fix(gateway): bound benchmark teardown waits

scripts/bench-gateway-restart.ts

@@ -173,6 +173,8 @@ const DEFAULT_TIMEOUT_MS = 30_000;
 const DEFAULT_POST_READY_DELAY_MS = 250;
 const DEFAULT_ENTRY = "dist/entry.js";
 const RESTART_INTENT_FILENAME = "gateway-restart-intent.json";
+const TEARDOWN_GRACE_MS = 2_000;
+const TEARDOWN_KILL_GRACE_MS = 1_000;
 
 const BASE_CONFIG = {
   browser: { enabled: false },
@@ -879,7 +881,10 @@ function writeRestartIntent(env: NodeJS.ProcessEnv, targetPid: number, reason: s
   }
 }
 
-async function stopChild(child: ChildProcessWithoutNullStreams): Promise<StopChildResult> {
+async function stopChild(
+  child: ChildProcessWithoutNullStreams,
+  options: { killGraceMs?: number; teardownGraceMs?: number } = {},
+): Promise<StopChildResult> {
   const currentExit = (): ChildExit | null =>
     child.exitCode != null || child.signalCode != null
       ? { exitCode: child.exitCode, signal: child.signalCode }
@@ -897,6 +902,8 @@ async function stopChild(child: ChildProcessWithoutNullStreams): Promise<StopChi
       resolve(observedExit);
     });
   });
+  const waitForExit = async (ms: number): Promise<ChildExit | null> =>
+    await Promise.race([exited, delay(ms).then(() => null)]);
 
   await new Promise<void>((resolve) => setImmediate(resolve));
   const queuedExit = observedExit ?? currentExit();
@@ -904,15 +911,39 @@ async function stopChild(child: ChildProcessWithoutNullStreams): Promise<StopChi
     return { ...queuedExit, exitedBeforeTeardown: true };
   }
 
+  const teardownGraceMs = options.teardownGraceMs ?? TEARDOWN_GRACE_MS;
+  const killGraceMs = options.killGraceMs ?? TEARDOWN_KILL_GRACE_MS;
   const sentTeardownSignal = killProcessTree(child, "SIGTERM");
-  const timeout = delay(2000).then(() => {
-    if (child.exitCode == null && child.signalCode == null) {
-      killProcessTree(child, "SIGKILL");
-    }
-    return exited;
-  });
-  const exit = await Promise.race([exited, timeout]);
-  return { ...exit, exitedBeforeTeardown: !sentTeardownSignal };
+  const gracefulExit = await waitForExit(teardownGraceMs);
+  if (gracefulExit != null) {
+    return { ...gracefulExit, exitedBeforeTeardown: !sentTeardownSignal };
+  }
+
+  const postGraceExit = currentExit() ?? observedExit;
+  if (postGraceExit != null) {
+    return { ...postGraceExit, exitedBeforeTeardown: !sentTeardownSignal };
+  }
+  if (!sentTeardownSignal) {
+    releaseUnsettledChild(child);
+    return { exitCode: null, exitedBeforeTeardown: true, signal: null };
+  }
+
+  killProcessTree(child, "SIGKILL");
+  const killedExit = await waitForExit(killGraceMs);
+  const finalExit = killedExit ?? currentExit() ?? observedExit;
+  if (finalExit != null) {
+    return { ...finalExit, exitedBeforeTeardown: false };
+  }
+
+  releaseUnsettledChild(child);
+  return { exitCode: null, exitedBeforeTeardown: false, signal: "SIGKILL" };
+}
+
+function releaseUnsettledChild(child: ChildProcessWithoutNullStreams): void {
+  child.stdin.destroy();
+  child.stdout.destroy();
+  child.stderr.destroy();
+  child.unref();
 }
 
 function killProcessTree(child: ChildProcessWithoutNullStreams, signal: NodeJS.Signals): boolean {
@@ -1559,7 +1590,8 @@ async function runGatewaySample(options: {
   const exit = await stopChild(child);
   clearInterval(rssTimer);
   sampleRss();
-  await childExitPromise.catch(() => null);
+  // stopChild is the bounded teardown wait; the raw exit promise may never settle.
+  void childExitPromise.catch(() => null);
   flushOutputLineBuffers(outputBuffers, onLine, performance.now() - sampleStartAt, {
     flushPartial: true,
   });

scripts/bench-gateway-startup.ts

@@ -109,6 +109,8 @@ const DEFAULT_RUNS = 5;
 const DEFAULT_WARMUP = 1;
 const DEFAULT_TIMEOUT_MS = 30_000;
 const DEFAULT_ENTRY = "dist/entry.js";
+const TEARDOWN_GRACE_MS = 2_000;
+const TEARDOWN_KILL_GRACE_MS = 1_000;
 
 const BASE_CONFIG = {
   browser: { enabled: false },
@@ -708,7 +710,10 @@ function sanitizedEnv(
   return env;
 }
 
-async function stopChild(child: ChildProcessWithoutNullStreams): Promise<StopChildResult> {
+async function stopChild(
+  child: ChildProcessWithoutNullStreams,
+  options: { killGraceMs?: number; teardownGraceMs?: number } = {},
+): Promise<StopChildResult> {
   const currentExit = (): ChildExit | null =>
     child.exitCode != null || child.signalCode != null
       ? { exitCode: child.exitCode, signal: child.signalCode }
@@ -726,6 +731,8 @@ async function stopChild(child: ChildProcessWithoutNullStreams): Promise<StopChi
       resolve(observedExit);
     });
   });
+  const waitForExit = async (ms: number): Promise<ChildExit | null> =>
+    await Promise.race([exited, delay(ms).then(() => null)]);
 
   await new Promise<void>((resolve) => setImmediate(resolve));
   const queuedExit = observedExit ?? currentExit();
@@ -733,15 +740,39 @@ async function stopChild(child: ChildProcessWithoutNullStreams): Promise<StopChi
     return { ...queuedExit, exitedBeforeTeardown: true };
   }
 
+  const teardownGraceMs = options.teardownGraceMs ?? TEARDOWN_GRACE_MS;
+  const killGraceMs = options.killGraceMs ?? TEARDOWN_KILL_GRACE_MS;
   const sentTeardownSignal = killProcessTree(child, "SIGTERM");
-  const timeout = delay(2000).then(() => {
-    if (child.exitCode == null && child.signalCode == null) {
-      killProcessTree(child, "SIGKILL");
-    }
-    return exited;
-  });
-  const exit = await Promise.race([exited, timeout]);
-  return { ...exit, exitedBeforeTeardown: !sentTeardownSignal };
+  const gracefulExit = await waitForExit(teardownGraceMs);
+  if (gracefulExit != null) {
+    return { ...gracefulExit, exitedBeforeTeardown: !sentTeardownSignal };
+  }
+
+  const postGraceExit = currentExit() ?? observedExit;
+  if (postGraceExit != null) {
+    return { ...postGraceExit, exitedBeforeTeardown: !sentTeardownSignal };
+  }
+  if (!sentTeardownSignal) {
+    releaseUnsettledChild(child);
+    return { exitCode: null, exitedBeforeTeardown: true, signal: null };
+  }
+
+  killProcessTree(child, "SIGKILL");
+  const killedExit = await waitForExit(killGraceMs);
+  const finalExit = killedExit ?? currentExit() ?? observedExit;
+  if (finalExit != null) {
+    return { ...finalExit, exitedBeforeTeardown: false };
+  }
+
+  releaseUnsettledChild(child);
+  return { exitCode: null, exitedBeforeTeardown: false, signal: "SIGKILL" };
+}
+
+function releaseUnsettledChild(child: ChildProcessWithoutNullStreams): void {
+  child.stdin.destroy();
+  child.stdout.destroy();
+  child.stderr.destroy();
+  child.unref();
 }
 
 function killProcessTree(child: ChildProcessWithoutNullStreams, signal: NodeJS.Signals): boolean {
@@ -1006,7 +1037,8 @@ async function runGatewaySample(options: {
   const exit = await stopChild(child);
   clearInterval(rssTimer);
   sampleRss();
-  await childExitPromise.catch(() => null);
+  // stopChild is the bounded teardown wait; the raw exit promise may never settle.
+  void childExitPromise.catch(() => null);
   rmSync(root, { force: true, maxRetries: 3, recursive: true, retryDelay: 100 });
 
   return {

test/scripts/bench-gateway-restart.test.ts

@@ -261,6 +261,42 @@ node    1234 user   12u  IPv4    0t0      TCP localhost:1234
     expect(child.kill).toHaveBeenCalledWith("SIGTERM");
   });
 
+  it("bounds teardown when the child ignores termination signals", async () => {
+    const child = new EventEmitter() as EventEmitter & {
+      exitCode: number | null;
+      kill: ReturnType<typeof vi.fn>;
+      signalCode: NodeJS.Signals | null;
+      stderr: { destroy: ReturnType<typeof vi.fn> };
+      stdin: { destroy: ReturnType<typeof vi.fn> };
+      stdout: { destroy: ReturnType<typeof vi.fn> };
+      unref: ReturnType<typeof vi.fn>;
+    };
+    child.exitCode = null;
+    child.signalCode = null;
+    child.kill = vi.fn(() => true);
+    child.stderr = { destroy: vi.fn() };
+    child.stdin = { destroy: vi.fn() };
+    child.stdout = { destroy: vi.fn() };
+    child.unref = vi.fn();
+
+    await expect(
+      testing.stopChild(child as unknown as Parameters<typeof testing.stopChild>[0], {
+        killGraceMs: 1,
+        teardownGraceMs: 1,
+      }),
+    ).resolves.toEqual({
+      exitedBeforeTeardown: false,
+      exitCode: null,
+      signal: "SIGKILL",
+    });
+    expect(child.kill).toHaveBeenNthCalledWith(1, "SIGTERM");
+    expect(child.kill).toHaveBeenNthCalledWith(2, "SIGKILL");
+    expect(child.stdin.destroy).toHaveBeenCalledOnce();
+    expect(child.stdout.destroy).toHaveBeenCalledOnce();
+    expect(child.stderr.destroy).toHaveBeenCalledOnce();
+    expect(child.unref).toHaveBeenCalledOnce();
+  });
+
   it("marks clean and signaled pre-teardown child exits as benchmark failures", () => {
     expect(
       testing.resolveSampleExitFailure({

test/scripts/bench-gateway-startup.test.ts

@@ -325,6 +325,42 @@ describe("gateway startup benchmark script", () => {
     expect(child.kill).toHaveBeenCalledWith("SIGTERM");
   });
 
+  it("bounds teardown when the child ignores termination signals", async () => {
+    const child = new EventEmitter() as EventEmitter & {
+      exitCode: number | null;
+      kill: ReturnType<typeof vi.fn>;
+      signalCode: NodeJS.Signals | null;
+      stderr: { destroy: ReturnType<typeof vi.fn> };
+      stdin: { destroy: ReturnType<typeof vi.fn> };
+      stdout: { destroy: ReturnType<typeof vi.fn> };
+      unref: ReturnType<typeof vi.fn>;
+    };
+    child.exitCode = null;
+    child.signalCode = null;
+    child.kill = vi.fn(() => true);
+    child.stderr = { destroy: vi.fn() };
+    child.stdin = { destroy: vi.fn() };
+    child.stdout = { destroy: vi.fn() };
+    child.unref = vi.fn();
+
+    await expect(
+      testing.stopChild(child as unknown as Parameters<typeof testing.stopChild>[0], {
+        killGraceMs: 1,
+        teardownGraceMs: 1,
+      }),
+    ).resolves.toEqual({
+      exitedBeforeTeardown: false,
+      exitCode: null,
+      signal: "SIGKILL",
+    });
+    expect(child.kill).toHaveBeenNthCalledWith(1, "SIGTERM");
+    expect(child.kill).toHaveBeenNthCalledWith(2, "SIGKILL");
+    expect(child.stdin.destroy).toHaveBeenCalledOnce();
+    expect(child.stdout.destroy).toHaveBeenCalledOnce();
+    expect(child.stderr.destroy).toHaveBeenCalledOnce();
+    expect(child.unref).toHaveBeenCalledOnce();
+  });
+
   it("collects Count-suffixed startup trace metrics", () => {
     const startupTrace: Record<string, number> = {};