Moved too-early assignment inside the if stmt where the var is actually used. Close gh-1292.

.mailmap

@@ -91,3 +91,4 @@ Yehuda Katz <wycats@gmail.com> <wycats@12-189-125-93.att-inc.com>
 Yehuda Katz <wycats@gmail.com> <wycats@mobile005.mycingular.net>
 Yehuda Katz <wycats@gmail.com> <wycats@Yehuda-Katz.local>
 Yiming He <yiminghe@gmail.com>
+Terry Jones <terry@jon.es> <terry@fluidinfo.com>

src/callbacks.js

@@ -171,9 +171,9 @@ jQuery.Callbacks = function( options ) {
 			},
 			// Call all callbacks with the given context and arguments
 			fireWith: function( context, args ) {
-				args = args || [];
-				args = [ context, args.slice ? args.slice() : args ];
 				if ( list && ( !fired || stack ) ) {
+					args = args || [];
+					args = [ context, args.slice ? args.slice() : args ];
 					if ( firing ) {
 						stack.push( args );
 					} else {