Move `std::io::buffered` to `alloc::io` by bushrat011899 · Pull Request #158547 · rust-lang/rust

bushrat011899 · 2026-06-29T05:48:35Z

ACP: rust-lang/libs-team#755
Tracking issue: #154046
Split From: #156527
~~Blocked On: #158546~~

Description

Moves std::io::BufReader/BufWriter/LineWriter/etc. to alloc::io. This is effectively a direct cut and paste. Blocked on #158546.

Notes

No AI tooling of any kind was used during the creation of this PR.
Please see Tracking Issue for alloc::io and core::io #154046 (comment) for a review order and broader context for this PR.

rustbot · 2026-06-29T05:48:41Z

r? @JohnTitor

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Owners of files modified in this PR: @ChrisDenton, libs
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bushrat011899 · 2026-06-29T05:48:45Z

@rustbot blocked

Co-Authored-By: Clar Fon <15850505+clarfonthey@users.noreply.github.com>

clarfonthey · 2026-07-20T12:14:41Z

Small comment on the new constructors, otherwise looks good.

bushrat011899 · 2026-07-20T12:19:53Z

Small comment on the new constructors, otherwise looks good.

Yeah makes sense, I've added a basic #[inline] to both functions. Normally I'd just amend the relevant commits but I'm using the mobile app from bed right now lol

clarfonthey · 2026-07-20T12:27:38Z

All good! Time zones strike again.

@bors try
@rust-timer queue

Move `std::io::buffered` to `alloc::io`

rust-bors · 2026-07-20T14:22:23Z

☀️ Try build successful (CI)
Build commit: b404afe (b404afe496973d61ac2deb36a68e7664b110decd)
Base parent: 14ead7d (14ead7d3d509f50efe9afb84673e65885dfd4d07)

rust-timer · 2026-07-20T15:11:37Z

Finished benchmarking commit (b404afe): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

Results (primary 2.9%, secondary 0.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	6.6%	[6.6%, 6.6%]	1
Regressions ❌ (secondary)	5.9%	[4.6%, 7.2%]	4
Improvements ✅ (primary)	-0.9%	[-0.9%, -0.9%]	1
Improvements ✅ (secondary)	-4.5%	[-6.5%, -3.1%]	4
All ❌✅ (primary)	2.9%	[-0.9%, 6.6%]	2

Cycles

Results (primary -0.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.0%	[2.0%, 2.0%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.1%	[-3.1%, -3.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.5%	[-3.1%, 2.0%]	2

Binary size

Results (primary 0.0%, secondary 0.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.0%	[0.0%, 0.0%]	4
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.0%]	4

Bootstrap: 485.673s -> 485.443s (-0.05%)
Artifact size: 391.74 MiB -> 392.41 MiB (0.17%)

clarfonthey · 2026-07-20T17:49:21Z

@bors r+ rollup

rust-bors · 2026-07-20T17:49:24Z

📌 Commit 6ef1cf3 has been approved by clarfonthey

It is now in the queue for this repository.

…=clarfonthey Move `std::io::buffered` to `alloc::io` ACP: rust-lang/libs-team#755 Tracking issue: rust-lang#154046 Split From: rust-lang#156527 ~~Blocked On: rust-lang#158546 ## Description Moves `std::io::BufReader`/`BufWriter`/`LineWriter`/etc. to `alloc::io`. This is effectively a direct cut and paste. Blocked on rust-lang#158546. --- ## Notes * No AI tooling of any kind was used during the creation of this PR. * Please see rust-lang#154046 (comment) for a review order and broader context for this PR.

…uwer Rollup of 7 pull requests Successful merges: - #159582 (Sync from portable simd 2026 07 20) - #157270 (ergonomic_clones_dotuse_capture_by_ref: Capture upvar by ref for `.use` in non-move closures) - #158496 (Move `check_rustc_pub_transparent` into the attribute parser) - #158547 (Move `std::io::buffered` to `alloc::io`) - #159505 (make rustdoc::bare_urls strip trailing periods from url) - #159578 (Extract coroutine closure helper functions) - #159613 (Set the rustc lib path for unstable-book-gen)

…=clarfonthey Move `std::io::buffered` to `alloc::io` ACP: rust-lang/libs-team#755 Tracking issue: rust-lang#154046 Split From: rust-lang#156527 ~~Blocked On: rust-lang#158546 ## Description Moves `std::io::BufReader`/`BufWriter`/`LineWriter`/etc. to `alloc::io`. This is effectively a direct cut and paste. Blocked on rust-lang#158546. --- ## Notes * No AI tooling of any kind was used during the creation of this PR. * Please see rust-lang#154046 (comment) for a review order and broader context for this PR.

rustbot assigned JohnTitor Jun 29, 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 Jun 29, 2026

rustbot added S-blocked Status: Blocked on something else such as an RFC or other implementation work. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 29, 2026

This was referenced Jun 29, 2026

Tracking Issue for alloc::io and core::io #154046

Open

Move std::io::copy to alloc::io #158548

Open

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bushrat011899 force-pushed the alloc_io_buffered branch from 999bae7 to ed009e7 Compare July 2, 2026 02:01

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bushrat011899 force-pushed the alloc_io_buffered branch 2 times, most recently from dd63a8f to bc8b452 Compare July 3, 2026 03:48

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bushrat011899 force-pushed the alloc_io_buffered branch from bc8b452 to 62c2a52 Compare July 6, 2026 09:28

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bushrat011899 and others added 3 commits July 20, 2026 17:14

Use Vec::<u8>::try_extend_from_slice_of_bytes instead of unsafe code

295f7f4

Co-Authored-By: Clar Fon <15850505+clarfonthey@users.noreply.github.com>

Make Buffer private

3739d04

Standardize on pub(super) instead of pub(in crate::io)

69b3806

Co-Authored-By: Clar Fon <15850505+clarfonthey@users.noreply.github.com>

bushrat011899 force-pushed the alloc_io_buffered branch from ae73c49 to 69b3806 Compare July 20, 2026 07:15

clarfonthey reviewed Jul 20, 2026

View reviewed changes

Comment thread library/alloc/src/io/buffered/bufreader.rs

clarfonthey reviewed Jul 20, 2026

View reviewed changes

Comment thread library/alloc/src/io/buffered/bufwriter.rs

bushrat011899 commented Jul 20, 2026

View reviewed changes

Comment thread library/alloc/src/io/buffered/bufreader.rs

Comment thread library/alloc/src/io/buffered/bufwriter.rs

bushrat011899 added 2 commits July 20, 2026 22:16

Add inline to new BufReader method

9d38fe5

Add inline to new BufWriter method

6ef1cf3

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 20, 2026

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rust-bors Bot pushed a commit that referenced this pull request Jul 20, 2026

Auto merge of #158547 - bushrat011899:alloc_io_buffered, r=<try>

b404afe

Move `std::io::buffered` to `alloc::io`

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 20, 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-review Status: Awaiting review from the assignee but also interested parties. labels Jul 20, 2026

JonathanBrouwer mentioned this pull request Jul 20, 2026

Rollup of 7 pull requests #159622

Closed

jhpratt mentioned this pull request Jul 21, 2026

Rollup of 14 pull requests #159634

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rust-timer commented Jul 20, 2026

Overall result: no relevant changes - no action needed

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bushrat011899 commented Jun 29, 2026 •

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