Make sure that data properties with hyphens are always accessed/set using camelCase. Fixes #9124.

src/data.js

@@ -98,7 +98,7 @@ jQuery.extend({
 		}
 
 		if ( data !== undefined ) {
-			thisCache[ name ] = data;
+			thisCache[ jQuery.camelCase( name ) ] = data;
 		}
 
 		// TODO: This is a hack for 1.5 ONLY. It will be removed in 1.6. Users should
@@ -108,7 +108,7 @@ jQuery.extend({
 			return thisCache[ internalKey ] && thisCache[ internalKey ].events;
 		}
 
-		return getByName ? thisCache[ name ] : thisCache;
+		return getByName ? thisCache[ jQuery.camelCase( name ) ] : thisCache;
 	},
 
 	removeData: function( elem, name, pvt /* Internal Use Only */ ) {

test/unit/data.js

@@ -488,7 +488,7 @@ if (window.JSON && window.JSON.stringify) {
 }
 
 test("jQuery.data should follow html5 specification regarding camel casing", function() {
-	expect(6);
+	expect(8);
 
 	var div = jQuery("<div id='myObject' data-foo='a' data-foo-bar='b' data-foo-bar-baz='c'></div>")
 		.prependTo("body");
@@ -501,5 +501,10 @@ test("jQuery.data should follow html5 specification regarding camel casing", fun
 	equals(div.data("fooBar"), "b", "Verify multiple word data-* key");
 	equals(div.data("fooBarBaz"), "c", "Verify multiple word data-* key");
 
+	div.data("foo-bar", "d");
+
+	equals(div.data("fooBar"), "d", "Verify updated data-* key");
+	equals(div.data("foo-bar"), "d", "Verify updated data-* key");
+
 	div.remove();
-});
\ No newline at end of file
+});