[PATCH] fix emitter.on()/addListener()'s check for listener leak

0001-fix-emitter.on-addListener-s-check-for-listener-leak.patch

From 843eb784adcb379ae6fc53af558cd94ce2f25f1c Mon Sep 17 00:00:00 2001
From: koichik <koichik@improvement.jp>
Date: Mon, 17 Jan 2011 19:30:43 +0900
Subject: [PATCH] fix emitter.on()/addListener()'s check for listener leak

Because the check is performed before a listener is added to an array,
the warning occurred with the 12th listener not the 11th listener.

example:

var emitter = new events.EventEmitter();
for (var i = 0; i < 10; i++) {
  emitter.on('data', function() {});
}
emitter.on('data', function() {}); // 11th, no warning
emitter.on('data', function() {}); // 12th, warning occurred
---
 lib/events.js                                      |    2 +-
 .../test-event-emitter-check-listener-leaks.js     |   29 ++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletions(-)
 create mode 100644 test/simple/test-event-emitter-check-listener-leaks.js

diff --git a/lib/events.js b/lib/events.js
index 6505606..aa4d960 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -92,7 +92,7 @@ EventEmitter.prototype.addListener = function(type, listener) {
         m = defaultMaxListeners;
       }
 
-      if (m && m > 0 && this._events[type].length > m) {
+      if (m && m > 0 && this._events[type].length >= m) {
         this._events[type].warned = true;
         console.error('(node) warning: possible EventEmitter memory ' +
                       'leak detected. %d listeners added. ' +
diff --git a/test/simple/test-event-emitter-check-listener-leaks.js b/test/simple/test-event-emitter-check-listener-leaks.js
new file mode 100644
index 0000000..66e257c
--- /dev/null
+++ b/test/simple/test-event-emitter-check-listener-leaks.js
@@ -0,0 +1,29 @@
+var assert = require('assert');
+var events = require('events');
+
+var e = new events.EventEmitter();
+
+// default
+for (var i = 0; i < 10; i++) {
+  e.on('default', function() {});
+}
+assert.ok(!e._events['default'].hasOwnProperty('warned'));
+e.on('default', function() {});
+assert.ok(e._events['default'].warned);
+
+// specific
+e.setMaxListeners(5);
+for (var i = 0; i < 5; i++) {
+  e.on('specific', function() {});
+}
+assert.ok(!e._events['specific'].hasOwnProperty('warned'));
+e.on('specific', function() {});
+assert.ok(e._events['specific'].warned);
+
+// unlimited
+e.setMaxListeners(0);
+for (var i = 0; i < 1000; i++) {
+  e.on('unlimited', function() {});
+}
+assert.ok(!e._events['unlimited'].hasOwnProperty('warned'));
+
-- 
1.7.1