WebSocket events fire synchronously during close() instead of asynchronously

[domenic]

Bug Description

When close() is called on a WebSocket in the CONNECTING state, the error and close events fire synchronously during the close() call, rather than being queued to fire asynchronously after close() returns.

Reproducible By

const { WebSocket } = require('undici');

const ws = new WebSocket('wss://echo.websocket.events/');

let closeReturned = false;

ws.addEventListener('error', () => {
  console.log('error event fired, closeReturned =', closeReturned);
});

ws.addEventListener('close', () => {
  console.log('close event fired, closeReturned =', closeReturned);
  process.exit(0);
});

console.log('Calling close()...');
ws.close();
closeReturned = true;
console.log('close() returned, closeReturned =', closeReturned);

setTimeout(() => {
  console.log('Timeout - no events fired');
  process.exit(1);
}, 5000);

Expected Behavior

Calling close()...
close() returned, closeReturned = true
error event fired, closeReturned = true
close event fired, closeReturned = true

See: https://jsbin.com/butegexadi/edit?html,js,output

This follows from the "queue a task" steps in in the spec: https://websockets.spec.whatwg.org/#:~:text=cleanly%2C-,the%20user%20agent%20must%20queue%20a%20task

Relevant WPTs:

• https://github.com/web-platform-tests/wpt/blob/master/websockets/interfaces/WebSocket/close/close-connecting.html
• https://github.com/web-platform-tests/wpt/blob/master/websockets/interfaces/WebSocket/close/close-connecting-async.any.js

Logs & Screenshots

Actual behavior:

Calling close()...
error event fired, closeReturned = false
close event fired, closeReturned = false

Environment

• Node v25.2.1
• undici 7.18.2