http: fix leaked error listener on sync HTTP req create + destroy · nodejs/node@64f15c2

Destroy the request. Optionally emit an `'error'` event,

and emit a `'close'` event. Calling this will cause remaining data

in the response to be dropped and the socket to be destroyed.

in the response to be dropped, and the socket to be destroyed if used,

or returned to the corresponding Agent pool otherwise if possible.

See [`writable.destroy()`][] for further details.

if (socket) {

if (!err && req.agent && !socket.destroyed) {

socket.emit('free');

socket.removeListener('error', socketErrorListener);

} else {

finished(socket.destroy(err || req[kError]), (er) => {

if (er?.code === 'ERR_STREAM_PREMATURE_CLOSE') {

'use strict';

const common = require('../common');

const assert = require('assert');

const http = require('http');

const { defaultMaxListeners } = require('events');

// Immediately destroying an HTTP request must not leak listeners on the

// freed socket. When sockets are reused via a keep-alive agent leaked

// listeners would accumulate to trigger a MaxListenersExceededWarning.

// Check we don't get a MaxListenersExceededWarning:

process.on('warning', common.mustNotCall('Unexpected warning emitted'));

const server = http.createServer(common.mustNotCall());

server.listen(0, common.mustCall(() => {

const agent = new http.Agent({ keepAlive: true });

const port = server.address().port;

// Count actual socket creations to confirm reuse:

let createSocketCount = 0;

const origCreateSocket = agent.createSocket.bind(agent);

agent.createSocket = function(...args) {

createSocketCount++;

return origCreateSocket(...args);

};

function executeHttpGet() {

return new Promise((resolve) => {

const req = http.get({ host: '127.0.0.1', port, agent });

req.on('error', resolve);

req.on('close', resolve);

req.on('response', common.mustNotCall());

req.destroy();

});

}

async function main() {

for (let i = 0; i < defaultMaxListeners + 1; i++) {

await executeHttpGet();

}

assert.strictEqual(createSocketCount, 1);

server.close();

agent.destroy();

}

main().then(common.mustCall());

}));