src/Pure/System/session.scala

 
         case Isabelle_Markup.Return_Code(rc) if output.is_exit =>
           if (rc == 0) phase = Session.Inactive
           else phase = Session.Failed
 
-        case _ if output.is_stdout =>
-
         case _ => bad_output(output)
       }
     }
     //}}}
 

           msgs foreach {
             case input: Isabelle_Process.Input =>
               all_messages.event(input)
 
             case output: Isabelle_Process.Output =>
-              handle_output(output)
+              if (output.is_stdout || output.is_stderr) raw_output_messages.event(output)
+              else handle_output(output)
               if (output.is_syslog) syslog_messages.event(output)
-              if (output.is_stdout || output.is_stderr) raw_output_messages.event(output)
               all_messages.event(output)
           }
 
         case change: Change
         if prover.isDefined && global_state().is_assigned(change.previous) =>