cluster: disconnect event was not emitted correctly

Fix for nodejs#1304
Inside of a worker, disconnect event was not emitted on cluster.worker

lib/cluster.js

@@ -509,6 +509,7 @@ function workerInit() {
     });
     cluster.worker = worker;
     process.once('disconnect', function() {
+      worker.emit('disconnect');
       if (!worker.suicide) {
         // Unexpected disconnect, master exited, or some such nastiness, so
         // worker exits immediately.

test/parallel/test-cluster-worker-disconnect.js

@@ -1,13 +1,20 @@
 var common = require('../common');
 var assert = require('assert');
 var cluster = require('cluster');
+var fs = require('fs');
+var path = require('path');
 
 if (cluster.isWorker) {
   var http = require('http');
   http.Server(function() {
 
   }).listen(common.PORT, '127.0.0.1');
 
+  // Save flag-file on disconnect
+  cluster.worker.on('disconnect', function(){
+    fs.writeFileSync(path.join(__dirname, process.pid + ''), '');
+  });
+
 } else if (cluster.isMaster) {
 
   var checks = {
@@ -18,6 +25,7 @@ if (cluster.isWorker) {
     },
     worker: {
       emitDisconnect: false,
+      emitDisconnectInsideWorker: false,
       emitExit: false,
       state: false,
       suicideMode: false,
@@ -62,6 +70,15 @@ if (cluster.isWorker) {
   worker.once('exit', function() {
     checks.worker.emitExit = true;
     checks.worker.died = !alive(worker.process.pid);
+
+    var flagFile = path.join(__dirname, worker.process.pid + '');
+    checks.worker.emitDisconnectInsideWorker = fs.existsSync(flagFile);
+
+    // cleanup
+    if (checks.worker.emitDisconnectInsideWorker) {
+      fs.unlinkSync(flagFile);
+    }
+
     process.nextTick(function() {
       process.exit(0);
     });
@@ -74,6 +91,7 @@ if (cluster.isWorker) {
 
     // events
     assert.ok(w.emitDisconnect, 'Disconnect event did not emit');
+    assert.ok(w.emitDisconnectInsideWorker, 'Disconnect event did not emit inside worker');
     assert.ok(c.emitDisconnect, 'Disconnect event did not emit');
     assert.ok(w.emitExit, 'Exit event did not emit');
     assert.ok(c.emitExit, 'Exit event did not emit');