Fix dev server Ctrl-C shutdown wait

packages/server/scripts/dev-runner.ts

@@ -1,4 +1,4 @@
-import { spawnSync } from "node:child_process";
+import { spawn } from "node:child_process";
 import { fileURLToPath } from "url";
 import dotenv from "dotenv";
 
@@ -12,34 +12,44 @@ const inspectArg = process.env.PASEO_NODE_INSPECT ?? "--inspect";
 const inspectArgs =
   inspectArg === "0" || inspectArg === "false" || inspectArg === "off" ? [] : [inspectArg];
 
-// The supervisor handles SIGINT/SIGTERM itself and needs time to drain the
-// worker gracefully. Ignore them here so spawnSync blocks until the supervisor
-// finishes shutting down, instead of the parent dying on Ctrl-C and releasing
-// the shell while the daemon is still logging.
-process.on("SIGINT", () => {});
-process.on("SIGTERM", () => {});
+const supervisorArgs = [
+  ...inspectArgs,
+  "--heapsnapshot-near-heap-limit=3",
+  "--max-old-space-size=3072",
+  "--report-on-fatalerror",
+  "--report-directory=/tmp/paseo-reports",
+  ...process.execArgv,
+  daemonRunnerEntry,
+  "--dev",
+  ...process.argv.slice(2),
+];
 
-const result = spawnSync(
-  process.execPath,
-  [
-    ...inspectArgs,
-    "--heapsnapshot-near-heap-limit=3",
-    "--max-old-space-size=3072",
-    "--report-on-fatalerror",
-    "--report-directory=/tmp/paseo-reports",
-    ...process.execArgv,
-    daemonRunnerEntry,
-    "--dev",
-    ...process.argv.slice(2),
-  ],
-  {
-    stdio: "inherit",
-    env: process.env,
-  },
-);
+const supervisor = spawn(process.execPath, supervisorArgs, {
+  stdio: "inherit",
+  env: process.env,
+});
 
-if (result.error) {
-  throw result.error;
+function exitCodeForSignal(signal: NodeJS.Signals): number {
+  return signal === "SIGINT" ? 130 : 1;
 }
 
-process.exit(result.status ?? 1);
+function forwardSignal(signal: NodeJS.Signals): void {
+  if (supervisor.exitCode !== null || supervisor.signalCode !== null || supervisor.killed) {
+    return;
+  }
+  supervisor.kill(signal);
+}
+
+// The supervisor handles SIGINT/SIGTERM itself and needs time to drain the
+// worker gracefully. Keep this wrapper alive until the supervisor exits so npm
+// does not release the shell while the daemon is still logging final shutdown.
+process.on("SIGINT", () => forwardSignal("SIGINT"));
+process.on("SIGTERM", () => forwardSignal("SIGTERM"));
+
+supervisor.on("error", (error) => {
+  throw error;
+});
+
+supervisor.on("exit", (code, signal) => {
+  process.exit(code ?? (signal ? exitCodeForSignal(signal) : 1));
+});

packages/server/scripts/supervision-parity.test.ts

@@ -14,4 +14,12 @@ describe("supervision parity", () => {
 
     expect(daemonRunnerCalls + devRunnerCalls).toBe(1);
   });
+
+  test("dev runner waits asynchronously for supervisor shutdown", () => {
+    const devRunner = readFileSync(new URL("./dev-runner.ts", import.meta.url), "utf8");
+
+    expect(devRunner).toContain('import { spawn } from "node:child_process"');
+    expect(devRunner).not.toContain("spawnSync");
+    expect(devRunner).toContain('supervisor.on("exit"');
+  });
 });