[FIXED HUDSON-7475] maintain ancestors if possible when forwarding to error page,

so nav links at top work properly


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@35270 71c3de6d-444a-0410-be80-ed276b4c234a

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

 /*
  * The MIT License
  *
- * Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
+ * Copyright (c) 2004-2010, Sun Microsystems, Inc., Kohsuke Kawaguchi
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -57,6 +57,9 @@ public class Failure extends RuntimeException implements HttpResponse {
         req.setAttribute("message",getMessage());
         if(pre)
             req.setAttribute("pre",true);
-        rsp.forward( node instanceof AbstractModelObject ? node : Hudson.getInstance() ,"error",req);
+        if (node instanceof AbstractItem) // Maintain ancestors
+            rsp.forward(Hudson.getInstance(), ((AbstractItem)node).getUrl() + "error", req);
+        else
+            rsp.forward(node instanceof AbstractModelObject ? node : Hudson.getInstance() ,"error", req);
     }
 }