Call extend on prop to avoid changing original properties so that per-property...

Call extend on prop to avoid changing original properties so that per-property easing is not lost in multiple animations with the same props

src/effects.js

@@ -126,6 +126,9 @@ jQuery.fn.extend({
 			return this.each( optall.complete, [ false ] );
 		}
 
+		// Do not change referenced properties as per-property easing will be lost
+		prop = jQuery.extend( {}, prop );
+
 		return this[ optall.queue === false ? "each" : "queue" ](function() {
 			// XXX 'this' does not always have a nodeName when running the
 			// test suite
@@ -158,7 +161,7 @@ jQuery.fn.extend({
 				// easing resolution: per property > opt.specialEasing > opt.easing > 'swing' (default)
 				if ( jQuery.isArray( val ) ) {
 					opt.animatedProperties[ name ] = val[ 1 ];
-					val = val[ 0 ];
+					val = prop[ name ] = val[ 0 ];
 				} else {
 					opt.animatedProperties[ name ] = opt.specialEasing && opt.specialEasing[ name ] || opt.easing || 'swing';
 				}

test/unit/effects.js

@@ -923,13 +923,18 @@ test("jQuery.show('fast') doesn't clear radio buttons (bug #1095)", function ()
 
 test("animate with per-property easing", function(){
 
-	expect(3);
+	expect(5);
 	stop();
 
 	var data = { a:0, b:0, c:0 },
 		_test1_called = false,
 		_test2_called = false,
-		_default_test_called = false;
+		_default_test_called = false,
+		props = {
+			a: [ 100, "_test1" ],
+			b: [ 100, "_test2" ],
+			c: 100
+		};
 
 	jQuery.easing["_test1"] = function(p) {
 		_test1_called = true;
@@ -946,16 +951,14 @@ test("animate with per-property easing", function(){
 		return p;
 	};
 
-	jQuery(data).animate({
-		a: [100, "_test1"],
-		b: [100, "_test2"],
-		c: 100
-	}, 400, "_default_test", function(){
+	jQuery(data).animate( props, 400, "_default_test", function(){
 		start();
 
 		ok( _test1_called, "Easing function (_test1) called" );
 		ok( _test2_called, "Easing function (_test2) called" );
 		ok( _default_test_called, "Easing function (_default) called" );
+		equal( props.a[ 1 ], "_test1", "animate does not change original props (per-property easing would be lost)");
+		equal( props.b[ 1 ], "_test2", "animate does not change original props (per-property easing would be lost)");
 	});
 
 });