vendor/once_cell-1.19.0/CHANGELOG.md - toolchain/rustc - Git at Google

 # 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 :(
	# 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 :(