chore: merge upstream v12.3.8 + keep local fixes

Upstream:
- 12.3.8: detect PID reuse in worker start-guard (#2082) — fixes
  docker container restart where new worker inherits the old PID
  and kill(pid, 0) falsely reports the old instance alive. Uses
  /proc/<pid>/stat starttime on Linux and `ps -p <pid> -o lstart=`
  on macOS/POSIX as an opaque process-start identity token.

Low impact for macOS Desktop users but worth carrying.

Local fixes preserved: env-sanitizer PATH extension, SessionStore
stale session reset. Both verified in built worker-service.cjs.
Worker restarted to v12.3.8.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -10,7 +10,7 @@
   "plugins": [
     {
       "name": "claude-mem",
-      "version": "12.3.7",
+      "version": "12.3.8",
       "source": "./plugin",
       "description": "Persistent memory system for Claude Code - context compression across sessions"
     }

.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem",
-  "version": "12.3.7",
+  "version": "12.3.8",
   "description": "Memory compression system for Claude Code - persist context across sessions",
   "author": {
     "name": "Alex Newman"

.codex-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem",
-  "version": "12.3.7",
+  "version": "12.3.8",
   "description": "Memory compression system for Claude Code - persist context across sessions",
   "author": {
     "name": "Alex Newman",

CHANGELOG.md

@@ -4,6 +4,31 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [12.3.8] - 2026-04-21
+
+## 🔧 Fix
+
+**Detect PID reuse in the worker start-guard so containers can restart cleanly.** (#2082)
+
+The `kill(pid, 0)` liveness check false-positived when the worker's PID file outlived its PID namespace — most commonly after `docker stop` / `docker start` with a bind-mounted `~/.claude-mem`. The new worker would boot as the same low PID (often 11) as the old one, `kill(0)` would report "alive," and the worker would refuse to start *against its own prior incarnation*. Symptom: container appeared to start, immediately exited cleanly with no user-visible error, worker never came up.
+
+### What changed
+
+- Capture an opaque **process-start identity token** alongside the PID and verify identity, not just liveness:
+  - **Linux**: `/proc/<pid>/stat` field 22 (starttime in jiffies) — cheap, no exec, same signal `pgrep`/`systemd` use.
+  - **macOS / POSIX**: `ps -p <pid> -o lstart=` with `LC_ALL=C` pinned so the emitted timestamp is locale-independent across environments.
+  - **Windows**: unchanged — falls back to liveness-only. The PID-reuse scenario doesn't affect Windows deployments the way containers do.
+- `verifyPidFileOwnership` emits a DEBUG log when liveness passes but the token mismatches, so the "PID reused" case is distinguishable from "process dead" in production logs.
+- PID files written by older versions are token-less; `verifyPidFileOwnership` falls back to the existing liveness-only behavior for backwards compatibility. **No migration required.**
+
+### Surface
+
+Shared helpers (`PidInfo`, `captureProcessStartToken`, `verifyPidFileOwnership`) live in `src/supervisor/process-registry.ts` and are re-exported from `ProcessManager.ts` to preserve the existing public surface. Both entry points updated: `worker-service.ts` GUARD 1 and `supervisor/index.ts` `validateWorkerPidFile`.
+
+### Tests
+
++14 new tests covering token capture, ownership verification, backwards compatibility for tokenless PID files, and the container-restart regression scenario. Zero regressions.
+
 ## [12.3.7] - 2026-04-20
 
 ## What's Changed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem",
-  "version": "12.3.7",
+  "version": "12.3.8",
   "description": "Memory compression system for Claude Code - persist context across sessions",
   "keywords": [
     "claude",

plugin/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem",
-  "version": "12.3.7",
+  "version": "12.3.8",
   "description": "Persistent memory system for Claude Code - seamlessly preserve context across sessions",
   "author": {
     "name": "Alex Newman"

plugin/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-mem-plugin",
-  "version": "12.3.7",
+  "version": "12.3.8",
   "private": true,
   "description": "Runtime dependencies for claude-mem bundled hooks",
   "type": "module",

src/services/infrastructure/ProcessManager.ts

@@ -185,18 +185,26 @@ function resolveWorkerRuntimePathUncached(options: RuntimeResolverOptions): stri
   return lookupInPath('bun', platform);
 }
 
-export interface PidInfo {
-  pid: number;
-  port: number;
-  startedAt: string;
-}
+import {
+  captureProcessStartToken,
+  verifyPidFileOwnership,
+  type PidInfo
+} from '../../supervisor/process-registry.js';
+export { captureProcessStartToken, verifyPidFileOwnership, type PidInfo };
 
 /**
- * Write PID info to the standard PID file location
+ * Write PID info to the standard PID file location.
+ *
+ * Automatically captures a process-start token for `info.pid` if the caller
+ * didn't supply one. The token lets future readers detect PID reuse across
+ * reboots/container restarts — see captureProcessStartToken in
+ * supervisor/process-registry.ts.
  */
 export function writePidFile(info: PidInfo): void {
   mkdirSync(DATA_DIR, { recursive: true });
-  writeFileSync(PID_FILE, JSON.stringify(info, null, 2));
+  const resolvedToken = info.startToken ?? captureProcessStartToken(info.pid);
+  const payload: PidInfo = resolvedToken ? { ...info, startToken: resolvedToken } : info;
+  writeFileSync(PID_FILE, JSON.stringify(payload, null, 2));
 }
 
 /**

src/services/worker-service.ts

@@ -48,7 +48,7 @@ import {
   runOneTimeChromaMigration,
   runOneTimeCwdRemap,
   cleanStalePidFile,
-  isProcessAlive,
+  verifyPidFileOwnership,
   spawnDaemon,
   touchPidFile
 } from './infrastructure/ProcessManager.js';
@@ -1361,10 +1361,13 @@ async function main() {
 
     case '--daemon':
     default: {
-      // GUARD 1: Refuse to start if another worker is already alive (PID check).
-      // Instant check (kill -0) — no HTTP dependency.
+      // GUARD 1: Refuse to start if another worker is already alive.
+      // Verifies PID *identity* (via start-time token) not just liveness, so a
+      // stale PID file pointing at a PID that's since been reused by an
+      // unrelated process (e.g. container restart reusing low PIDs) doesn't
+      // false-positive.
       const existingPidInfo = readPidFile();
-      if (existingPidInfo && isProcessAlive(existingPidInfo.pid)) {
+      if (verifyPidFileOwnership(existingPidInfo)) {
         logger.info('SYSTEM', 'Worker already running (PID alive), refusing to start duplicate', {
           existingPid: existingPidInfo.pid,
           existingPort: existingPidInfo.port,

src/supervisor/index.ts

@@ -2,19 +2,19 @@ import { existsSync, readFileSync, rmSync } from 'fs';
 import { homedir } from 'os';
 import path from 'path';
 import { logger } from '../utils/logger.js';
-import { getProcessRegistry, isPidAlive, type ManagedProcessInfo, type ProcessRegistry } from './process-registry.js';
+import {
+  getProcessRegistry,
+  verifyPidFileOwnership,
+  type ManagedProcessInfo,
+  type PidInfo,
+  type ProcessRegistry
+} from './process-registry.js';
 import { runShutdownCascade } from './shutdown.js';
 import { startHealthChecker, stopHealthChecker } from './health-checker.js';
 
 const DATA_DIR = path.join(homedir(), '.claude-mem');
 const PID_FILE = path.join(DATA_DIR, 'worker.pid');
 
-interface PidInfo {
-  pid: number;
-  port: number;
-  startedAt: string;
-}
-
 interface ValidateWorkerPidOptions {
   logAlive?: boolean;
   pidFilePath?: string;
@@ -182,7 +182,7 @@ export function validateWorkerPidFile(options: ValidateWorkerPidOptions = {}): V
     return 'invalid';
   }
 
-  if (isPidAlive(pidInfo.pid)) {
+  if (verifyPidFileOwnership(pidInfo)) {
     if (options.logAlive ?? true) {
       logger.info('SYSTEM', 'Worker already running (PID alive)', {
         existingPid: pidInfo.pid,
@@ -193,7 +193,7 @@ export function validateWorkerPidFile(options: ValidateWorkerPidOptions = {}): V
     return 'alive';
   }
 
-  logger.info('SYSTEM', 'Removing stale PID file (worker process is dead)', {
+  logger.info('SYSTEM', 'Removing stale PID file (worker process is dead or PID has been reused)', {
     pid: pidInfo.pid,
     port: pidInfo.port,
     startedAt: pidInfo.startedAt

src/supervisor/process-registry.ts

@@ -1,4 +1,4 @@
-import { ChildProcess } from 'child_process';
+import { ChildProcess, spawnSync } from 'child_process';
 import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'fs';
 import { homedir } from 'os';
 import path from 'path';
@@ -44,6 +44,134 @@ export function isPidAlive(pid: number): boolean {
   }
 }
 
+export interface PidInfo {
+  pid: number;
+  port: number;
+  startedAt: string;
+  // Opaque process-start token used to distinguish a worker incarnation from
+  // another process that happens to reuse the same PID. Captured via
+  // captureProcessStartToken() at write time, checked via
+  // verifyPidFileOwnership() at read time. Optional for backwards
+  // compatibility with PID files written by older versions.
+  startToken?: string;
+}
+
+/**
+ * Capture an opaque "identity" token for a running PID — something stable
+ * across time for that exact process incarnation, but different if the PID
+ * gets reused by a later process.
+ *
+ * Fixes a class of false-positive "worker already running" errors where the
+ * PID file survives (bind-mounted volume, persistent home dir, etc.) while
+ * the PID namespace resets (docker stop / docker start), and the new worker
+ * incarnation happens to get the same PID as the old one. A plain kill(0)
+ * liveness check then says "yes, PID is alive" — but it's actually *us*
+ * checking against our own PID file and refusing to boot.
+ *
+ * Sources by platform (`process.platform`):
+ * - `linux`: field 22 of /proc/<pid>/stat (starttime, jiffies since boot).
+ *   Cheap, no exec. Same approach pgrep/systemd use.
+ * - `darwin` and any other POSIX (*BSD, SunOS) that falls through the Linux
+ *   check: `ps -p <pid> -o lstart=` (wall-clock start time). A one-shot exec
+ *   at worker startup — fine. If `ps` is missing the ENOENT is caught and
+ *   null is returned; callers then fall back to liveness-only.
+ * - `win32`: null (caller falls back to liveness-only behavior). The PID-
+ *   reuse scenario doesn't affect Windows deployments the way containers do.
+ *
+ * Returns null when we can't read a token (permission denied, process gone,
+ * unsupported platform). Callers should treat null as "can't verify" and
+ * fall back to the liveness-only code path to preserve existing behavior.
+ */
+export function captureProcessStartToken(pid: number): string | null {
+  if (!Number.isInteger(pid) || pid <= 0) return null;
+
+  if (process.platform === 'linux') {
+    try {
+      // /proc/<pid>/stat format:
+      //   <pid> (comm) <state> <ppid> ... <starttime@field-22> ...
+      // `comm` can contain spaces and parens, so we key off the LAST ')' and
+      // split the tail — avoids being confused by weird process names.
+      const raw = readFileSync(`/proc/${pid}/stat`, 'utf-8');
+      const tailStart = raw.lastIndexOf(') ');
+      if (tailStart < 0) return null;
+      const fields = raw.slice(tailStart + 2).split(' ');
+      // After ') ' we're at field 3 (state). starttime is field 22.
+      // Offset into `fields`: 22 - 3 = 19.
+      const starttime = fields[19];
+      return starttime && /^\d+$/.test(starttime) ? starttime : null;
+    } catch (error: unknown) {
+      logger.debug('SYSTEM', 'captureProcessStartToken: /proc read failed', {
+        pid,
+        error: error instanceof Error ? error.message : String(error)
+      });
+      return null;
+    }
+  }
+
+  if (process.platform === 'win32') {
+    return null;
+  }
+
+  try {
+    // Pin LC_ALL=C so `ps lstart=` emits a locale-independent timestamp
+    // (e.g. `Mon Apr 21 09:00:00 2026`). Without this, a bind-mounted PID
+    // file written under one locale and read under another would hash to
+    // different tokens and the new worker would incorrectly treat itself
+    // as a stale prior incarnation — reintroducing the bug this helper
+    // exists to prevent. Flagged by Greptile on PR #2082.
+    const result = spawnSync('ps', ['-p', String(pid), '-o', 'lstart='], {
+      encoding: 'utf-8',
+      timeout: 2000,
+      env: { ...process.env, LC_ALL: 'C', LANG: 'C' }
+    });
+    if (result.status !== 0) return null;
+    const token = result.stdout.trim();
+    return token.length > 0 ? token : null;
+  } catch (error: unknown) {
+    logger.debug('SYSTEM', 'captureProcessStartToken: ps exec failed', {
+      pid,
+      error: error instanceof Error ? error.message : String(error)
+    });
+    return null;
+  }
+}
+
+/**
+ * Verify that the process named by `info` is the same worker incarnation
+ * that wrote the PID file. Returns true only when:
+ *   - the PID is currently alive, AND
+ *   - either the stored start token matches the current token for that PID,
+ *     OR no token is stored (PID file written by an older version — fall
+ *     back to liveness-only for backwards compatibility).
+ *
+ * Returns false for null input, dead PIDs, and token mismatches. A token
+ * mismatch means the PID has been reused by an unrelated process — the PID
+ * file is stale even though kill(0) succeeds.
+ */
+export function verifyPidFileOwnership(info: PidInfo | null): info is PidInfo {
+  if (!info) return false;
+  if (!isPidAlive(info.pid)) return false;
+
+  if (!info.startToken) return true;
+
+  const currentToken = captureProcessStartToken(info.pid);
+  if (currentToken === null) return true;
+
+  const match = currentToken === info.startToken;
+  if (!match) {
+    // Emit a debug signal when liveness passes but identity fails — the
+    // exact container-restart scenario this helper exists to catch. Without
+    // this log the callers just say "stale" and can't distinguish
+    // "process dead" from "PID reused by a different process".
+    logger.debug('SYSTEM', 'verifyPidFileOwnership: start-token mismatch (PID reused)', {
+      pid: info.pid,
+      stored: info.startToken,
+      current: currentToken
+    });
+  }
+  return match;
+}
+
 export class ProcessRegistry {
   private readonly registryPath: string;
   private readonly entries = new Map<string, ManagedProcessInfo>();

tests/infrastructure/process-manager.test.ts

@@ -16,6 +16,8 @@ import {
   spawnDaemon,
   resolveWorkerRuntimePath,
   runOneTimeChromaMigration,
+  captureProcessStartToken,
+  verifyPidFileOwnership,
   type PidInfo
 } from '../../src/services/infrastructure/index.js';
 
@@ -361,6 +363,121 @@ describe('ProcessManager', () => {
     });
   });
 
+  describe('captureProcessStartToken', () => {
+    const supported = process.platform === 'linux' || process.platform === 'darwin';
+
+    it.if(supported)('returns a non-empty token for the current process', () => {
+      const token = captureProcessStartToken(process.pid);
+      expect(typeof token).toBe('string');
+      expect((token ?? '').length).toBeGreaterThan(0);
+    });
+
+    it.if(supported)('returns a stable token across calls for the same PID', () => {
+      const first = captureProcessStartToken(process.pid);
+      const second = captureProcessStartToken(process.pid);
+      expect(first).toBe(second);
+    });
+
+    it('returns null for a non-existent PID', () => {
+      expect(captureProcessStartToken(2147483647)).toBeNull();
+    });
+
+    it('returns null for invalid PIDs', () => {
+      expect(captureProcessStartToken(0)).toBeNull();
+      expect(captureProcessStartToken(-1)).toBeNull();
+      expect(captureProcessStartToken(1.5)).toBeNull();
+      expect(captureProcessStartToken(NaN)).toBeNull();
+    });
+
+    it('returns null on win32 (liveness-only fallback path)', () => {
+      // Simulate Windows to exercise the documented fallback. Real CI doesn't
+      // run on win32, so without this mock the branch is uncovered.
+      const originalPlatform = process.platform;
+      Object.defineProperty(process, 'platform', { value: 'win32', configurable: true });
+      try {
+        expect(captureProcessStartToken(process.pid)).toBeNull();
+      } finally {
+        Object.defineProperty(process, 'platform', { value: originalPlatform, configurable: true });
+      }
+    });
+  });
+
+  describe('writePidFile (start-token capture)', () => {
+    const supported = process.platform === 'linux' || process.platform === 'darwin';
+
+    it.if(supported)('auto-captures a startToken when writing for the current process', () => {
+      writePidFile({ pid: process.pid, port: 37777, startedAt: new Date().toISOString() });
+      const persisted = readPidFile();
+      expect(persisted).not.toBeNull();
+      expect(typeof persisted!.startToken).toBe('string');
+      expect((persisted!.startToken ?? '').length).toBeGreaterThan(0);
+    });
+
+    it('preserves a caller-supplied startToken verbatim', () => {
+      const provided = 'caller-supplied-token-xyz';
+      writePidFile({ pid: process.pid, port: 37777, startedAt: new Date().toISOString(), startToken: provided });
+      const persisted = readPidFile();
+      expect(persisted!.startToken).toBe(provided);
+    });
+
+    it('omits startToken when the target PID has no readable token (dead PID)', () => {
+      // pid is dead, so captureProcessStartToken() returns null and writePidFile
+      // should not persist a startToken field.
+      writePidFile({ pid: 2147483647, port: 37777, startedAt: new Date().toISOString() });
+      const persisted = readPidFile();
+      expect(persisted).not.toBeNull();
+      expect(persisted!.startToken).toBeUndefined();
+    });
+  });
+
+  describe('verifyPidFileOwnership', () => {
+    const supported = process.platform === 'linux' || process.platform === 'darwin';
+
+    it('returns false for null input', () => {
+      expect(verifyPidFileOwnership(null)).toBe(false);
+    });
+
+    it('returns false when the PID is not alive', () => {
+      expect(verifyPidFileOwnership({
+        pid: 2147483647,
+        port: 37777,
+        startedAt: new Date().toISOString(),
+        startToken: 'anything'
+      })).toBe(false);
+    });
+
+    it('returns true when no startToken is stored (back-compat with older PID files)', () => {
+      expect(verifyPidFileOwnership({
+        pid: process.pid,
+        port: 37777,
+        startedAt: new Date().toISOString()
+        // intentionally no startToken
+      })).toBe(true);
+    });
+
+    it.if(supported)('returns true when the stored token matches the current PID', () => {
+      const token = captureProcessStartToken(process.pid);
+      expect(token).not.toBeNull();
+      expect(verifyPidFileOwnership({
+        pid: process.pid,
+        port: 37777,
+        startedAt: new Date().toISOString(),
+        startToken: token!
+      })).toBe(true);
+    });
+
+    it.if(supported)('returns false when the stored token does not match (PID reused)', () => {
+      // Simulates the container-restart bug: PID is alive (we pass our own),
+      // but the stored token was written by a prior incarnation.
+      expect(verifyPidFileOwnership({
+        pid: process.pid,
+        port: 37777,
+        startedAt: new Date().toISOString(),
+        startToken: 'token-from-a-different-incarnation'
+      })).toBe(false);
+    });
+  });
+
   describe('cleanStalePidFile', () => {
     it('should remove PID file when process is dead', () => {
       // Write a PID file with a non-existent PID

tests/supervisor/index.test.ts

@@ -68,6 +68,29 @@ describe('validateWorkerPidFile', () => {
     const status = validateWorkerPidFile({ logAlive: false, pidFilePath });
     expect(status).toBe('alive');
   });
+
+  // Regression: container restart (docker stop / docker start) reused low PIDs
+  // across boots. The PID file on a bind-mounted volume pointed at PID 11;
+  // the new worker also came up as PID 11. kill(0) returned "alive" and the
+  // worker refused to boot, thinking its own prior incarnation was still up.
+  // With the start-token identity check, a stored token that doesn't match
+  // the current PID's token should resolve as "stale" and the PID file should
+  // be cleared so the new worker can proceed.
+  const tokenSupported = process.platform === 'linux' || process.platform === 'darwin';
+  it.if(tokenSupported)('returns "stale" when startToken does not match the live PID (PID reused)', () => {
+    const tempDir = makeTempDir();
+    tempDirs.push(tempDir);
+    const pidFilePath = path.join(tempDir, 'worker.pid');
+    writeFileSync(pidFilePath, JSON.stringify({
+      pid: process.pid,
+      port: 37777,
+      startedAt: new Date().toISOString(),
+      startToken: 'token-from-a-different-incarnation'
+    }));
+
+    const status = validateWorkerPidFile({ logAlive: false, pidFilePath });
+    expect(status).toBe('stale');
+  });
 });
 
 describe('Supervisor assertCanSpawn behavior', () => {