510111 - E4X filter prefers local variable over matching XML node name

Status: RESOLVED INVALID

(Tamarin Graveyard :: Virtual Machine, defect)

Description

[Chris Peyer]

as source:
var xml:XML = <items>
  <item id="item1" type="item1_type" />
  <item id="item2" type="item2_type">
<item id="item3" type="item3_type" />
  </item>
</items>;



function getItemTypeNotWorking(item:String):void {
    trace("test1 = ", xml..*.(name() == "item" && @id == item).@type);
}

function getItemTypeWorking(itemID:String):void {
    trace("test2 = ", xml..*.(name() == "item" && @id == itemID).@type);
}

getItemTypeNotWorking("item2");
getItemTypeWorking("item2");



Steps to reproduce:
1. filter an XML with a E4X filter, example: xml..*.(name() == "item" && @id == "item1").@type
2. encapsulate the filter in a function with a variable name identical to the node

sources and explanation there:
http://www.soundstep.com/blog/2008/11/12/flash-cs4-bug-with-xml-e4x-filters/

Actual Results:
value not returned by the filter
 
Expected Results:
value returned
 
Workaround (if any):
use a different variable name 

This bug transferred from: http://bugs.adobe.com/jira/browse/ASC-3787

Comment 1

[Dan Smith]

Jeff, is the behavior consistent with the E4X specification?

Comment 2

[Jeff Dyer]

Actually what is going on here is @id == item is comparing the current value of @id and item, both of which are in the dynamic scope created by the filter expression. In other words the parameter 'item' is being shadowed by the XML element 'item'. This is per spec. 

(It is a know language bug that there is not way to resolve the scope of name in a filter expression to an outer scope.)

Resolving as NAB.