• Fixed a bug where re-inserting an expired entry could cause it to lose its expiration time and remain in the cache indefinitely when using a custom Expiry policy with per-entry expiration. (#582 by @jiangzhe, #581 by @atrocities, reported in #575):
  • This occurred when an entry that had expired but not yet been evicted was re-inserted, and expire_after_update returned None. This primarily affected users who only override expire_after_create, since the default expire_after_update returns duration_until_expiry, which is None for expired entries.
  • This bug was introduced by the changes in v0.12.13 (#549 and #564).
  • Subtle behavior change:
    • Before this fix, re-inserting an expired entry was treated as an update, so Expiry::expire_after_update was called.
    • After this fix, re-inserting an expired entry is treated as a creation, so Expiry::expire_after_create is called instead.
    • This may change the expiration time of re-inserted entries, depending on your Expiry trait implementation.
• Fixed flaky tests cht::segment::tests::drop_many_values and drop_many_values_concurrent that were failing on high-core-count machines (#586):
  • These tests were using a CPU-dependent segment count, causing inconsistent bucket array shrinking behavior of the internal segmented hash map across different machines.
  • Changed these tests to use a fixed segment count (4) for consistent results.

• Disabled flaky GC-dependent tests by default using run_flaky_tests cfg (#584):
  • These tests rely on epoch-based garbage collection (crossbeam-epoch) timing that is not guaranteed, causing intermittent failures.
  • Fixed #539 and #580.
  • To run these tests, set RUSTFLAGS='--cfg run_flaky_tests'.

• Fixed a race condition in the and_compute_with method in the future::Cache. (#574 by @Squadrick):
  • When multiple calls are made concurrently for the same key, the f closure may read a stale value, causing the first update to be lost when it is overwritten by a later one.

• Use dep: keyword in the crate features. (#577 by @alexanderkjall).

• Fixed/mitigated use-after-free issues in the hierarchical timer wheels when Expiry returns None (Issue #565, reported by @sharksforarms).
  • Fixed a bug that caused freed timer nodes to remain in the timer wheels in some edge cases (#566 by @powergee).
  • The mitigation added to v0.12.12 was enhanced by atomically reading the expiration state to prevent rare race conditions that could cause use-after-free issues (#570).
• Fixed Expiry::expire_after_update not clearing expiration time for expired entries (future::Cache: #549, by @singulared, sync::Cache: #564).

Bumped the minimum supported Rust version (MSRV) to 1.71.1, released on August 3, 2023 (#555).

• Fixed use-after-free panic in the hierarchical timer wheels when Expiry returns None (#548, by @awarus).
• Fixed a subtle undefined behavior (UB) in the internal deque::move_to_back method (found by Miri) (#553).

• impl Expiry for some types (#519, by @koushiro).

• Removed several unneeded files from the published package (#541, by @weiznich).
• Removed the once_cell crate from the dependencies (#520, by @Expyron).
• Removed the rustc_version crate from the dev-dependencies (#554).