http: cleanup freeSockets when socket destroyed

If the socket was destroyed, we need to remove it from the agent's
`freeSockets` list, otherwise dead socket could be reused by new
request.

lib/_http_agent.js

@@ -229,17 +229,24 @@ Agent.prototype.createSocket = function(req, options) {
 
 Agent.prototype.removeSocket = function(s, options) {
   var name = this.getName(options);
-  debug('removeSocket', name);
-  if (this.sockets[name]) {
-    var index = this.sockets[name].indexOf(s);
-    if (index !== -1) {
-      this.sockets[name].splice(index, 1);
-      if (this.sockets[name].length === 0) {
-        // don't leak
-        delete this.sockets[name];
+  debug('removeSocket', name, 'destroyed:', s.destroyed);
+  var sets = [this.sockets];
+
+  // If the socket was destroyed, remove it from the free buffers too.
+  if (s.destroyed)
+    sets.push(this.freeSockets);
+
+  sets.forEach(function(sockets) {
+    if (sockets[name]) {
+      var index = sockets[name].indexOf(s);
+      if (index !== -1) {
+        sockets[name].splice(index, 1);
+        // Don't leak
+        if (sockets[name].length === 0)
+          delete sockets[name];
       }
     }
-  }
+  });
   if (this.requests[name] && this.requests[name].length) {
     debug('removeSocket, have a request, make a socket');
     var req = this.requests[name][0];

test/simple/test-http-agent-keepalive.js

@@ -0,0 +1,144 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+var http = require('http');
+var Agent = require('_http_agent').Agent;
+var EventEmitter = require('events').EventEmitter;
+
+var agent = new Agent({
+  keepAlive: true,
+  keepAliveMsecs: 1000,
+  maxSockets: 5,
+  maxFreeSockets: 5,
+});
+
+var server = http.createServer(function (req, res) {
+  if (req.url === '/error') {
+    res.destroy();
+    return;
+  } else if (req.url === '/remote_close') {
+    // cache the socket, close it after 100ms
+    var socket = res.connection;
+    setTimeout(function () {
+      socket.end();
+    }, 100);
+  }
+  res.end('hello world');
+});
+
+function get(path, callback) {
+  return agent.get({
+    host: 'localhost',
+    port: common.PORT,
+    path: path
+  }, callback);
+}
+
+var name = 'localhost:' + common.PORT + '::';
+
+function checkDataAndSockets(body) {
+  assert.equal(body.toString(), 'hello world');
+  assert.equal(agent.sockets[name].length, 1);
+  assert.equal(agent.freeSockets[name], undefined);
+}
+
+function second() {
+  // request second, use the same socket
+  get('/second', function (res) {
+    assert.equal(res.statusCode, 200);
+    res.on('data', checkDataAndSockets);
+    res.on('end', function () {
+      assert.equal(agent.sockets[name].length, 1);
+      assert.equal(agent.freeSockets[name], undefined);
+      process.nextTick(function () {
+        assert.equal(agent.sockets[name], undefined);
+        assert.equal(agent.freeSockets[name].length, 1);
+        remoteClose();
+      });
+    });
+  });
+}
+
+function remoteClose() {
+  // mock remote server close the socket
+  get('/remote_close', function (res) {
+    assert.deepEqual(res.statusCode, 200);
+    res.on('data', checkDataAndSockets);
+    res.on('end', function () {
+      assert.equal(agent.sockets[name].length, 1);
+      assert.equal(agent.freeSockets[name], undefined);
+      process.nextTick(function () {
+        assert.equal(agent.sockets[name], undefined);
+        assert.equal(agent.freeSockets[name].length, 1);
+        // waitting remote server close the socket
+        setTimeout(function () {
+          assert.equal(agent.sockets[name], undefined);
+          assert.equal(agent.freeSockets[name], undefined,
+            'freeSockets is not empty');
+          remoteError();
+        }, 200);
+      });
+    });
+  });
+}
+
+function remoteError() {
+  // remove server will destroy ths socket
+  var req = get('/error', function (res) {
+    throw new Error('should not call this function');
+  });
+  req.on('error', function (err) {
+    assert.ok(err);
+    assert.equal(err.message, 'socket hang up');
+    assert.equal(agent.sockets[name].length, 1);
+    assert.equal(agent.freeSockets[name], undefined);
+    // Wait socket 'close' event emit
+    setTimeout(function () {
+      assert.equal(agent.sockets[name], undefined);
+      assert.equal(agent.freeSockets[name], undefined);
+      done();
+    }, 1);
+  });
+}
+
+function done() {
+  console.log('http keepalive agent test success.');
+  process.exit(0);
+}
+
+server.listen(common.PORT, function() {
+  // request first, and keep alive
+  get('/first', function (res) {
+    assert.equal(res.statusCode, 200);
+    res.on('data', checkDataAndSockets);
+    res.on('end', function () {
+      assert.equal(agent.sockets[name].length, 1);
+      assert.equal(agent.freeSockets[name], undefined);
+      process.nextTick(function () {
+        assert.equal(agent.sockets[name], undefined);
+        assert.equal(agent.freeSockets[name].length, 1);
+        second();
+      });
+    });
+  });
+});