http: do not abort if socket is missing

Fixes: https://github.com/nodejs/node/issues/14368

PR-URL: https://github.com/nodejs/node/pull/14387
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

lib/_http_outgoing.js

@@ -642,7 +642,7 @@ OutgoingMessage.prototype.write = function write(chunk, encoding, callback) {
 function write_(msg, chunk, encoding, callback, fromEnd) {
   if (msg.finished) {
     var err = new Error('write after end');
-    nextTick(msg.socket[async_id_symbol],
+    nextTick(msg.socket && msg.socket[async_id_symbol],
              writeAfterEndNT.bind(msg),
              err,
              callback);

test/parallel/test-http-server-write-after-end.js

@@ -0,0 +1,27 @@
+'use strict';
+
+const common = require('../common');
+const http = require('http');
+const assert = require('assert');
+
+// Fix for https://github.com/nodejs/node/issues/14368
+
+const server = http.createServer(handle);
+
+function handle(req, res) {
+  res.on('error', common.mustCall((err) => {
+    assert.strictEqual(err.message, 'write after end');
+    server.close();
+  }));
+
+  res.write('hello');
+  res.end();
+
+  setImmediate(common.mustCall(() => {
+    res.write('world');
+  }));
+}
+
+server.listen(0, common.mustCall(() => {
+  http.get(`http://localhost:${server.address().port}`);
+}));