child_process: don't die when disconnect event exists

lib/child_process.js

@@ -455,11 +455,14 @@ exports._forkChild = function(fd) {
   p.unref();
   setupChannel(process, p);
 
+  var refs = 0;
   process.on('newListener', function(name) {
-    if (name == 'message' && this.listeners('message').length == 0) p.ref();
+    if (name !== 'message' && name !== 'disconnect') return;
+    if (++refs === 1) p.ref();
   });
   process.on('removeListener', function(name) {
-    if (name == 'message' && this.listeners('message').length == 0) p.unref();
+    if (name !== 'message' && name !== 'disconnect') return;
+    if (--refs === 0) p.unref();
   });
 };
 

test/simple/test-child-process-fork-ref.js

@@ -0,0 +1,57 @@
+// 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 fork = require('child_process').fork;
+
+if (process.argv[2] === 'child') {
+  process.send('1');
+
+  // check that child don't instantly die
+  setTimeout(function() {
+    process.send('2');
+  }, 200);
+
+  process.on('disconnect', function () {
+    process.stdout.write('3');
+  });
+
+} else {
+  var child = fork(__filename, ['child'], {silent: true});
+
+  var ipc = [], stdout = '';
+
+  child.on('message', function (msg) {
+    ipc.push(msg);
+
+    if (msg === '2') child.disconnect();
+  });
+
+  child.stdout.on('data', function (chunk) {
+    stdout += chunk;
+  });
+
+  child.once('exit', function () {
+    assert.deepEqual(ipc, ['1', '2']);
+    assert.equal(stdout, '3');
+  });
+}