added a defensive check in case plugins fail to compute the changelog. This...

added a defensive check in case plugins fail to compute the changelog. This causes a Jelly error in the following line because the "set" variable is null.

        <j:set var="set" value="${it.changeSet}" />
        <t:summary icon="notepad.gif">
          <j:choose>
            <j:when test="${it.hasChangeSetComputed()}">
-->           <st:include it="${set}" page="digest.jelly" />


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@17299 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/AbstractBuild.java

@@ -400,7 +400,15 @@ public abstract class AbstractBuild<P extends AbstractProject<P,R>,R extends Abs
             scm = new CVSChangeLogParser();
 
         if(changeSet==null) // cached value
-            changeSet = calcChangeSet();
+            try {
+                changeSet = calcChangeSet();
+            } finally {
+                // defensive check. if the calculation fails (such as through an exception),
+                // set a dummy value so that it'll work the next time. the exception will
+                // be still reported, giving the plugin developer an opportunity to fix it.
+                if(changeSet==null)
+                    changeSet=ChangeLogSet.createEmpty(this);
+            }
         return changeSet;
     }