pq11396.txt EXCEPTION IS NOT RESUMABLE ERROR IN "WHENEXCEPTIONDO: 
               ACOMPLETIONBLOCK [ SIGNAL RESUMEBLOCK: NIL]"

"whenExceptionDo: aCompletionBlock [ signal resumeBlock: nil]" is processed 
before any exception handler. This is a completion block not an exception handler 
and is equivalent to issuing a signal in an exception handler (a practice that is 
equivalent to throwing an exception in a catch block in Java  or C++).  The  line 
"signal resumeBlock: nil"  makes what would otherwise be a resumeable exception 
non-resumeable.

Workaround: remove resumeBlock: nil from whenExceptionDo:.