Fix #1907 where the never-ending loop prevention used a coersion comparison...

Fix #1907 where the never-ending loop prevention used a coersion comparison which sometimes dropped values incorrectly.  Also fixed a bug where on deep copies the target copied over itself (i = 2 addition).  Last made code handle the case when a property might have a string in it that should be overwritten by an object.

src/core.js

@@ -516,8 +516,14 @@ jQuery.extend = jQuery.fn.extend = function() {
 	if ( target.constructor == Boolean ) {
 		deep = target;
 		target = arguments[1] || {};
+		// skip the boolean and the target
+		i = 2;
 	}
 
+	// Handle case when target is a string or something (possible in deep copy)
+	if ( typeof target != "object" )
+		target = {};
+
 	// extend jQuery itself if only one argument is passed
 	if ( length == 1 ) {
 		target = this;
@@ -530,12 +536,12 @@ jQuery.extend = jQuery.fn.extend = function() {
 			// Extend the base object
 			for ( var name in options ) {
 				// Prevent never-ending loop
-				if ( target == options[ name ] )
+				if ( target === options[ name ] )
 					continue;
 
 				// Recurse if we're merging object values
 				if ( deep && typeof options[ name ] == "object" && target[ name ] && !options[ name ].nodeType )
-					jQuery.extend( target[ name ], options[ name ] );
+					target[ name ] = jQuery.extend( target[ name ], options[ name ] );
 
 				// Don't bring in undefined values
 				else if ( options[ name ] != undefined )

test/unit/core.js

@@ -811,7 +811,7 @@ test("is(String)", function() {
 });
 
 test("$.extend(Object, Object)", function() {
-	expect(11);
+	expect(14);
 
 	var settings = { xnumber1: 5, xnumber2: 7, xstring1: "peter", xstring2: "pan" },
 		options =     { xnumber2: 1, xstring2: "x", xxx: "newstring" },
@@ -836,6 +836,17 @@ test("$.extend(Object, Object)", function() {
 	isObj( deep2.foo, deep2copy.foo, "Check if not deep2: options must not be modified" );
 	equals( deep1.foo2, document, "Make sure that a deep clone was not attempted on the document" );
 
+	var target = {};
+	var recursive = { foo:target, bar:5 };
+	jQuery.extend(true, target, recursive);
+	isObj( target, { bar:5 }, "Check to make sure a recursive obj doesn't go never-ending loop by not copying it over" );
+
+	var ret = jQuery.extend(true, { foo: [] }, { foo: [0] } ); // 1907
+	ok( ret.foo.length == 1, "Check to make sure a value with coersion 'false' copies over when necessary to fix #1907" );
+
+	var ret = jQuery.extend(true, { foo: "1,2,3" }, { foo: [1, 2, 3] } );
+	ok( typeof ret.foo != "string", "Check to make sure values equal with coersion (but not actually equal) overwrite correctly" );
+
 	var defaults = { xnumber1: 5, xnumber2: 7, xstring1: "peter", xstring2: "pan" },
 		defaultsCopy = { xnumber1: 5, xnumber2: 7, xstring1: "peter", xstring2: "pan" },
 		options1 =     { xnumber2: 1, xstring2: "x" },