jquery core: Closes #3641. jQuery.merge stopped looping once a 0 was …

…found.

src/core.js

@@ -1149,12 +1149,12 @@ jQuery.extend({
 		// Also, we need to make sure that the correct elements are being returned
 		// (IE returns comment nodes in a '*' query)
 		if ( !jQuery.support.getAll ) {
-			while ( (elem = second[ i++ ]) )
+			while ( (elem = second[ i++ ]) != null )
 				if ( elem.nodeType != 8 )
 					first[ pos++ ] = elem;
 
 		} else
-			while ( (elem = second[ i++ ]) )
+			while ( (elem = second[ i++ ]) != null )
 				first[ pos++ ] = elem;
 
 		return first;

test/unit/core.js

@@ -1138,6 +1138,21 @@ test("is(String)", function() {
 	ok( jQuery('#en').is('[lang="de"] , [lang="en"]'), 'Comma-seperated; Check for lang attribute: Expect en or de' );
 });
 
+test("jQuery.merge()", function() {
+	var parse = jQuery.merge;
+
+	same( parse([],[]), [], "Empty arrays" );
+
+	same( parse([1],[2]), [1,2], "Basic" );
+	same( parse([1,2],[3,4]), [1,2,3,4], "Basic" );
+
+	same( parse([1,2],[]), [1,2], "Second empty" );
+	same( parse([],[1,2]), [1,2], "First empty" );	
+
+	// Fixed at [5998], #3641
+	same( parse([-2,-1], [0,1,2]), [-2,-1,0,1,2], "Second array including a zero (falsy)");
+});
+
 test("jQuery.extend(Object, Object)", function() {
 	expect(20);