OpenClaw Test Heap Leaks

Use this skill for test-memory investigations. Do not guess from RSS alone when heap snapshots are available. Treat snapshot-name deltas as triage evidence, not proof, until retainers or dominators support the call.

For runtime fixes (e.g., closure leaks in long-running services like the gateway), see Validating runtime fixes below — that uses a dedicated harness, not the test-parallel snapshot machinery.

Workflow

1. Reproduce the failing shape first.

   • Match the real entrypoint if possible. For Linux CI-style unit failures, start with:
   • pnpm canvas:a2ui:bundle && OPENCLAW_TEST_MEMORY_TRACE=1 OPENCLAW_TEST_HEAPSNAPSHOT_INTERVAL_MS=60000 OPENCLAW_TEST_HEAPSNAPSHOT_DIR=.tmp/heapsnap OPENCLAW_TEST_WORKERS=2 OPENCLAW_TEST_MAX_OLD_SPACE_SIZE_MB=6144 pnpm test
   • Keep OPENCLAW_TEST_MEMORY_TRACE=1 enabled so the wrapper prints per-file RSS summaries alongside the snapshots.
   • If the report is about a specific shard or worker budget, preserve that shape.
   • Before you analyze snapshots, identify the real lane names from [test-parallel] start ... lines or pnpm test --plan. Do not assume a single unit-fast lane; local plans often split into unit-fast-batch-*.

2. Wait for repeated snapshots before concluding anything.

   • Take at least two intervals from the same lane.
   • Compare snapshots from the same PID inside the real lane directory such as .tmp/heapsnap/unit-fast-batch-2/.
   • Use .agents/skills/openclaw-test-heap-leaks/scripts/heapsnapshot-delta.mjs to compare either two files directly or the earliest/latest pair per PID in one lane directory.
   • If the helper suggests transformed-module retention, confirm the top entries in DevTools retainers/dominators before calling it solved.

3. Classify the growth before choosing a fix.

   • If growth is dominated by Vite/Vitest transformed source strings, Module, system / Context, bytecode, descriptor arrays, or property maps, treat it as likely retained module graph growth in long-lived workers.
   • If growth is dominated by app objects, caches, buffers, server handles, timers, mock state, sqlite state, or similar runtime objects, treat it as a likely cleanup or lifecycle leak.
   • If the names are ambiguous, stop short of a confident label and inspect retainers/dominators in DevTools for the top deltas.

4. Fix the right layer.

   • For likely retained transformed-module growth in shared workers:
   • Prefer timing and hotspot-driven scheduling fixes first. Check whether the file is already represented in test/fixtures/test-timings.unit.json and whether scripts/test-update-memory-hotspots.mjs should refresh the measured hotspot manifest before hand-editing behavior overrides.
   • Move hotspot files out of the real shared lane by updating test/fixtures/test-parallel.behavior.json only when timing-driven peeling is insufficient.
   • Prefer singletonIsolated for files that are safe alone but inflate shared worker heaps.
   • If the file should already have been peeled out by timings but is absent from test/fixtures/test-timings.unit.json, call that out explicitly. Missing timings are a scheduling blind spot.
   • For real leaks:
   • Patch the implicated test or runtime cleanup path.
   • Look for missing afterEach/afterAll, module-reset gaps, retained global state, unreleased DB handles, or listeners/timers that survive the file.

5. Verify with the most direct proof.

   • Re-run the targeted lane or file with heap snapshots enabled if the suite still finishes in reasonable time.
   • If snapshot overhead pushes tests over Vitest timeouts, fall back to the same lane without snapshots and confirm the RSS trend or OOM is reduced.
   • For wrapper-only changes, at minimum verify the expected lanes start and the snapshot files are written.

Heuristics

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