fix(autopilot): close the engine on SIGTERM/SIGINT instead of hard-exiting (#1872)

systemctl stop (SIGTERM) previously hard-exited autopilot without ever
closing the engine. On PGLite the cycle steps run INLINE in the autopilot
process, so a mid-write exit kills WASM Postgres with the WAL dirty and
can corrupt the brain.

Now both exit paths close the engine first:
- autopilot's own shutdown() (SIGINT + internal stops like max_crashes /
  cycle-failure-cap) aborts the in-flight inline cycle via an
  AbortController threaded into runCycle, drains it briefly, and awaits
  engine.disconnect() before process.exit(0).
- process-cleanup's SIGTERM handler (installed at cli.ts module load,
  exits within its 3s cleanup deadline) reaches the same closeEngine via
  a registered 'autopilot-engine-close' cleanup callback.

PGLite's disconnect() drains the pending query and checkpoints before
closing; a second call is a no-op, so both paths firing is safe.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/commands/autopilot.ts

@@ -38,6 +38,7 @@ import { logSelfUpgrade } from '../core/audit/self-upgrade-audit.ts';
 import { detectInstallMethod } from './upgrade.ts';
 import { evaluateQuietHours } from '../core/minions/quiet-hours.ts';
 import { inspectLock } from '../core/db-lock.ts';
+import { registerCleanup } from '../core/process-cleanup.ts';
 
 /**
  * v0.37.7.0 #1162 — classify autopilot reconnect-loop errors.
@@ -433,6 +434,37 @@ export async function runAutopilot(engine: BrainEngine, args: string[]) {
   let stopping = false;
   let childSupervisor: ChildWorkerSupervisor | null = null;
 
+  // #1872: graceful engine shutdown. On PGLite the cycle steps run INLINE in
+  // this process, so a hard `process.exit` mid-write (systemctl stop →
+  // SIGTERM) kills WASM Postgres with the WAL dirty and can corrupt the
+  // brain. Two exit paths must both close the engine:
+  //   - autopilot's own shutdown() below (owns SIGINT + internal stops like
+  //     max_crashes / cycle-failure-cap), and
+  //   - process-cleanup's SIGTERM handler (installed at cli.ts module load;
+  //     it runs the cleanup registry with a 3s deadline and then exits) —
+  //     which is why closeEngine is ALSO registered there.
+  // closeEngine aborts the in-flight inline cycle (runCycle checks the
+  // signal between phases and threads it into phase sub-work), gives it a
+  // short bounded window to wind down, then disconnects. PGLite's
+  // disconnect() drains the pending query and checkpoints before closing;
+  // a second call is a no-op (disconnect snapshots + nulls the handle), so
+  // both paths firing is safe.
+  const shutdownAbort = new AbortController();
+  let inflightInlineCycle: Promise<unknown> | null = null;
+  const closeEngine = async () => {
+    shutdownAbort.abort(new Error('autopilot shutdown'));
+    if (inflightInlineCycle) {
+      // ponytail: 2s cap keeps us inside process-cleanup's 3s deadline; a
+      // between-phase abort resolves instantly, a mid-phase one may not.
+      await Promise.race([
+        inflightInlineCycle.catch(() => { /* cycle errors already logged by the loop */ }),
+        new Promise((r) => setTimeout(r, 2_000)),
+      ]);
+    }
+    try { await engine.disconnect(); } catch { /* best-effort */ }
+  };
+  const deregisterEngineClose = registerCleanup('autopilot-engine-close', closeEngine);
+
   if (spawnManagedWorker) {
     const cliPath = resolveGbrainCliPath();
     // Cgroup-aware auto-sized RSS watchdog cap (issue #1678). The old flat
@@ -520,6 +552,10 @@ export async function runAutopilot(engine: BrainEngine, args: string[]) {
         childSupervisor.killChild('SIGKILL');
       }
     }
+    // #1872: abort the in-flight inline cycle and close the engine BEFORE
+    // process.exit — a hard exit mid-write corrupts PGLite's WASM Postgres.
+    await closeEngine();
+    deregisterEngineClose();
     try { unlinkSync(lockPath); } catch { /* already gone */ }
     process.exit(0);
   };
@@ -1008,16 +1044,21 @@ export async function runAutopilot(engine: BrainEngine, args: string[]) {
       // path's phase set). Now both converge on the same primitive.
       try {
         const { runCycle } = await import('../core/cycle.ts');
-        const report = await runCycle(engine, {
+        // #1872: track the promise so closeEngine can drain it on shutdown,
+        // and pass the abort signal so the cycle winds down between phases.
+        const cyclePromise = runCycle(engine, {
           brainDir: repoPath,
           // Autopilot daemon path: pulls by default (matches
           // pre-v0.17 autopilot behavior). CLI dream defaults false
           // for cron safety; that choice is scoped to dream only.
           pull: true,
+          signal: shutdownAbort.signal,
           yieldBetweenPhases: async () => {
             await new Promise(r => setImmediate(r));
           },
         });
+        inflightInlineCycle = cyclePromise;
+        const report = await cyclePromise.finally(() => { inflightInlineCycle = null; });
         // Only 'failed' (every attempted phase failed) trips the autopilot
         // circuit breaker. 'partial' means at least one phase warned or
         // failed while others ran — that's a soft signal, not a fatal

test/autopilot-shutdown-engine-close.test.ts

@@ -0,0 +1,63 @@
+/**
+ * #1872 — autopilot SIGTERM/SIGINT must close the engine before exit.
+ *
+ * On PGLite the cycle steps run INLINE in the autopilot process, so a hard
+ * `process.exit` mid-write (systemctl stop → SIGTERM) kills WASM Postgres
+ * with the WAL dirty and can corrupt the brain. Two exit paths must both
+ * close the engine:
+ *
+ *   - autopilot's own shutdown() (owns SIGINT + internal stops like
+ *     max_crashes / cycle-failure-cap), and
+ *   - process-cleanup's SIGTERM handler (installed at cli.ts module load,
+ *     which exits within its 3s cleanup deadline) — reached via the
+ *     registered 'autopilot-engine-close' cleanup callback.
+ *
+ * Because the shutdown path is deep inside `runAutopilot()` (a long-running
+ * daemon loop that ends in process.exit), a behavioral test would have to
+ * spawn + signal a real daemon. Following the established precedent
+ * (test/autopilot-supervisor-wiring.test.ts, test/autopilot-fanout-wiring.test.ts),
+ * these static-shape regressions pin the load-bearing wiring instead.
+ */
+import { describe, expect, it } from 'bun:test';
+import { readFileSync } from 'fs';
+import { join } from 'path';
+
+const AUTOPILOT_SRC = readFileSync(
+  join(import.meta.dir, '..', 'src', 'commands', 'autopilot.ts'),
+  'utf8',
+);
+
+describe('autopilot.ts graceful engine shutdown (#1872)', () => {
+  it('registers an engine-close callback in the process-cleanup registry (SIGTERM path)', () => {
+    // process-cleanup owns SIGTERM (installed at cli.ts:10) and hard-exits
+    // after its cleanup pass; without this registration the engine is never
+    // closed on `systemctl stop`.
+    expect(AUTOPILOT_SRC).toContain(
+      "import { registerCleanup } from '../core/process-cleanup.ts';",
+    );
+    expect(AUTOPILOT_SRC).toContain(
+      "registerCleanup('autopilot-engine-close', closeEngine)",
+    );
+  });
+
+  it('closeEngine aborts the in-flight inline cycle then disconnects the engine', () => {
+    // Abort first (runCycle checks the signal between phases and threads it
+    // into phase sub-work), bounded drain, then disconnect.
+    expect(AUTOPILOT_SRC).toMatch(
+      /const closeEngine = async \(\) => \{[\s\S]{0,900}shutdownAbort\.abort\([\s\S]{0,900}engine\.disconnect\(\)/,
+    );
+  });
+
+  it('the inline runCycle call carries the shutdown abort signal and is tracked as in-flight', () => {
+    // PGLite / --inline path: the cycle runs in-process, so shutdown must be
+    // able to (a) signal it to wind down and (b) await it before closing.
+    expect(AUTOPILOT_SRC).toMatch(/signal:\s*shutdownAbort\.signal/);
+    expect(AUTOPILOT_SRC).toMatch(/inflightInlineCycle\s*=\s*cyclePromise/);
+  });
+
+  it('shutdown() awaits closeEngine() before process.exit(0) (SIGINT + internal-stop path)', () => {
+    expect(AUTOPILOT_SRC).toMatch(
+      /await closeEngine\(\);[\s\S]{0,400}process\.exit\(0\)/,
+    );
+  });
+});