Add is_disconnected functions to mpsc and mpmc channels by LevitatingBusinessMan · Pull Request #153170 · rust-lang/rust

LevitatingBusinessMan · 2026-02-27T08:38:53Z

Add is_disconnected() functions to the Sender and Receiver of both mpmc an mpsc channels.

std::sync::mpmc::Sender<T>::is_disconnected(&self) -> bool
std::sync::mpmc::Receiver<T>::is_disconnected(&self) -> bool

std::sync::mpsc::Sender<T>::is_disconnected(&self) -> bool
std::sync::mpsc::Receiver<T>::is_disconnected(&self) -> bool

The mpsc methods are locked behind the mpsc_is_disconnected feature gate, which has no tracking issue yet.

ACP: rust-lang/libs-team#748
Tracking issue: #153668

rustbot · 2026-02-27T08:38:58Z

r? @Mark-Simulacrum

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LevitatingBusinessMan · 2026-02-27T08:40:59Z

@rustbot label +S-waiting-on-ACP

a1phyr

I think that it the doc should mention that if is_disconnected returns false, it does not guaranty anything in the future (eg a send/recv just after might fail anything).

This footgun can cause race conditions, so it should be documented.

View changes since this review

LevitatingBusinessMan · 2026-02-28T18:57:15Z

This footgun can cause race conditions, so it should be documented.

I added the following text to the documentation:

/// Note that a return value of `false` does not guarantee the channel will
/// remain connected. The channel may be disconnected immediately after this method
/// returns, so a subsequent [`Sender::send`] may still fail with [`SendError`].

and subsequent versions for Receiver.

LevitatingBusinessMan · 2026-03-10T18:22:20Z

@rustbot label +S-waiting-on-review -S-waiting-on-ACP

LevitatingBusinessMan · 2026-03-10T18:23:44Z

Currently I've put the methods for mpmc behind #![feature(mpmc_channel)]. Somebody should tell me if that's a good idea, or that both variants should be gated behind the same feature.

Mark-Simulacrum · 2026-03-19T02:33:01Z

@bors r+ rollup

I think it seems reasonable either way but this setup seems fine for the feature gate.

rust-bors · 2026-03-19T02:33:05Z

📌 Commit ce2de64 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

…ted, r=Mark-Simulacrum Add is_disconnected functions to mpsc and mpmc channels Add `is_disconnected()` functions to the `Sender` and `Receiver` of both `mpmc` an `mpsc` channels. ```rust std::sync::mpmc::Sender<T>::is_disconnected(&self) -> bool std::sync::mpmc::Receiver<T>::is_disconnected(&self) -> bool std::sync::mpsc::Sender<T>::is_disconnected(&self) -> bool std::sync::mpsc::Receiver<T>::is_disconnected(&self) -> bool ``` The `mpsc` methods are locked behind the `mpsc_is_disconnected` feature gate, which has no tracking issue yet. ACP: rust-lang/libs-team#748 Tracking issue: rust-lang#153668

…uwer Rollup of 12 pull requests Successful merges: - #152870 (Do not enable split debuginfo for windows-gnu) - #153333 (Fix bootstrap rust build failure for vxworks) - #153681 (ci: add runners for vanilla LLVM 22) - #153824 (Add `Wake` diagnostic item for `alloc::task::Wake`) - #154077 (Optimize 128-bit integer formatting) - #154078 (`define_callbacks` tweaks) - #151905 (Split the `dec2flt::RawFloat` trait for easier reuse) - #153170 (Add is_disconnected functions to mpsc and mpmc channels) - #153804 (Derive Macro Eq: link to more detailed documentation) - #153974 (Point at return type when it is the source of the type expectation) - #154018 (simplify and remove `tests/ui/kindck` and related tests) - #154041 (bootstrap: Allow `--bless`ing changes to editor settings files)

…ted, r=Mark-Simulacrum Add is_disconnected functions to mpsc and mpmc channels Add `is_disconnected()` functions to the `Sender` and `Receiver` of both `mpmc` an `mpsc` channels. ```rust std::sync::mpmc::Sender<T>::is_disconnected(&self) -> bool std::sync::mpmc::Receiver<T>::is_disconnected(&self) -> bool std::sync::mpsc::Sender<T>::is_disconnected(&self) -> bool std::sync::mpsc::Receiver<T>::is_disconnected(&self) -> bool ``` The `mpsc` methods are locked behind the `mpsc_is_disconnected` feature gate, which has no tracking issue yet. ACP: rust-lang/libs-team#748 Tracking issue: rust-lang#153668

…uwer Rollup of 19 pull requests Successful merges: - #152870 (Do not enable split debuginfo for windows-gnu) - #153333 (Fix bootstrap rust build failure for vxworks) - #153681 (ci: add runners for vanilla LLVM 22) - #153727 (When single impl can satisfy inference error, suggest type) - #153824 (Add `Wake` diagnostic item for `alloc::task::Wake`) - #154077 (Optimize 128-bit integer formatting) - #154078 (`define_callbacks` tweaks) - #151905 (Split the `dec2flt::RawFloat` trait for easier reuse) - #153170 (Add is_disconnected functions to mpsc and mpmc channels) - #153308 (Add hygiene annotations for tokens in `macro_rules!` bodies) - #153557 (fix inference variables leaking into HIR const literal lowering logic) - #153804 (Derive Macro Eq: link to more detailed documentation) - #153913 (Fix some suggestions of the `for-loops-over-fallibles` lint) - #153974 (Point at return type when it is the source of the type expectation) - #153987 (mGCA: Lower const generic args to infer when needed) - #154018 (simplify and remove `tests/ui/kindck` and related tests) - #154036 (borrowck/type_check: remove helper left-over from unsized locals) - #154038 (merge `regions-outlives-nominal-type-*` tests into one file) - #154041 (bootstrap: Allow `--bless`ing changes to editor settings files)

rustbot assigned Mark-Simulacrum Feb 27, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Feb 27, 2026

LevitatingBusinessMan mentioned this pull request Feb 27, 2026

Add is_disconnected() to std::sync::mpsc and std::sync::mpmc rust-lang/libs-team#748

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Add is_disconnected functions to mpsc and mpmc channels

7adb9ba

LevitatingBusinessMan force-pushed the is_disconnected branch from c952a5b to 7adb9ba Compare February 27, 2026 08:46

rustbot added the S-waiting-on-ACP Status: PR has an ACP and is waiting for the ACP to complete. label Feb 27, 2026

a1phyr reviewed Feb 28, 2026

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Mark-Simulacrum removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 28, 2026

warn of possible race condition in channel is_disconnected doc

feef7b4

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 28, 2026

LevitatingBusinessMan requested a review from a1phyr February 28, 2026 19:09

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 28, 2026

LevitatingBusinessMan mentioned this pull request Mar 10, 2026

Tracking Issue for is_disconnected functions for mpsc and mpmc channels #153668

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assign mpsc_is_disconnected issue 153668

ce2de64

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-ACP Status: PR has an ACP and is waiting for the ACP to complete. labels Mar 10, 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 Mar 19, 2026

Zalathar mentioned this pull request Mar 19, 2026

Rollup of 20 pull requests #154079

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JonathanBrouwer mentioned this pull request Mar 19, 2026

Rollup of 20 pull requests #154080

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JonathanBrouwer mentioned this pull request Mar 19, 2026

Rollup of 12 pull requests #154083

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This was referenced Mar 19, 2026

Rollup of 20 pull requests #154091

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Rollup of 19 pull requests #154092

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rust-bors bot merged commit 981f837 into rust-lang:main Mar 19, 2026
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rustbot added this to the 1.96.0 milestone Mar 19, 2026

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Add is_disconnected functions to mpsc and mpmc channels#153170

Add is_disconnected functions to mpsc and mpmc channels#153170
rust-bors[bot] merged 3 commits intorust-lang:mainfrom
LevitatingBusinessMan:is_disconnected

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