Changelog

Unreleased

1.19.0

  • Use portable-atomic instead of atomic-polyfill, #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.

1.17.1

1.17.0

  • Add race::OnceRef for storing a &'a T.

1.16.0

  • Add no_std implementation based on critical-section, #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

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

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!
  • 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 :(