http: emit close as the last event in the client

Emit close event after all other events in the client, e.g.
error will be emitted before close.

PR-URL: https://github.com/nodejs/node/pull/15588
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/_http_client.js

@@ -346,7 +346,6 @@ function socketCloseListener() {
   // NOTE: It's important to get parser here, because it could be freed by
   // the `socketOnData`.
   var parser = socket.parser;
-  req.emit('close');
   if (req.res && req.res.readable) {
     // Socket closed before we emitted 'end' below.
     req.res.emit('aborted');
@@ -362,6 +361,7 @@ function socketCloseListener() {
     req.socket._hadError = true;
     req.emit('error', createHangUpError());
   }
+  req.emit('close');
 
   // Too bad.  That output wasn't getting written.
   // This is pretty terrible that it doesn't raise an error.

test/parallel/test-http-client-close-event.js

@@ -0,0 +1,30 @@
+'use strict';
+const common = require('../common');
+
+// This test ensures that the `'close'` event is emitted after the `'error'`
+// event when a request is made and the socket is closed before we started to
+// receive a response.
+
+const assert = require('assert');
+const http = require('http');
+
+const server = http.createServer(common.mustNotCall());
+
+server.listen(0, common.mustCall(() => {
+  const req = http.get({ port: server.address().port }, common.mustNotCall());
+  let errorEmitted = false;
+
+  req.on('error', (err) => {
+    errorEmitted = true;
+    assert.strictEqual(err.constructor, Error);
+    assert.strictEqual(err.message, 'socket hang up');
+    assert.strictEqual(err.code, 'ECONNRESET');
+  });
+
+  req.on('close', common.mustCall(() => {
+    assert.strictEqual(errorEmitted, true);
+    server.close();
+  }));
+
+  req.destroy();
+}));