Tests: Add tooling / skill for detecting and fixing memory leaks in tests (#50654)

* Tests: add periodic heap snapshot tooling

* Skills: add test heap leak workflow

* Apply suggestion from @greptile-apps[bot]

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

* Update scripts/test-parallel.mjs

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

---------

Co-authored-by: Vincent Koc <vincentkoc@ieee.org>
Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

.agents/skills/openclaw-test-heap-leaks/SKILL.md

@@ -0,0 +1,71 @@
+---
+name: openclaw-test-heap-leaks
+description: Investigate `pnpm test` memory growth, Vitest worker OOMs, and suspicious RSS increases in OpenClaw using the `scripts/test-parallel.mjs` heap snapshot tooling. Use when Codex needs to reproduce test-lane memory growth, collect repeated `.heapsnapshot` files, compare snapshots from the same worker PID, distinguish transformed-module retention from real data leaks, and fix or reduce the impact by patching cleanup logic or isolating hotspot tests.
+---
+
+# OpenClaw Test Heap Leaks
+
+Use this skill for test-memory investigations. Do not guess from RSS alone when heap snapshots are available.
+
+## 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.
+
+2. Wait for repeated snapshots before concluding anything.
+   - Take at least two intervals from the same lane.
+   - Compare snapshots from the same PID inside one lane directory such as `.tmp/heapsnap/unit-fast/`.
+   - Use `scripts/heapsnapshot-delta.mjs` to compare either two files directly or the earliest/latest pair per PID in one lane directory.
+
+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 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.
+
+4. Fix the right layer.
+   - For retained transformed-module growth in shared workers:
+   - Move hotspot files out of `unit-fast` by updating `test/fixtures/test-parallel.behavior.json`.
+   - 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
+
+- Do not call everything a leak. In this repo, large `unit-fast` growth can be a worker-lifetime problem rather than an application object leak.
+- `scripts/test-parallel.mjs` and `scripts/test-parallel-memory.mjs` are the primary control points for wrapper diagnostics.
+- The lane names printed by `[test-parallel] start ...` and `[test-parallel][mem] summary ...` tell you where to focus.
+- When one or two files account for most of the delta and they are missing from timings, reducing impact by isolating them is usually the first pragmatic fix.
+- When the same retained object families grow across multiple intervals in the same worker PID, trust the snapshots over intuition.
+
+## Snapshot Comparison
+
+- Direct comparison:
+  - `node .agents/skills/openclaw-test-heap-leaks/scripts/heapsnapshot-delta.mjs before.heapsnapshot after.heapsnapshot`
+- Auto-select earliest/latest snapshots per PID within one lane:
+  - `node .agents/skills/openclaw-test-heap-leaks/scripts/heapsnapshot-delta.mjs --lane-dir .tmp/heapsnap/unit-fast`
+- Useful flags:
+  - `--top 40`
+  - `--min-kb 32`
+  - `--pid 16133`
+
+Read the top positive deltas first. Large positive growth in module-transform artifacts suggests lane isolation; large positive growth in runtime objects suggests a real leak.
+
+## Output Expectations
+
+When using this skill, report:
+
+- The exact reproduce command.
+- Which lane and PID were compared.
+- The dominant retained object families from the snapshot delta.
+- Whether the issue is a real leak or shared-worker retained module growth.
+- The concrete fix or impact-reduction patch.
+- What you verified, and what snapshot overhead prevented you from verifying.

.agents/skills/openclaw-test-heap-leaks/agents/openai.yaml

@@ -0,0 +1,4 @@
+interface:
+  display_name: "Test Heap Leaks"
+  short_description: "Investigate test OOMs with heap snapshots"
+  default_prompt: "Use $openclaw-test-heap-leaks to investigate test memory growth with heap snapshots and reduce its impact."

.agents/skills/openclaw-test-heap-leaks/scripts/heapsnapshot-delta.mjs

@@ -0,0 +1,265 @@
+#!/usr/bin/env node
+
+import fs from "node:fs";
+import path from "node:path";
+
+function printUsage() {
+  console.error(
+    "Usage: node heapsnapshot-delta.mjs <before.heapsnapshot> <after.heapsnapshot> [--top N] [--min-kb N]",
+  );
+  console.error(
+    "   or: node heapsnapshot-delta.mjs --lane-dir <dir> [--pid PID] [--top N] [--min-kb N]",
+  );
+}
+
+function fail(message) {
+  console.error(message);
+  process.exit(1);
+}
+
+function parseArgs(argv) {
+  const options = {
+    top: 30,
+    minKb: 64,
+    laneDir: null,
+    pid: null,
+    files: [],
+  };
+
+  for (let index = 0; index < argv.length; index += 1) {
+    const arg = argv[index];
+    if (arg === "--top") {
+      options.top = Number.parseInt(argv[index + 1] ?? "", 10);
+      index += 1;
+      continue;
+    }
+    if (arg === "--min-kb") {
+      options.minKb = Number.parseInt(argv[index + 1] ?? "", 10);
+      index += 1;
+      continue;
+    }
+    if (arg === "--lane-dir") {
+      options.laneDir = argv[index + 1] ?? null;
+      index += 1;
+      continue;
+    }
+    if (arg === "--pid") {
+      options.pid = Number.parseInt(argv[index + 1] ?? "", 10);
+      index += 1;
+      continue;
+    }
+    options.files.push(arg);
+  }
+
+  if (!Number.isFinite(options.top) || options.top <= 0) {
+    fail("--top must be a positive integer");
+  }
+  if (!Number.isFinite(options.minKb) || options.minKb < 0) {
+    fail("--min-kb must be a non-negative integer");
+  }
+  if (options.pid !== null && (!Number.isInteger(options.pid) || options.pid <= 0)) {
+    fail("--pid must be a positive integer");
+  }
+
+  return options;
+}
+
+function parseHeapFilename(filePath) {
+  const base = path.basename(filePath);
+  const match = base.match(
+    /^Heap\.(?<stamp>\d{8}\.\d{6})\.(?<pid>\d+)\.0\.(?<seq>\d+)\.heapsnapshot$/u,
+  );
+  if (!match?.groups) {
+    return null;
+  }
+  return {
+    filePath,
+    pid: Number.parseInt(match.groups.pid, 10),
+    stamp: match.groups.stamp,
+    sequence: Number.parseInt(match.groups.seq, 10),
+  };
+}
+
+function resolvePair(options) {
+  if (options.laneDir) {
+    const entries = fs
+      .readdirSync(options.laneDir)
+      .map((name) => parseHeapFilename(path.join(options.laneDir, name)))
+      .filter((entry) => entry !== null)
+      .filter((entry) => options.pid === null || entry.pid === options.pid)
+      .toSorted((left, right) => {
+        if (left.pid !== right.pid) {
+          return left.pid - right.pid;
+        }
+        if (left.stamp !== right.stamp) {
+          return left.stamp.localeCompare(right.stamp);
+        }
+        return left.sequence - right.sequence;
+      });
+
+    if (entries.length === 0) {
+      fail(`No matching heap snapshots found in ${options.laneDir}`);
+    }
+
+    const groups = new Map();
+    for (const entry of entries) {
+      const group = groups.get(entry.pid) ?? [];
+      group.push(entry);
+      groups.set(entry.pid, group);
+    }
+
+    const candidates = Array.from(groups.values())
+      .map((group) => ({
+        pid: group[0].pid,
+        before: group[0],
+        after: group.at(-1),
+        count: group.length,
+      }))
+      .filter((entry) => entry.count >= 2);
+
+    if (candidates.length === 0) {
+      fail(`Need at least two snapshots for one PID in ${options.laneDir}`);
+    }
+
+    const chosen =
+      options.pid !== null
+        ? (candidates.find((entry) => entry.pid === options.pid) ?? null)
+        : candidates.toSorted((left, right) => right.count - left.count || left.pid - right.pid)[0];
+
+    if (!chosen) {
+      fail(`No PID with at least two snapshots matched in ${options.laneDir}`);
+    }
+
+    return {
+      before: chosen.before.filePath,
+      after: chosen.after.filePath,
+      pid: chosen.pid,
+      snapshotCount: chosen.count,
+    };
+  }
+
+  if (options.files.length !== 2) {
+    printUsage();
+    process.exit(1);
+  }
+
+  return {
+    before: options.files[0],
+    after: options.files[1],
+    pid: null,
+    snapshotCount: 2,
+  };
+}
+
+function loadSummary(filePath) {
+  const data = JSON.parse(fs.readFileSync(filePath, "utf8"));
+  const meta = data.snapshot?.meta;
+  if (!meta) {
+    fail(`Invalid heap snapshot: ${filePath}`);
+  }
+
+  const nodeFieldCount = meta.node_fields.length;
+  const typeNames = meta.node_types[0];
+  const strings = data.strings;
+  const typeIndex = meta.node_fields.indexOf("type");
+  const nameIndex = meta.node_fields.indexOf("name");
+  const selfSizeIndex = meta.node_fields.indexOf("self_size");
+
+  const summary = new Map();
+  for (let offset = 0; offset < data.nodes.length; offset += nodeFieldCount) {
+    const type = typeNames[data.nodes[offset + typeIndex]];
+    const name = strings[data.nodes[offset + nameIndex]];
+    const selfSize = data.nodes[offset + selfSizeIndex];
+    const key = `${type}\t${name}`;
+    const current = summary.get(key) ?? {
+      type,
+      name,
+      selfSize: 0,
+      count: 0,
+    };
+    current.selfSize += selfSize;
+    current.count += 1;
+    summary.set(key, current);
+  }
+  return {
+    nodeCount: data.snapshot.node_count,
+    summary,
+  };
+}
+
+function formatBytes(bytes) {
+  if (Math.abs(bytes) >= 1024 ** 2) {
+    return `${(bytes / 1024 ** 2).toFixed(2)} MiB`;
+  }
+  if (Math.abs(bytes) >= 1024) {
+    return `${(bytes / 1024).toFixed(1)} KiB`;
+  }
+  return `${bytes} B`;
+}
+
+function formatDelta(bytes) {
+  return `${bytes >= 0 ? "+" : "-"}${formatBytes(Math.abs(bytes))}`;
+}
+
+function truncate(text, maxLength) {
+  return text.length <= maxLength ? text : `${text.slice(0, maxLength - 1)}…`;
+}
+
+function main() {
+  const options = parseArgs(process.argv.slice(2));
+  const pair = resolvePair(options);
+  const before = loadSummary(pair.before);
+  const after = loadSummary(pair.after);
+  const minBytes = options.minKb * 1024;
+
+  const rows = [];
+  for (const [key, next] of after.summary) {
+    const previous = before.summary.get(key) ?? { selfSize: 0, count: 0 };
+    const sizeDelta = next.selfSize - previous.selfSize;
+    const countDelta = next.count - previous.count;
+    if (sizeDelta < minBytes) {
+      continue;
+    }
+    rows.push({
+      type: next.type,
+      name: next.name,
+      sizeDelta,
+      countDelta,
+      afterSize: next.selfSize,
+      afterCount: next.count,
+    });
+  }
+
+  rows.sort(
+    (left, right) => right.sizeDelta - left.sizeDelta || right.countDelta - left.countDelta,
+  );
+
+  console.log(`before: ${pair.before}`);
+  console.log(`after:  ${pair.after}`);
+  if (pair.pid !== null) {
+    console.log(`pid:    ${pair.pid} (${pair.snapshotCount} snapshots found)`);
+  }
+  console.log(
+    `nodes:   ${before.nodeCount} -> ${after.nodeCount} (${after.nodeCount - before.nodeCount >= 0 ? "+" : ""}${after.nodeCount - before.nodeCount})`,
+  );
+  console.log(`filter:  top=${options.top} min=${options.minKb} KiB`);
+  console.log("");
+
+  if (rows.length === 0) {
+    console.log("No entries exceeded the minimum delta.");
+    return;
+  }
+
+  for (const row of rows.slice(0, options.top)) {
+    console.log(
+      [
+        formatDelta(row.sizeDelta).padStart(11),
+        `count ${row.countDelta >= 0 ? "+" : ""}${row.countDelta}`.padStart(10),
+        row.type.padEnd(16),
+        truncate(row.name || "(empty)", 96),
+      ].join("  "),
+    );
+  }
+}
+
+main();

scripts/test-parallel-memory.mjs

@@ -11,7 +11,7 @@ const ANSI_ESCAPE_PATTERN = new RegExp(
 const COMPLETED_TEST_FILE_LINE_PATTERN =
   /(?<file>(?:src|extensions|test|ui)\/\S+?\.(?:live\.test|e2e\.test|test)\.ts)\s+\(.*\)\s+(?<duration>\d+(?:\.\d+)?)(?<unit>ms|s)\s*$/;
 
-const PS_COLUMNS = ["pid=", "ppid=", "rss="];
+const PS_COLUMNS = ["pid=", "ppid=", "rss=", "comm="];
 
 function parseDurationMs(rawValue, unit) {
   const parsed = Number.parseFloat(rawValue);
@@ -41,7 +41,7 @@ export function parseCompletedTestFileLines(text) {
     .filter((entry) => entry !== null);
 }
 
-export function sampleProcessTreeRssKb(rootPid) {
+export function getProcessTreeRecords(rootPid) {
   if (!Number.isInteger(rootPid) || rootPid <= 0 || process.platform === "win32") {
     return null;
   }
@@ -54,13 +54,13 @@ export function sampleProcessTreeRssKb(rootPid) {
   }
 
   const childPidsByParent = new Map();
-  const rssByPid = new Map();
+  const recordsByPid = new Map();
   for (const line of result.stdout.split(/\r?\n/u)) {
     const trimmed = line.trim();
     if (!trimmed) {
       continue;
     }
-    const [pidRaw, parentRaw, rssRaw] = trimmed.split(/\s+/u);
+    const [pidRaw, parentRaw, rssRaw, commandRaw] = trimmed.split(/\s+/u, 4);
     const pid = Number.parseInt(pidRaw ?? "", 10);
     const parentPid = Number.parseInt(parentRaw ?? "", 10);
     const rssKb = Number.parseInt(rssRaw ?? "", 10);
@@ -70,27 +70,30 @@ export function sampleProcessTreeRssKb(rootPid) {
     const siblings = childPidsByParent.get(parentPid) ?? [];
     siblings.push(pid);
     childPidsByParent.set(parentPid, siblings);
-    rssByPid.set(pid, rssKb);
+    recordsByPid.set(pid, {
+      pid,
+      parentPid,
+      rssKb,
+      command: commandRaw ?? "",
+    });
   }
 
-  if (!rssByPid.has(rootPid)) {
+  if (!recordsByPid.has(rootPid)) {
     return null;
   }
 
-  let rssKb = 0;
-  let processCount = 0;
   const queue = [rootPid];
   const visited = new Set();
+  const records = [];
   while (queue.length > 0) {
     const pid = queue.shift();
     if (pid === undefined || visited.has(pid)) {
       continue;
     }
     visited.add(pid);
-    const currentRssKb = rssByPid.get(pid);
+    const record = recordsByPid.get(pid);
-    if (currentRssKb !== undefined) {
+    if (record) {
-      rssKb += currentRssKb;
+      records.push(record);
-      processCount += 1;
     }
     for (const childPid of childPidsByParent.get(pid) ?? []) {
       if (!visited.has(childPid)) {
@@ -99,5 +102,21 @@ export function sampleProcessTreeRssKb(rootPid) {
     }
   }
 
+  return records;
+}
+
+export function sampleProcessTreeRssKb(rootPid) {
+  const records = getProcessTreeRecords(rootPid);
+  if (!records) {
+    return null;
+  }
+
+  let rssKb = 0;
+  let processCount = 0;
+  for (const record of records) {
+    rssKb += record.rssKb;
+    processCount += 1;
+  }
+
   return { rssKb, processCount };
 }

scripts/test-parallel.mjs

@@ -4,7 +4,11 @@ import os from "node:os";
 import path from "node:path";
 import { channelTestPrefixes } from "../vitest.channel-paths.mjs";
 import { isUnitConfigTestFile } from "../vitest.unit-paths.mjs";
-import { parseCompletedTestFileLines, sampleProcessTreeRssKb } from "./test-parallel-memory.mjs";
+import {
+  getProcessTreeRecords,
+  parseCompletedTestFileLines,
+  sampleProcessTreeRssKb,
+} from "./test-parallel-memory.mjs";
 import {
   appendCapturedOutput,
   hasFatalTestRunOutput,
@@ -725,6 +729,25 @@ const memoryTraceEnabled =
     (rawMemoryTrace !== "0" && rawMemoryTrace !== "false" && isCI));
 const memoryTracePollMs = Math.max(250, parseEnvNumber("OPENCLAW_TEST_MEMORY_TRACE_POLL_MS", 1000));
 const memoryTraceTopCount = Math.max(1, parseEnvNumber("OPENCLAW_TEST_MEMORY_TRACE_TOP_COUNT", 6));
+const heapSnapshotIntervalMs = Math.max(
+  0,
+  parseEnvNumber("OPENCLAW_TEST_HEAPSNAPSHOT_INTERVAL_MS", 0),
+);
+const heapSnapshotMinIntervalMs = 5000;
+const heapSnapshotEnabled =
+  process.platform !== "win32" &&
+  heapSnapshotIntervalMs >= heapSnapshotMinIntervalMs;
+const heapSnapshotEnabled = process.platform !== "win32" && heapSnapshotIntervalMs > 0;
+const heapSnapshotSignal = process.env.OPENCLAW_TEST_HEAPSNAPSHOT_SIGNAL?.trim() || "SIGUSR2";
+const heapSnapshotBaseDir = heapSnapshotEnabled
+  ? path.resolve(
+      process.env.OPENCLAW_TEST_HEAPSNAPSHOT_DIR?.trim() ||
+        path.join(os.tmpdir(), `openclaw-heapsnapshots-${Date.now()}`),
+    )
+  : null;
+const ensureNodeOptionFlag = (nodeOptions, flagPrefix, nextValue) =>
+  nodeOptions.includes(flagPrefix) ? nodeOptions : `${nodeOptions} ${nextValue}`.trim();
+const isNodeLikeProcess = (command) => /(?:^|\/)node(?:$|\.exe$)/iu.test(command);
 
 const runOnce = (entry, extraArgs = []) =>
   new Promise((resolve) => {
@@ -757,23 +780,44 @@ const runOnce = (entry, extraArgs = []) =>
       (acc, flag) => (acc.includes(flag) ? acc : `${acc} ${flag}`.trim()),
       nodeOptions,
     );
-    const heapFlag =
+    const heapSnapshotDir =
+      heapSnapshotBaseDir === null ? null : path.join(heapSnapshotBaseDir, entry.name);
+    let resolvedNodeOptions =
       maxOldSpaceSizeMb && !nextNodeOptions.includes("--max-old-space-size=")
-        ? `--max-old-space-size=${maxOldSpaceSizeMb}`
+        ? `${nextNodeOptions} --max-old-space-size=${maxOldSpaceSizeMb}`.trim()
-        : null;
-    const resolvedNodeOptions = heapFlag
-      ? `${nextNodeOptions} ${heapFlag}`.trim()
         : nextNodeOptions;
+    if (heapSnapshotEnabled && heapSnapshotDir) {
+      try {
+        fs.mkdirSync(heapSnapshotDir, { recursive: true });
+      } catch (err) {
+        console.error(`[test-parallel] failed to create heap snapshot dir ${heapSnapshotDir}: ${String(err)}`);
+        resolve(1);
+        return;
+      }
+      resolvedNodeOptions = ensureNodeOptionFlag(
+        resolvedNodeOptions,
+        "--diagnostic-dir=",
+        `--diagnostic-dir=${heapSnapshotDir}`,
+      );
+      resolvedNodeOptions = ensureNodeOptionFlag(
+        resolvedNodeOptions,
+        "--heapsnapshot-signal=",
+        `--heapsnapshot-signal=${heapSnapshotSignal}`,
+      );
+    }
+    }
     let output = "";
     let fatalSeen = false;
     let childError = null;
     let child;
     let pendingLine = "";
     let memoryPollTimer = null;
+    let heapSnapshotTimer = null;
     const memoryFileRecords = [];
     let initialTreeSample = null;
     let latestTreeSample = null;
     let peakTreeSample = null;
+    let heapSnapshotSequence = 0;
     const updatePeakTreeSample = (sample, reason) => {
       if (!sample) {
         return;
@@ -782,6 +826,35 @@ const runOnce = (entry, extraArgs = []) =>
         peakTreeSample = { ...sample, reason };
       }
     };
+    const triggerHeapSnapshot = (reason) => {
+      if (!heapSnapshotEnabled || !child?.pid || !heapSnapshotDir) {
+        return;
+      }
+      const records = getProcessTreeRecords(child.pid) ?? [];
+      const targetPids = records
+        .filter((record) => record.pid !== process.pid && isNodeLikeProcess(record.command))
+        .map((record) => record.pid);
+      if (targetPids.length === 0) {
+        return;
+      }
+      heapSnapshotSequence += 1;
+      let signaledCount = 0;
+      for (const pid of targetPids) {
+        try {
+          process.kill(pid, heapSnapshotSignal);
+          signaledCount += 1;
+        } catch {
+          // Process likely exited between ps sampling and signal delivery.
+        }
+      }
+      if (signaledCount > 0) {
+        console.log(
+          `[test-parallel][heap] ${entry.name} seq=${String(heapSnapshotSequence)} reason=${reason} signaled=${String(
+            signaledCount,
+          )}/${String(targetPids.length)} dir=${heapSnapshotDir}`,
+        );
+      }
+    };
     const captureTreeSample = (reason) => {
       if (!memoryTraceEnabled || !child?.pid) {
         return null;
@@ -877,6 +950,11 @@ const runOnce = (entry, extraArgs = []) =>
           captureTreeSample("poll");
         }, memoryTracePollMs);
       }
+      if (heapSnapshotEnabled) {
+        heapSnapshotTimer = setInterval(() => {
+          triggerHeapSnapshot("interval");
+        }, heapSnapshotIntervalMs);
+      }
     } catch (err) {
       console.error(`[test-parallel] spawn failed: ${String(err)}`);
       resolve(1);
@@ -905,6 +983,9 @@ const runOnce = (entry, extraArgs = []) =>
       if (memoryPollTimer) {
         clearInterval(memoryPollTimer);
       }
+      if (heapSnapshotTimer) {
+        clearInterval(heapSnapshotTimer);
+      }
       children.delete(child);
       const resolvedCode = resolveTestRunExitCode({ code, signal, output, fatalSeen, childError });
       logMemoryTraceSummary();