fix(ext/node): implement timeout and killSignal for spawn() (#32283)

Fixes the `timeout` and `killSignal` options for `child_process.spawn()`
(and `fork()`, which delegates to `spawn()`). Previously these options
were accepted but silently ignored.

The fix sets a `setTimeout` after spawning that kills the child with the
specified `killSignal` (default: `"SIGTERM"`) if the process hasn't
exited within `timeout` ms. The timer is cleared if the process exits
naturally before the deadline.

Author: fraidev

ext/node/polyfills/child_process.ts

@@ -222,9 +222,27 @@ export function spawn(
   options = normalizeSpawnArguments(command, args, options);
 
   validateAbortSignal(options?.signal, "options.signal");
+  validateTimeout(options?.timeout);
 
   const child = new ChildProcess();
   child.spawn(options);
+
+  const timeout = options?.timeout;
+  if (timeout != null && timeout > 0) {
+    const killSignal = options?.killSignal ?? "SIGTERM";
+    let timeoutId: ReturnType<typeof setTimeout> | null = setTimeout(() => {
+      timeoutId = null;
+      child.kill(killSignal as string);
+    }, timeout);
+
+    child.once("exit", () => {
+      if (timeoutId) {
+        clearTimeout(timeoutId);
+        timeoutId = null;
+      }
+    });
+  }
+
   return child;
 }
 

ext/node/polyfills/internal/child_process.ts

@@ -1471,13 +1471,7 @@ function _createSpawnError(
 }
 
 export interface SpawnOptions extends ChildProcessOptions {
-  /**
-   * NOTE: This option is not yet implemented.
-   */
   timeout?: number;
-  /**
-   * NOTE: This option is not yet implemented.
-   */
   killSignal?: string;
 }
 

tests/node_compat/config.jsonc

@@ -191,6 +191,7 @@
     "parallel/test-child-process-fork-no-shell.js": {},
     "parallel/test-child-process-fork-ref.js": {},
     "parallel/test-child-process-fork-ref2.js": {},
+    "parallel/test-child-process-fork-timeout-kill-signal.js": {},
     "parallel/test-child-process-fork3.js": {},
     "parallel/test-child-process-ipc-next-tick.js": {},
     "parallel/test-child-process-no-deprecation.js": {},
@@ -201,6 +202,7 @@
     "parallel/test-child-process-silent.js": {},
     "parallel/test-child-process-spawn-error.js": {},
     "parallel/test-child-process-spawn-event.js": {},
+    "parallel/test-child-process-spawn-timeout-kill-signal.js": {},
     "parallel/test-child-process-spawn-typeerror.js": {},
     "parallel/test-child-process-spawnsync-args.js": {},
     "parallel/test-child-process-spawnsync-env.js": {},