spin

Added

• lock_api::MappedMutexGuard

Fixed

• Unsoundness in Once::force_into_inner, Once::try_into_inner, and Once::into_inner_unchecked. Thanks to @Poseidon for catching this.

Fixed

• Unsoundness in RwLock's try_upgrade path for the lock_api interface has been fixed. Note that this unsoundness only affects you if all of the following apply:

  • You use RwLock via the lock_api interface specifically
  • You call upgradable_read to create an upgradeable lock guard
  • You call try_upgrade on the upgradeable lock guard

• LazyLock's Sync implementation is now less restrictive

Changed

• Moved to Codeberg

Fixed

• Unsoundness in FairMutex caused by an undue extension of a reference lifetime outside of a critical section. Note that we do not consider this CVE-worthy since there's no clear path to exploiting this and there's no clear reason for the compiler to actually generate code that falls afoul of the issue. If you have found an example of this issue leading to unexpected behaviour in practice, please open an issue.

Added

• lock_api mapped read/write guard for RwLock
• Once::init_from_ref
• rustc-dep-of-std feature, allowing spin to be used as a standard library dependency

Changed

• MSRV is now 1.71
• Lazy is now LazyLock

Fixed

• lock_api feature name for RawRwLockUpgradeDowngrade

Added

• Mutex::try_lock_weak
• RwLock::try_write_weak
• RwLock::try_upgrade_weak

Changed

• Updated MSRV to 1.60
• Use dep: syntax in Cargo.toml
• portable_atomic feature has been renamed to portable-atomic, for consistency.

Fixed

Fixed

• Unsoundness in Once::try_call_once caused by an Err(_) result

Fixed

• Relaxed accidentally restricted Send/Sync bounds for Mutex guards

Fixed

• Relaxed accidentally restricted Send/Sync bounds for RwLock guards

Added

• FairMutex, a new mutex implementation that reduces writer starvation.
• A MSRV policy: Rust 1.38 is currently required

Changed

• The crate's CI now has full MIRI integration, further improving the confidence you can have in the implementation.

Fixed

• Ensured that the crate's abstractions comply with stacked borrows rules.
• Unsoundness in the RwLock that could be triggered via a reader overflow
• Relaxed various Send/Sync bound requirements to make the crate more flexible

Fixed

• Fixed unsoundness in RwLock on reader overflow
• Relaxed Send/Sync bounds for SpinMutex and TicketMutex (doesn't affect Mutex itself)

Added

• Implemented Default for Once
• Once::try_call_once

Fixed

• Fixed bug that caused Once::call_once to incorrectly fail

Changed

• Improved Once performance by reducing the memory footprint of internal state to one byte

Fixed

• Improved performance of Once by relaxing ordering guarantees and removing redundant checks

Added

• Default type parameter on Once for better ergonomics

Changed

• Placed all major API features behind feature flags

Fixed

• A compilation bug with the lock_api feature

Added

• Once::get_unchecked
• RelaxStrategy trait with type parameter on all locks to support switching between relax strategies

Changed

• lock_api1 feature is now named lock_api

Fixed

• Prevented Once leaking the inner value upon drop

Added

• Once::initialized
• Once::get_mut
• Once::try_into_inner
• Once::poll
• RwLock, Mutex and Once now implement From<T>
• Lazy type for lazy initialization
• TicketMutex, an alternative mutex implementation
• std feature flag to enable thread yielding instead of spinning
• Mutex::is_locked/SpinMutex::is_locked/TicketMutex::is_locked
• Barrier

Changed

• Once::wait now spins even if initialization has not yet started
• Guard::leak is now an associated function instead of a method
• Improved the performance of SpinMutex by relaxing unnecessarily conservative ordering requirements

Added

• More dynamic Send/Sync bounds for lock guards
• lock_api compatibility
• Guard::leak methods
• RwLock::reader_count and RwLock::writer_count
• Display implementation for guard types

Changed

• Made Debug impls of lock guards just show the inner type like std