http: fix memory leak when socket dns lookup occurs error (#348)

src/js/http_client.js

@@ -104,7 +104,6 @@ function setupConnection(req, socket) {
   socket.on('data', socketOnData);
   socket.on('end', socketOnEnd);
   socket.on('close', socketOnClose);
-  socket.on('lookup', socketOnLookup);
 
   // socket emitted when a socket is assigned to req
   process.nextTick(function() {
@@ -166,10 +165,6 @@ function socketOnError(err) {
   emitError(this, err);
 }
 
-function socketOnLookup(err, ip, family) {
-  emitError(this, err);
-}
-
 function socketOnData(d) {
   var socket = this;
   var req = this._httpMessage;

src/js/net.js

@@ -141,10 +141,7 @@ Socket.prototype.connect = function() {
     self.emit('lookup', err, ip, family);
 
     if (err) {
-      process.nextTick(function() {
-        self.emit('error', err);
-        self.destroy();
-      });
+      emitError(self, err);
     } else {
       resetSocketTimeout(self);
       process.nextTick(function() {

test/run_pass/test_net_http_dns_error.js

@@ -0,0 +1,19 @@
+var assert = require('assert');
+var http = require('http');
+var common = require('../common');
+
+var host = 'www.unable-to-resolved-host.rokid.com';
+var req = http.request({ host: host });
+
+req.socket.on('finish', common.mustCall(() => {
+  process.nextTick(() => {
+    var destroyed = req.socket._socketState.destroyed;
+    console.log(`socket is destroyed ${host}:`, destroyed);
+    assert.equal(destroyed, true);
+  });
+}));
+
+// handle error event to prevent the process throw an error
+req.on('error', common.mustCall((err) => {
+  console.log('request error', err.message);
+}));

test/testsets.json

@@ -79,6 +79,7 @@
     { "name": "test_net_connect.js" },
     { "name": "test_net_end.js" },
     { "name": "test_net_headers.js" },
+    { "name": "test_net_http_dns_error.js" },
     { "name": "test_net_http_get.js" },
     { "name": "test_net_http_response_twice.js" },
     { "name": "test_net_http_request_response.js", "skip": ["nuttx"], "reason": "not implemented for nuttx" },