[Xsltforms-support] serialize() fails on empty nodeset: workaround and proposed fix

[Leigh L K. Jr <lei...@xe...>]

Calling the XPath extension function serialize(x) if x is an empty nodeset.
In Firefox, it fails with a popup about a component failure.

For example:
<group ref="/path/to/parent">
<output value="serialize(x)" />
</group>

This will fail if x doesn't exist, or even if parent doesn't exist.

The only workaround I've found is a an instance with an empty element:
<instance id="empty"><data xmlns=""><empty /></data></instance>
<group ref="/path/to/parent">
<output value="serialize(instance('empty')/empty | x)" />
</group>

Here's a proposed change to the serialize function which makes serialize 
return an empty string if there is no nodeset.

Changes from xsltforms-dataisland-478.zip

===================================================================
--- xsltforms.js    (xsltforms-dataisland-478)
+++ xsltforms.js    (working copy)

@@ -9241,6 +9241,7 @@
              if (arguments.length == 0) {
                  throw XPathCoreFunctionsExceptions.serializeNoContext;
              }
+            if (!nodeSet[0]) return "";
              return Core.saveXML(nodeSet[0]);
          } ),