HeapHammer

HeapHammer v1.2.1

Deterministic Minecraft server stress testing and retained-memory regression detection.

Highlights & Changes

HeapHammer 1.2.1 is a bugfix release on top of 1.2.0 that eliminates a cross-session race in crash-recovery journal persistence.

Fixes

• Stale queued persist could resurrect a deleted journal (CrashRecoveryJournal). Async journal writes are serialized per session by a generation counter, but the guard was per-instance: a write queued by a previous session could still execute after a new session's recoverIfInterrupted()/recordFinish() had already deleted active_run_journal.json, silently recreating it. The next boot would then see a phantom interrupted run. Persist tasks now carry a global monotonic sequence taken at enqueue time, and the staleness check plus write run under a per-path lock shared by all journal instances; recordStart() and recordFinish() publish a floor sequence for the path, so any write enqueued before a lifecycle boundary is dropped. Includes a deterministic regression test that reproduces the interleaving.

Compatibility

No behavior or API changes beyond the journal ordering fix. All workload flags, diagnostics, and fixtures from 1.2.0 are unchanged. Safe upgrade for every supported target: Fabric 1.14.4–1.21.1, Forge 1.7.10/1.12.2/1.16.5/1.18.2/1.20.1, NeoForge 1.21.1.

Full Release Notes & Checksums: https://github.com/DurdeuVlad/heaphammer/releases/tag/v1.2.1