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| author | Matthias Krüger <476013+matthiaskrgr@users.noreply.github.com> | 2025-04-09 20:23:09 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2025-04-09 20:23:09 +0200 |
| commit | d5f930fe76ab17ad5ccd4834f3cea10a99022cf2 (patch) | |
| tree | e214844f9b96ecbdde35edc8869fe56ce9363cae /library/std/src/sync | |
| parent | 3507f359b1167e90b6d447cb7add6890c7e6b0dc (diff) | |
| parent | 0162f29436d7992ca5f3b642a282045afd922a26 (diff) | |
| download | rust-d5f930fe76ab17ad5ccd4834f3cea10a99022cf2.tar.gz rust-d5f930fe76ab17ad5ccd4834f3cea10a99022cf2.zip | |
Rollup merge of #139164 - xizheyin:issue-139034, r=joboet
std: improve documentation for get_mut() methods regarding forgotten guards Fixes #139034 This PR improves the documentation for `get_mut()` methods in `Mutex`, `RefCell`, and `RwLock` to clarify their behavior when lock guards are forgotten (e.g., via std::mem::forget). The current documentation for these methods states that a mutable borrow "statically guarantees no locks exist", which is not entirely accurate. While a mutable borrow prevents new locks from being created, it does not clear or detect previously abandoned locks through `forget()`. This can lead to counterintuitive behavior: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=e68cefec12dcd435daf2237c16824ed3 https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=81263ad652c752afd63c903113d3082c https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=311baa4edb3abf82a25c8d7bf21a4a52 r? libs
Diffstat (limited to 'library/std/src/sync')
| -rw-r--r-- | library/std/src/sync/poison/mutex.rs | 6 | ||||
| -rw-r--r-- | library/std/src/sync/poison/rwlock.rs | 4 |
2 files changed, 8 insertions, 2 deletions
diff --git a/library/std/src/sync/poison/mutex.rs b/library/std/src/sync/poison/mutex.rs index 9362c764173..adb74bb6f3d 100644 --- a/library/std/src/sync/poison/mutex.rs +++ b/library/std/src/sync/poison/mutex.rs @@ -582,7 +582,9 @@ impl<T: ?Sized> Mutex<T> { /// Returns a mutable reference to the underlying data. /// /// Since this call borrows the `Mutex` mutably, no actual locking needs to - /// take place -- the mutable borrow statically guarantees no locks exist. + /// take place -- the mutable borrow statically guarantees no new locks can be acquired + /// while this reference exists. Note that this method does not clear any previous abandoned locks + /// (e.g., via [`forget()`] on a [`MutexGuard`]). /// /// # Errors /// @@ -599,6 +601,8 @@ impl<T: ?Sized> Mutex<T> { /// *mutex.get_mut().unwrap() = 10; /// assert_eq!(*mutex.lock().unwrap(), 10); /// ``` + /// + /// [`forget()`]: mem::forget #[stable(feature = "mutex_get_mut", since = "1.6.0")] pub fn get_mut(&mut self) -> LockResult<&mut T> { let data = self.data.get_mut(); diff --git a/library/std/src/sync/poison/rwlock.rs b/library/std/src/sync/poison/rwlock.rs index f9d9321f5f2..a2abd4f692e 100644 --- a/library/std/src/sync/poison/rwlock.rs +++ b/library/std/src/sync/poison/rwlock.rs @@ -608,7 +608,9 @@ impl<T: ?Sized> RwLock<T> { /// Returns a mutable reference to the underlying data. /// /// Since this call borrows the `RwLock` mutably, no actual locking needs to - /// take place -- the mutable borrow statically guarantees no locks exist. + /// take place -- the mutable borrow statically guarantees no new locks can be acquired + /// while this reference exists. Note that this method does not clear any previously abandoned locks + /// (e.g., via [`forget()`] on a [`RwLockReadGuard`] or [`RwLockWriteGuard`]). /// /// # Errors /// |