xml.js crashes on invalid keyrefs

[CruzR]

Here's a minimal test case:

Schema:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="test">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="foo">
        <xs:complexType>
          <xs:attribute name="index" type="xs:int"/>
        </xs:complexType>
      </xs:element>
      <xs:element name="bar">
        <xs:complexType>
          <xs:attribute name="foo" type="xs:int"/>
        </xs:complexType>
      </xs:element>
    </xs:sequence>
  </xs:complexType>
  <xs:key name="fooIndex">
    <xs:selector xpath="./foo"/>
    <xs:field xpath="@index"/>
  </xs:key>
  <xs:keyref name="indexRef" refer="fooIndex">
    <xs:selector xpath="./bar"/>
    <xs:field xpath="@foo"/>
  </xs:keyref>
</xs:element>
</xs:schema>

XML:

<test>
<foo index="1"/>
<bar foo="2"/>
</test>

When I try to validate this on Firefox 19.0.2 on Windows XP, the console is cleared and the output switches to Validating..., but nothing ever happens (although the UI still works). When I do the same with Firebug enabled, the script seems to get into an infinite loop. The expected behaviour is:

$ xmllint --noout --schema test.xsd test.xml
test.xml:3: Schemas validity error : Element 'bar': No match found for key-sequence ['2'] of keyref 'indexRef'.
test.xml fails to validate