Releases · al8n/wg

First stable release. Significant breaking changes from 0.9.x — see Migration
from 0.9 below before upgrading.

The crate now commits to Semantic Versioning: breaking
changes to the public API or a bump of the declared MSRV will require a major
version bump.

done() now returns the remaining count, not the previous value. In
0.9.x, future::WaitGroup::done() / no_std::WaitGroup::done() returned the
counter value before the decrement, which contradicted the documented
behaviour. It now consistently returns the count after decrementing. The
blocking WaitGroup was already correct.
waitings() renamed to remaining() on all variants. The new name
reads naturally (if wg.remaining() > 0 { … }) and is consistent across
variants.
Old no_std module replaced by spin. The lock-free, atomic-counter
variant now lives at wg::spin::WaitGroup. In no_std builds,
wg::WaitGroup is a re-export of wg::spin::WaitGroup (backward-compatible
for no_std users).
future::AsyncWaitGroup renamed to future::WaitGroup. Use the
module-qualified name: wg::future::WaitGroup.
The alloc feature no longer pulls in crossbeam-utils; the spin backoff is
now inlined into the crate.

Busy-loop in future::WaitGroup::poll. The previous Pending branch
called wake_by_ref() before returning Pending, causing the executor to
re-poll the future continuously and burn 100% CPU until done() reached
zero. The waker is now only registered once (via the listener) and the
future properly yields.
Wrong return value from done() (see breaking changes above).
std::sync::Mutex poisoning no longer panics. The blocking WaitGroup
now recovers the guard on poisoning via PoisonError::into_inner — a
poisoned counter is not a memory-safety concern, and cascading panics
across every thread touching the group were an over-reaction.
Redundant notify(usize::MAX) on every done(). The async variant now
only notifies waiters when the counter actually reaches zero, instead of
on every decrement.
crossbeam_utils::Backoff::new() was being reset inside the wait loop,
so it never escalated past its first spin budget. Replaced with an inline
adaptive backoff that spins and — on std — yields the OS thread once the
spin budget is exhausted.
Silent over-done no longer triggers the misleading assert_eq!(x, 0).
Calling done() on a zero counter remains a silent no-op returning 0.
The required-features = ["tokio"] on tests/future.rs pointed at a
non-existent feature, so the integration test never ran in CI. Fixed to
required-features = ["future"], and the CI job now exercises it.

Memory ordering tightened: add uses Release, done uses AcqRel/
Acquire, remaining / wait loads use Acquire. The previous SeqCst
everywhere was unnecessarily strong — Release/Acquire provides the
required happens-before edges for this structure.
#![forbid(unsafe_code)] is now enforced at the crate level.

wg::spin::WaitGroup — a lock-free, atomic-counter WaitGroup available on
both std and no_std. Uses an inline adaptive backoff that yields the OS
thread on std and spins on pure no_std.
Dedicated integration tests for each variant.
Compile-time Send + Sync assertions for all three variants.
Declared MSRV (rust-version = "1.76.0", driven by parking_lot and
triomphe floor requirements).

Replace wg::AsyncWaitGroup with wg::future::WaitGroup.
Replace .waitings() with .remaining().
If you relied on done() returning the pre-decrement value on the async /
no_std variants, adjust your code — it now returns the post-decrement value,
matching the blocking variant and the documented contract.
required-features = ["tokio"] in consumer code should be
required-features = ["future"].

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