Fix issue where Opera 9.x returns incorrect results on certain Selector queries with descendant combinators. [#395 state:resolved] (Arpan, fearphage, kangax, Andrew Dupont)

CHANGELOG

@@ -1,6 +1,8 @@
+* Fix issue where Opera 9.x returns incorrect results on certain Selector queries with descendant combinators. [#395 state:resolved] (Arpan, fearphage, kangax, Andrew Dupont)
+
 * Null out references to elements in cache on page unload. Need this in addition to the Event#stopObserving calls to clean up memory leaks. [#425 state:resolved] (ykphuah, mr_justin, Andrew Dupont)
 
-* Ensure `toString` and `valueOf` properties are copied to a subclass only when necessary in IE6. [@382 state:resolved] (Samuel Lebeau)
+* Ensure `toString` and `valueOf` properties are copied to a subclass only when necessary in IE6. [#382 state:resolved] (Samuel Lebeau)
 
 * Make sure `getAttribute` is used without flag when accessing the "type" attribute of an iframe (IE throws error otherwise). [#118 state:resolved] (Zekid, kangax)
 

src/dom/selector.js

@@ -18,23 +18,50 @@ var Selector = Class.create({
     
   },
   
-  shouldUseXPath: function() {
-    if (!Prototype.BrowserFeatures.XPath) return false;
+  shouldUseXPath: (function() {
     
-    var e = this.expression;
-
-    // Safari 3 chokes on :*-of-type and :empty
-    if (Prototype.Browser.WebKit && 
-     (e.include("-of-type") || e.include(":empty")))
-      return false;
+    // Some versions of Opera 9.x produce incorrect results when using XPath
+    // with descendant combinators.
+    // see: http://opera.remcol.ath.cx/bugs/index.php?action=bug&id=652
+    var IS_DESCENDANT_SELECTOR_BUGGY = (function(){
+      var isBuggy = false;
+      if (document.evaluate && window.XPathResult) {
+        var el = document.createElement('div');
+        el.innerHTML = '<ul><li></li></ul><div><ul><li></li></ul></div>';
+        
+        var xpath = ".//*[local-name()='ul' or local-name()='UL']" +
+          "//*[local-name()='li' or local-name()='LI']";
+          
+        var result = document.evaluate(xpath, el, null, 
+          XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
+          
+        isBuggy = (result.snapshotLength !== 2);
+        el = null;
+      }
+      return isBuggy;
+    })();
     
-    // XPath can't do namespaced attributes, nor can it read
-    // the "checked" property from DOM nodes
-    if ((/(\[[\w-]*?:|:checked)/).test(e))
-      return false;
+    return function() {      
+      if (!Prototype.BrowserFeatures.XPath) return false;
 
-    return true;
-  },
+      var e = this.expression;
+
+      // Safari 3 chokes on :*-of-type and :empty
+      if (Prototype.Browser.WebKit && 
+       (e.include("-of-type") || e.include(":empty")))
+        return false;
+
+      // XPath can't do namespaced attributes, nor can it read
+      // the "checked" property from DOM nodes
+      if ((/(\[[\w-]*?:|:checked)/).test(e))
+        return false;
+
+      if (IS_DESCENDANT_SELECTOR_BUGGY) return false;
+
+      return true;
+    }
+    
+  })(),
   
   shouldUseSelectorsAPI: function() {
     if (!Prototype.BrowserFeatures.SelectorsAPI) return false;

test/unit/selector_test.js

@@ -88,7 +88,7 @@ new Test.Unit.Runner({
   },
   
   testSelectorWithAttributeContainingDash: function() {
-    this.assertEnumEqual([$('attr_with_dash')], $$('[foo-bar]'));
+    this.assertEnumEqual([$('attr_with_dash')], $$('[foo-bar]'), "attribute with hyphen");
   },                                                            
   
   testSelectorWithUniversalAndHyphenTokenizedAttributeValue: function() {
@@ -392,5 +392,13 @@ new Test.Unit.Runner({
     var b = $('dupContainer').down('#dupL4');
     
     this.assertEqual(a, b);
+  },
+  
+  testDescendantSelectorBuggy: function() {
+    var el = document.createElement('div');
+    el.innerHTML = '<ul><li></li></ul><div><ul><li></li></ul></div>';
+    document.body.appendChild(el);
+    this.assertEqual(2, $(el).select('ul li').length);
+    document.body.removeChild(el);
   }
 });