The following works:
    <at name="cn" rdn="true">
      <expression>slipupi.upi</expression>
    </at>

However, the following, equivalent config, doesn't:
    <at name="cn" rdn="true">
      <expression>return slipupi.upi;</expression>
    </at>

I'll attach more details.


Additional Comments From pigor dated Wed Dec 14 23:27:30 CST 2005 
The penrose.log for the error.

Additional Comments From pigor dated Wed Dec 14 23:41:16 CST 2005 
I tried to debug the problem, and one of the issues seems to be that SearchEngine.searchLocal finds one extra result.

The first one is correct, the second one is empty. I used the following patch to get rid of it:

--- SearchEngine.java.original  2005-12-15 00:38:28.000000000 -0500
+++ SearchEngine.java   2005-12-15 00:38:34.000000000 -0500
@@ -610,7 +610,7 @@
                 parentMapping = partition.getParent(parentMapping);
             }

-            if (parentMapping == null) {
+            if (parentMapping == null && results.size() == 0) {
                 results.add(new AttributeValues());
             }
         }


I don't really know what I'm doing, but the patch seems to  fix the searches when scope=one, and the attributes are a result of an expression. It's still broken for scope=sub.





Additional Comments From endisd dated Thu Jan 26 19:42:05 CST 2006 
There is a problem in the mapping expression. The expression "return slipupi.upi;" will fail if the slipupi object is not present. To avoid the problem, the expression needs to be guarded as follows:

<expression>
  if (slipupi == void || slipupi == null) return null;
  return slipupi.upi;
</expression>

This expression can be shortened as follows:

<variable>slipupi.upi</variable>

If written this way, the code will check the existence of slipupi object first before getting the upi attribute.

The patch did partially fix the problem and has been applied to 0.9.9.



=========================================================
Issue dump from jira
$VAR1 = {
          'priority' => '2',
          'customFieldValues' => [],
          'project' => 'PENROSE',
          'status' => '5',
          'components' => [
                            {}
                          ],
          'attachmentNames' => 'penrose-error-log.txt',
          'reporter' => 'pigor',
          'key' => 'PENROSE-129',
          'assignee' => 'endisd',
          'summary' => 'expressions evaluations doesn't work in 0.9.8',
          'id' => '10351',
          'updated' => '2006-01-26 19:42:05.0',
          'votes' => '0',
          'fixVersions' => [
                           {
                             'releaseDate' => '2006-01-24 00:00:00.0',
                             'sequence' => '9',
                             'name' => 'Penrose-0.9.9',
                             'released' => 'true',
                             'id' => '10040',
                             'archived' => 'false'
                           }
                         ],
          'description' => 'The following works:
    <at name="cn" rdn="true">
      <expression>slipupi.upi</expression>
    </at>

However, the following, equivalent config, doesn't:
    <at name="cn" rdn="true">
      <expression>return slipupi.upi;</expression>
    </at>

I'll attach more details.

',
          'affectsVersions' => [
                               {
                                 'releaseDate' => '2005-12-05 00:00:00.0',
                                 'sequence' => '8',
                                 'name' => 'Penrose-0.9.8',
                                 'released' => 'true',
                                 'id' => '10034',
                                 'archived' => 'false'
                               }
                             ],
          'created' => '2005-12-14 23:24:01.0',
          'environment' => 'linux, penrose 0.9.8, oracle',
          'resolution' => '1',
          'type' => '1'
        };


=========================================================