fix(connection): fixing leak in 3.0.0

Author: daprahamian

Diff for: lib/connection/connection.js

@@ -600,7 +600,7 @@ Connection.prototype.connect = function(_options) {
     });
     self.connection.setTimeout(self.connectionTimeout);
   } else {
-    self.connection.on('connect', function() {
+    self.connection.once('connect', function() {
       // Set socket timeout instead of connection timeout
       self.connection.setTimeout(self.socketTimeout);
       // Emit connect event

Diff for: test/tests/functional/pool_tests.js

@@ -39,6 +39,36 @@ describe('Pool tests', function() {
     }
   });
 
+  it('Should only listen on connect once', {
+    metadata: { requires: { topology: 'single' } },
+
+    test: function(done) {
+      // Enable connections accounting
+      Connection.enableConnectionAccounting();
+
+      // Attempt to connect
+      var pool = new Pool(null, {
+        host: this.configuration.host,
+        port: this.configuration.port,
+        bson: new Bson(),
+        messageHandler: function() {}
+      });
+
+      // Add event listeners
+      pool.on('connect', function(_pool) {
+        var connections = _pool.allConnections();
+        expect(connections).to.have.lengthOf(1).and.to.have;
+        expect(connections[0].connection.listenerCount('connect')).to.equal(1);
+        _pool.destroy();
+        Connection.disableConnectionAccounting();
+        done();
+      });
+
+      // Start connection
+      pool.connect();
+    }
+  });
+
   it('should correctly write ismaster operation to the server', {
     metadata: { requires: { topology: 'single' } },