method directly in `parse_unordered_li` and `parse_ordered_li`. No behaviour change. I also added a test covering the list item leading-whitespace trimming behaviour, including a tab case. Fixes rustfoundation/interop-initiative#53

rustbot assigned mati865 Apr 10, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Apr 10, 2026

thebabalola mentioned this pull request Apr 10, 2026

Outreachy tracking issue for Rust whitespace check bugs rustfoundation/interop-initiative#53

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mati865 reviewed Apr 12, 2026

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rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 12, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 13, 2026

thebabalola added 2 commits April 13, 2026 23:07

Add test for list item leading whitespace trimming

1e02a2b

thebabalola force-pushed the fix/replace-trim-ascii-start-with-stdlib branch from 1fa81a8 to fdfdb08 Compare April 13, 2026 22:07

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 13, 2026

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 14, 2026

This was referenced Apr 14, 2026

Rollup of 5 pull requests #155288

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Rollup of 7 pull requests #155292

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rust-bors Bot merged commit 5da0b6c into rust-lang:main Apr 14, 2026
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rustbot added this to the 1.97.0 milestone Apr 14, 2026

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