fix(cli): use process.execPath for macOS launchd autostart (#9156)

bin/cli/runtime/processSupervisor.mjs

@@ -52,8 +52,11 @@ export class ServerSupervisor {
     // silently, so a boot that never becomes ready looked like a dead hang with zero
     // output even at APP_LOG_LEVEL=debug. Pipe stdout too and buffer it alongside
     // stderr so a readiness timeout can surface what the child actually printed.
+    // #9156: macOS launchd cannot resolve bare "node" because its PATH is
+    // minimal. Always use process.execPath (the absolute path to the running
+    // Node.js binary) so the supervisor never depends on PATH resolution.
     this.child = spawn(
-      process.versions.bun ? process.execPath : "node",
+      process.execPath,
       process.versions.bun
         ? [this.serverPath]
         : buildNodeRuntimeArgs(process.env, this.memoryLimit, this.serverPath),

changelog.d/fixes/9156-macos-autostart-execpath.md

@@ -0,0 +1 @@
+- fix(cli): use process.execPath for macOS launchd autostart

tests/unit/repro-9156.test.ts

@@ -0,0 +1,111 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import path from "node:path";
+
+// #9156: macOS launchd autostart fails because the supervisor spawns the child
+// with bare "node", but launchd's PATH cannot resolve it. process.execPath is
+// always the absolute path to the running Node.js binary and is always resolvable.
+//
+// We verify the fix via:
+//   1. Static source analysis — the spawn() call must use process.execPath
+//      unconditionally (no fallback to bare "node"). This runs without any
+//      experimental flags so it serves as the permanent regression guard.
+//   2. Runtime test via mock.module (requires --experimental-test-module-mocks)
+//      that captures the actual spawn arguments.
+
+const __filename = new URL(import.meta.url).pathname;
+const __dirname = path.dirname(__filename);
+
+const SUPERVISOR_PATH = path.resolve(
+  __dirname,
+  "../../bin/cli/runtime/processSupervisor.mjs"
+);
+const supervisorSrc = fs.readFileSync(SUPERVISOR_PATH, "utf8");
+
+// ---------------------------------------------------------------------------
+// 1. Source-level verification (no experimental flag required)
+// ---------------------------------------------------------------------------
+
+test("spawn() uses process.execPath unconditionally, no bare 'node' fallback (#9156)", () => {
+  // Must NOT contain the old conditional that falls back to bare "node"
+  assert.ok(
+    !supervisorSrc.includes('process.versions.bun ? process.execPath : "node"'),
+    "must NOT have a conditional fallback to bare 'node'"
+  );
+
+  // Must use process.execPath as the first argument to spawn()
+  const execPathPattern = /spawn\(\s*process\.execPath\s*,/;
+  assert.ok(
+    execPathPattern.test(supervisorSrc),
+    "spawn() must receive process.execPath as first argument"
+  );
+});
+
+test("process.execPath is an absolute path to the running Node.js binary", () => {
+  assert.ok(
+    path.isAbsolute(process.execPath),
+    `process.execPath must be absolute, got: ${process.execPath}`
+  );
+  assert.ok(
+    fs.existsSync(process.execPath),
+    `process.execPath must exist: ${process.execPath}`
+  );
+});
+
+// ---------------------------------------------------------------------------
+// 2. Runtime test via mock.module (requires --experimental-test-module-mocks)
+// ---------------------------------------------------------------------------
+//
+// Run manually: node --experimental-test-module-mocks --import tsx/esm --test tests/unit/repro-9156.test.ts
+
+import { mock } from "node:test";
+
+if (typeof mock.module === "function") {
+  test("(runtime) ServerSupervisor.start() spawns with process.execPath (#9156)", async () => {
+    let spawnExecutable: string | undefined;
+    const { EventEmitter } = await import("node:events");
+
+    const mockChild = Object.assign(new EventEmitter(), {
+      pid: 12345,
+      stdout: null,
+      stderr: null,
+      kill: () => {},
+    });
+
+    mock.module("node:child_process", {
+      exports: {
+        spawn: (...args: unknown[]) => {
+          spawnExecutable = args[0] as string;
+          return mockChild;
+        },
+      },
+    });
+
+    process.env.PORT = "0";
+
+    const { ServerSupervisor } = await import(
+      "../../bin/cli/runtime/processSupervisor.mjs"
+    );
+
+    const supervisor = new ServerSupervisor({
+      serverPath: "/fake/server.js",
+      env: {},
+      maxRestarts: 0,
+    });
+
+    spawnExecutable = undefined;
+    supervisor.start();
+
+    assert.ok(spawnExecutable, "spawn() must have been called");
+    assert.equal(
+      spawnExecutable,
+      process.execPath,
+      `expected process.execPath, got: ${spawnExecutable}`
+    );
+    assert.notEqual(spawnExecutable, "node", "must not be bare 'node'");
+
+    mockChild.removeAllListeners();
+    delete process.env.PORT;
+  });
+}