Update cloneCopyEvent so that it does not create superfluous data objects when cloning elements. Exposes a new method, $.hasData. Fixes #7165. Thanks to DaveMethvin and iliakan for their help.

src/data.js

@@ -9,7 +9,7 @@ jQuery.extend({
 	// Please use with caution
 	uuid: 0,
 
-	// Unique for each copy of jQuery on the page	
+	// Unique for each copy of jQuery on the page
 	expando: "jQuery" + jQuery.now(),
 
 	// The following elements throw uncatchable exceptions if you
@@ -21,6 +21,14 @@ jQuery.extend({
 		"applet": true
 	},
 
+	hasData: function( elem ) {
+		if ( elem.nodeType ) {
+			elem = jQuery.cache[ elem[jQuery.expando] ];
+		}
+
+		return !!elem && !jQuery.isEmptyObject(elem);
+	},
+
 	data: function( elem, name, data ) {
 		if ( !jQuery.acceptData( elem ) ) {
 			return;
@@ -144,7 +152,7 @@ jQuery.fn.extend({
 					var attr = this[0].attributes, name;
 					for ( var i = 0, l = attr.length; i < l; i++ ) {
 						name = attr[i].name;
-	
+
 						if ( name.indexOf( "data-" ) === 0 ) {
 							name = name.substr( 5 );
 							dataAttr( this[0], name, data[ name ] );

src/manipulation.js

@@ -370,14 +370,18 @@ function root( elem, cur ) {
 }
 
 function cloneCopyEvent(orig, ret) {
-	var i = 0;
+	ret.each(function (nodeIndex) {
-
+		if ( this.nodeType !== 1 || !jQuery.hasData(orig[nodeIndex]) ) {
-	ret.each(function() {
-		if ( this.nodeType !== 1 || this.nodeName !== (orig[i] && orig[i].nodeName) ) {
 			return;
 		}
 
-		var oldData = jQuery.data( orig[i++] ),
+		// XXX remove for 1.5 RC or merge back in if there is actually a reason for this check that has been
+		// unexposed by unit tests
+		if ( this.nodeName !== (orig[nodeIndex] && orig[nodeIndex].nodeName) ) {
+			throw "Cloned data mismatch";
+		}
+
+		var oldData = jQuery.data( orig[nodeIndex] ),
 			curData = jQuery.data( this, oldData ),
 			events = oldData && oldData.events;
 

test/unit/data.js

@@ -78,6 +78,21 @@ test("jQuery.data", function() {
 	ok( jQuery.data( window, "BAD" ), "Make sure that the value was set." );
 });
 
+test("jQuery.hasData", function() {
+	expect(6);
+
+	function testData(obj) {
+		equals( jQuery.hasData(obj), false, "No data exists" );
+		jQuery.data( obj, "foo", "bar" );
+		equals( jQuery.hasData(obj), true, "Data exists" );
+		jQuery.removeData( obj, "foo" );
+		equals( jQuery.hasData(obj), false, "Data was removed" );
+	}
+
+	testData(document.createElement('div'));
+	testData({});
+});
+
 test(".data()", function() {
 	expect(5);
 
@@ -180,7 +195,7 @@ test(".data(String) and .data(String, Object)", function() {
 	equals( $elem.data('emptyString','').data('emptyString'), '', "Empty strings are preserved");
 	equals( $elem.data('false',false).data('false'), false, "false's are preserved");
 	equals( $elem.data('exists'), true, "Existing data is returned" );
-	
+
 	// Clean up
 	$elem.removeData();
 	ok( jQuery.isEmptyObject( $elem[0] ), "removeData clears the object" );
@@ -191,7 +206,7 @@ test("data-* attributes", function() {
 	var div = jQuery("<div>"),
 		child = jQuery("<div data-myobj='old data' data-ignored=\"DOM\" data-other='test'></div>"),
 		dummy = jQuery("<div data-myobj='old data' data-ignored=\"DOM\" data-other='test'></div>");
-		
+
 	equals( div.data("attr"), undefined, "Check for non-existing data-attr attribute" );
 
 	div.attr("data-attr", "exists");
@@ -199,10 +214,10 @@ test("data-* attributes", function() {
 
 	div.attr("data-attr", "exists2");
 	equals( div.data("attr"), "exists", "Check that updates to data- don't update .data()" );
-		
+
 	div.data("attr", "internal").attr("data-attr", "external");
 	equals( div.data("attr"), "internal", "Check for .data('attr') precedence (internal > external data-* attribute)" );
-	
+
 	child.appendTo('#main');
 	equals( child.data("myobj"), "old data", "Value accessed from data-* attribute");
 
@@ -249,7 +264,7 @@ test("data-* attributes", function() {
 		.attr("data-space", " ")
 		.attr("data-null", "null")
 		.attr("data-string", "test");
-	
+
 	strictEqual( child.data('true'), true, "Primitive true read from attribute");
 	strictEqual( child.data('false'), false, "Primitive false read from attribute");
 	strictEqual( child.data('five'), 5, "Primitive number read from attribute");
@@ -265,7 +280,7 @@ test("data-* attributes", function() {
 	strictEqual( child.data('string'), "test", "Typical string read from attribute");
 
 	child.remove();
-	
+
 	// tests from metadata plugin
 	function testData(index, elem) {
 		switch (index) {
@@ -289,10 +304,10 @@ test("data-* attributes", function() {
 			ok(false, ["Assertion failed on index ", index, ", with data ", data].join(''));
 		}
 	}
-	
+
 	var metadata = '<ol><li class="test test2" data-foo="bar" data-bar="baz" data-arr="[1,2]">Some stuff</li><li class="test test2" data-test="bar" data-bar="baz">Some stuff</li><li class="test test2" data-zoooo="bar" data-bar=\'{"test":"baz"}\'>Some stuff</li><li class="test test2" data-number=true data-stuff="[2,8]">Some stuff</li></ol>',
 		elem = jQuery(metadata).appendTo('#main');
-	
+
 	elem.find("li").each(testData);
 	elem.remove();
 });
@@ -305,12 +320,12 @@ test(".data(Object)", function() {
 	div.data({ "test": "in", "test2": "in2" });
 	equals( div.data("test"), "in", "Verify setting an object in data" );
 	equals( div.data("test2"), "in2", "Verify setting an object in data" );
-	
+
 	var obj = {test:"unset"},
 		jqobj = jQuery(obj);
 	jqobj.data({ "test": "in", "test2": "in2" });
 	equals( obj.test, "in", "Verify setting an object on an object extends the object" );
-	equals( obj.test2, "in2", "Verify setting an object on an object extends the object" );	
+	equals( obj.test2, "in2", "Verify setting an object on an object extends the object" );
 });
 
 test("jQuery.removeData", function() {
@@ -324,13 +339,13 @@ test("jQuery.removeData", function() {
 	jQuery.removeData( div );
 	ok( !jQuery.data(div, "test2"), "Make sure that the data property no longer exists." );
 	ok( !div[ jQuery.expando ], "Make sure the expando no longer exists, as well." );
-	
+
 	var obj = {};
 	jQuery.data(obj, "test", "testing");
 	equals( obj.test, "testing", "verify data on plain object");
 	jQuery.removeData(obj, "test");
 	equals( jQuery.data(obj, "test"), undefined, "Check removal of data on plain object" );
-	equals( obj.test, undefined, "Check removal of data directly from plain object" );	
+	equals( obj.test, undefined, "Check removal of data directly from plain object" );
 
 	jQuery.data( window, "BAD", true );
 	jQuery.removeData( window, "BAD" );

test/unit/manipulation.js

@@ -51,7 +51,7 @@ test("text(Function) with incoming value", function() {
 });
 
 var testWrap = function(val) {
-	expect(18);
+	expect(19);
 	var defaultText = 'Try them out:'
 	var result = jQuery('#first').wrap(val( '<div class="red"><span></span></div>' )).text();
 	equals( defaultText, result, 'Check for wrapping of on-the-fly html' );
@@ -80,10 +80,20 @@ var testWrap = function(val) {
 	equals( jQuery("#nonnodes > i").text(), j.text(), "Check node,textnode,comment wraps doesn't hurt text" );
 
 	// Try wrapping a disconnected node
+	var cacheLength = 0;
+	for (var i in jQuery.cache) {
+		cacheLength++;
+	}
+
 	j = jQuery("<label/>").wrap(val( "<li/>" ));
 	equals( j[0].nodeName.toUpperCase(), "LABEL", "Element is a label" );
 	equals( j[0].parentNode.nodeName.toUpperCase(), "LI", "Element has been wrapped" );
 
+	for (i in jQuery.cache) {
+		cacheLength--;
+	}
+	equals(cacheLength, 0, "No memory leak in jQuery.cache (bug #7165)");
+
 	// Wrap an element containing a text node
 	j = jQuery("<span/>").wrap("<div>test</div>");
 	equals( j[0].previousSibling.nodeType, 3, "Make sure the previous node is a text element" );
@@ -856,7 +866,7 @@ test("replaceAll(String|Element|Array&lt;Element&gt;|jQuery)", function() {
 });
 
 test("clone()", function() {
-	expect(36);
+	expect(37);
 	equals( 'This is a normal link: Yahoo', jQuery('#en').text(), 'Assert text for #en' );
 	var clone = jQuery('#yahoo').clone();
 	equals( 'Try them out:Yahoo', jQuery('#first').append(clone).text(), 'Check for clone' );
@@ -914,10 +924,12 @@ test("clone()", function() {
 	equals( clone.html(), div.html(), "Element contents cloned" );
 	equals( clone[0].nodeName.toUpperCase(), "DIV", "DIV element cloned" );
 
-	div = jQuery("<div/>").data({ a: true, b: true });
+	div = jQuery("<div/>").data({ a: true });
-	div = div.clone(true);
+	var div2 = div.clone(true);
-	equals( div.data("a"), true, "Data cloned." );
+	equals( div2.data("a"), true, "Data cloned." );
-	equals( div.data("b"), true, "Data cloned." );
+	div2.data("a", false);
+	equals( div2.data("a"), false, "Ensure cloned element data object was correctly modified" );
+	equals( div.data("a"), true, "Ensure cloned element data object is copied, not referenced" );
 
 	var form = document.createElement("form");
 	form.action = "/test/";