Unhandled 'error' event on aborted request

[lpinca]

• Version: v8.17.0, v10.23.1, v12.20.1, v14.15.4, v15.5.1
• Platform: Darwin imac.local 20.2.0 Darwin Kernel Version 20.2.0: Wed Dec 2 20:39:59 PST 2020; root:xnu-7195.60.75~1/RELEASE_X86_64 x86_64
• Subsystem: http

What steps will reproduce the bug?

$ cat test.js 
const http = require('http');

const req = http.get('http://[2604:1380:45f1:3f00::1]:4002');

req.on('error', console.error);
req.abort();

$ node test.js 
node:events:353
      throw er; // Unhandled 'error' event
      ^

Error: connect EHOSTUNREACH 2604:1380:45f1:3f00::1:4002 - Local (:::49474)
    at internalConnect (node:net:910:16)
    at defaultTriggerAsyncIdScope (node:internal/async_hooks:430:12)
    at node:net:1001:9
    at processTicksAndRejections (node:internal/process/task_queues:75:11)
Emitted 'error' event on Socket instance at:
    at emitErrorNT (node:internal/streams/destroy:188:8)
    at emitErrorCloseNT (node:internal/streams/destroy:153:3)
    at processTicksAndRejections (node:internal/process/task_queues:80:21) {
  errno: -65,
  code: 'EHOSTUNREACH',
  syscall: 'connect',
  address: '2604:1380:45f1:3f00::1',
  port: 4002
}

How often does it reproduce? Is there a required condition?

Always. No required condition.

What is the expected behavior?

The error is handled by the 'error' event listener.

What do you see instead?

The error is not handled.

Additional information

If req.abort() is removed the error is correctly handled.

[lpinca]

onSocketNT() is called before the 'error' event is emitted but there are no listeners. The listener is added by tickOnSocket().

cc: @nodejs/http

[ronag]

https://github.com/nodejs/node/blob/v15.5.1/lib/_http_client.js#L808-L809

[lpinca]

@ronag it's not that. The error is emitted after onSocketNT() is called. Adding an 'error' listener here https://github.com/nodejs/node/blob/v15.5.1/lib/_http_client.js#L814-L819 would be sufficient.

[ronag]

Might have been solved with #36863

[ronag]

Needs a regression test either way.

[lpinca]

#36863 fixes this only if no agent is used. It does not fix the example in the issue description.