# Changelog ## Unreleased - ## 1.19.0 - Use `portable-atomic` instead of `atomic-polyfill`, [#251](https://github.com/matklad/once_cell/pull/251). ## 1.18.0 - `MSRV` is updated to 1.60.0 to take advantage of `dep:` syntax for cargo features, removing "implementation details" from publicly visible surface. ## 1.17.2 - Avoid unnecessary synchronization in `Lazy::{force,deref}_mut()`, [#231](https://github.com/matklad/once_cell/pull/231). ## 1.17.1 - Make `OnceRef` implementation compliant with [strict provenance](https://github.com/rust-lang/rust/issues/95228). ## 1.17.0 - Add `race::OnceRef` for storing a `&'a T`. ## 1.16.0 - Add `no_std` implementation based on `critical-section`, [#195](https://github.com/matklad/once_cell/pull/195). - Deprecate `atomic-polyfill` feature (use the new `critical-section` instead) ## 1.15.0 - Increase minimal supported Rust version to 1.56.0. - Implement `UnwindSafe` even if the `std` feature is disabled. ## 1.14.0 - Add extension to `unsync` and `sync` `Lazy` mut API: - `force_mut` - `get_mut` ## 1.13.1 - Make implementation compliant with [strict provenance](https://github.com/rust-lang/rust/issues/95228). - Upgrade `atomic-polyfill` to `1.0` ## 1.13.0 - Add `Lazy::get`, similar to `OnceCell::get`. ## 1.12.1 - Remove incorrect `debug_assert`. ## 1.12.0 - Add `OnceCell::wait`, a blocking variant of `get`. ## 1.11.0 - Add `OnceCell::with_value` to create initialized `OnceCell` in `const` context. - Improve `Clone` implementation for `OnceCell`. - Rewrite `parking_lot` version on top of `parking_lot_core`, for even smaller cells! ## 1.10.0 - upgrade `parking_lot` to `0.12.0` (note that this bumps MSRV with `parking_lot` feature enabled to `1.49.0`). ## 1.9.0 - Added an `atomic-polyfill` optional dependency to compile `race` on platforms without atomics ## 1.8.0 - Add `try_insert` API -- a version of `set` that returns a reference. ## 1.7.2 - Improve code size when using parking_lot feature. ## 1.7.1 - Fix `race::OnceBox<T>` to also impl `Default` even if `T` doesn't impl `Default`. ## 1.7.0 - Hide the `race` module behind (default) `race` feature. Turns out that adding `race` by default was a breaking change on some platforms without atomics. In this release, we make the module opt-out. Technically, this is a breaking change for those who use `race` with `no_default_features`. Given that the `race` module itself only several days old, the breakage is deemed acceptable. ## 1.6.0 - Add `Lazy::into_value` - Stabilize `once_cell::race` module for "first one wins" no_std-compatible initialization flavor. - Migrate from deprecated `compare_and_swap` to `compare_exchange`. ## 1.5.2 - `OnceBox` API uses `Box<T>`. This a breaking change to unstable API. ## 1.5.1 - MSRV is increased to `1.36.0`. - document `once_cell::race` module. - introduce `alloc` feature for `OnceBox`. - fix `OnceBox::set`. ## 1.5.0 - add new `once_cell::race` module for "first one wins" no_std-compatible initialization flavor. The API is provisional, subject to change and is gated by the `unstable` cargo feature. ## 1.4.1 - upgrade `parking_lot` to `0.11.0` - make `sync::OnceCell<T>` pass https://doc.rust-lang.org/nomicon/dropck.html#an-escape-hatch[dropck] with `parking_lot` feature enabled. This fixes a (minor) semver-incompatible changed introduced in `1.4.0` ## 1.4.0 - upgrade `parking_lot` to `0.10` (note that this bumps MSRV with `parking_lot` feature enabled to `1.36.0`). - add `OnceCell::take`. - upgrade crossbeam utils (private dependency) to `0.7`. ## 1.3.1 - remove unnecessary `F: fmt::Debug` bound from `impl fmt::Debug for Lazy<T, F>`. ## 1.3.0 - `Lazy<T>` now implements `DerefMut`. - update implementation according to the latest changes in `std`. ## 1.2.0 - add `sync::OnceCell::get_unchecked`. ## 1.1.0 - implement `Default` for `Lazy`: it creates an empty `Lazy<T>` which is initialized with `T::default` on first access. - add `OnceCell::get_mut`. ## 1.0.2 - actually add `#![no_std]` attribute if std feature is not enabled. ## 1.0.1 - fix unsoundness in `Lazy<T>` if the initializing function panics. Thanks [@xfix](https://github.com/xfix)! - implement `RefUnwindSafe` for `Lazy`. - share more code between `std` and `parking_lot` implementations. - add F.A.Q section to the docs. ## 1.0.0 - remove `parking_lot` from the list of default features. - add `std` default feature. Without `std`, only `unsync` module is supported. - implement `Eq` for `OnceCell`. - fix wrong `Sync` bound on `sync::Lazy`. - run the whole test suite with miri. ## 0.2.7 - New implementation of `sync::OnceCell` if `parking_lot` feature is disabled. It now employs a hand-rolled variant of `std::sync::Once`. - `sync::OnceCell::get_or_try_init` works without `parking_lot` as well! - document the effects of `parking_lot` feature: same performance but smaller types. ## 0.2.6 - Updated `Lazy`'s `Deref` impl to requires only `FnOnce` instead of `Fn` ## 0.2.5 - `Lazy` requires only `FnOnce` instead of `Fn` ## 0.2.4 - nicer `fmt::Debug` implementation ## 0.2.3 - update `parking_lot` to `0.9.0` - fix stacked borrows violation in `unsync::OnceCell::get` - implement `Clone` for `sync::OnceCell<T> where T: Clone` ## 0.2.2 - add `OnceCell::into_inner` which consumes a cell and returns an option ## 0.2.1 - implement `sync::OnceCell::get_or_try_init` if `parking_lot` feature is enabled - switch internal `unsafe` implementation of `sync::OnceCell` from `Once` to `Mutex` - `sync::OnceCell::get_or_init` is twice as fast if cell is already initialized - implement `std::panic::RefUnwindSafe` and `std::panic::UnwindSafe` for `OnceCell` - better document behavior around panics ## 0.2.0 - MSRV is now 1.31.1 - `Lazy::new` and `OnceCell::new` are now const-fns - `unsync_lazy` and `sync_lazy` macros are removed ## 0.1.8 - update crossbeam-utils to 0.6 - enable bors-ng ## 0.1.7 - cells implement `PartialEq` and `From` - MSRV is down to 1.24.1 - update `parking_lot` to `0.7.1` ## 0.1.6 - `unsync::OnceCell<T>` is `Clone` if `T` is `Clone`. ## 0.1.5 - No changelog until this point :(