test: prevent workers outliving parent

test-child-process-pass-fd.js parent can exit with an error on failure to fork, in which case it will leak child processes. Limit child lifetime to that of parent. Fixes: #9255 PR-URL: #9257 Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: sam-github

test/sequential/test-child-process-pass-fd.js

@@ -39,15 +39,23 @@ if (process.argv[2] !== 'child') {
  process.send('handle', socket);
  }
 
+ // As a side-effect, listening for the message event will ref the IPC channel,
+ // so the child process will stay alive as long as it has a parent process/IPC
+ // channel. Once this is done, we can unref our client and server sockets, and
+ // the only thing keeping this worker alive will be IPC. This is important,
+ // because it means a worker with no parent will have no referenced handles,
+ // thus no work to do, and will exit immediately, preventing process leaks.
+ process.on('message', function() {});
+
  const server = net.createServer((c) => {
  process.once('message', function(msg) {
  assert.strictEqual(msg, 'got');
  c.end('hello');
  });
  socketConnected();
- });
+ }).unref();
  server.listen(0, common.localhostIPv4, () => {
  const port = server.address().port;
- socket = net.connect(port, common.localhostIPv4, socketConnected);
+ socket = net.connect(port, common.localhostIPv4, socketConnected).unref();
  });
 }