From f8be51862aa51998a0954f53540bdf7d4f002bbd Mon Sep 17 00:00:00 2001 From: Taiki Endo Date: Thu, 30 Jan 2025 23:32:05 +0900 Subject: [PATCH] Move mutex_integer to restriction and improve mutex_{integer,atomic} docs --- clippy_lints/src/mutex_atomic.rs | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/clippy_lints/src/mutex_atomic.rs b/clippy_lints/src/mutex_atomic.rs index 86c084423b71..49fd29d1dd6d 100644 --- a/clippy_lints/src/mutex_atomic.rs +++ b/clippy_lints/src/mutex_atomic.rs @@ -18,11 +18,14 @@ declare_clippy_lint! { /// /// On the other hand, `Mutex`es are, in general, easier to /// verify correctness. An atomic does not behave the same as - /// an equivalent mutex. See [this issue](https://github.com/rust-lang/rust-clippy/issues/4295)'s commentary for more details. + /// an equivalent mutex. See [this issue](https://github.com/rust-lang/rust-clippy/issues/4295)'s + /// commentary for more details. /// /// ### Known problems - /// This lint cannot detect if the mutex is actually used - /// for waiting before a critical section. + /// * This lint cannot detect if the mutex is actually used + /// for waiting before a critical section. + /// * This lint has a false positive that warns without considering the case + /// where `Mutex` is used together with `Condvar`. /// /// ### Example /// ```no_run @@ -48,14 +51,23 @@ declare_clippy_lint! { /// Checks for usage of `Mutex` where `X` is an integral /// type. /// - /// ### Why is this bad? + /// ### Why restrict this? /// Using a mutex just to make access to a plain integer /// sequential is /// shooting flies with cannons. `std::sync::atomic::AtomicUsize` is leaner and faster. /// + /// On the other hand, `Mutex`es are, in general, easier to + /// verify correctness. An atomic does not behave the same as + /// an equivalent mutex. See [this issue](https://github.com/rust-lang/rust-clippy/issues/4295)'s + /// commentary for more details. + /// /// ### Known problems - /// This lint cannot detect if the mutex is actually used - /// for waiting before a critical section. + /// * This lint cannot detect if the mutex is actually used + /// for waiting before a critical section. + /// * This lint has a false positive that warns without considering the case + /// where `Mutex` is used together with `Condvar`. + /// * This lint suggest using `AtomicU64` instead of `Mutex`, but + /// `AtomicU64` is not available on some 32-bit platforms. /// /// ### Example /// ```no_run @@ -70,7 +82,7 @@ declare_clippy_lint! { /// ``` #[clippy::version = "pre 1.29.0"] pub MUTEX_INTEGER, - nursery, + restriction, "using a mutex for an integer type" } @@ -108,7 +120,7 @@ fn get_atomic_name(ty: Ty<'_>) -> Option<&'static str> { UintTy::U32 => Some("AtomicU32"), UintTy::U64 => Some("AtomicU64"), UintTy::Usize => Some("AtomicUsize"), - // There's no `AtomicU128`. + // `AtomicU128` is unstable and only available on a few platforms: https://github.com/rust-lang/rust/issues/99069 UintTy::U128 => None, } }, @@ -119,7 +131,7 @@ fn get_atomic_name(ty: Ty<'_>) -> Option<&'static str> { IntTy::I32 => Some("AtomicI32"), IntTy::I64 => Some("AtomicI64"), IntTy::Isize => Some("AtomicIsize"), - // There's no `AtomicI128`. + // `AtomicU128` is unstable and only available on a few platforms: https://github.com/rust-lang/rust/issues/99069 IntTy::I128 => None, } },