Forward porting singleton warn vs error for Cron.

docs/changelog/7.x.x.txt

@@ -4,8 +4,8 @@
  - fixed #4173: fieldnames in profilefields can contain spaces
  - fixed #8811: Bug Tracker: Formatting is bad for the resolution form.
  - fixed #9235: Image Bug in rich text editor.
- - fixed #9219: Thingy After Save Search This Thing not showing all rows (SDH
-   Consulting Group)
+ - fixed #9219: Thingy After Save Search This Thing not showing all rows (SDH Consulting Group)
+ - fixed #9231: Singleton workflows should not report an error when an attempt is made to run them again
 
 7.6.5
  - security: A problem was discovered and fixed in which users could email executable attachments to a collaboration system and then when viewed online, could execute them. 

lib/WebGUI/Operation/Cron.pm

@@ -291,6 +291,13 @@ sub www_runCronJob {
 			priority    => $task->get("priority"),
                     });
                 if ( !$instance ) {
+                    if ($session->stow->get('singletonWorkflowClash')) {
+                        $session->errorHandler->warn( 
+                            "Could not create workflow instance for workflowId '" . $task->get( "workflowId" )
+                            . "': It is a singleton workflow and is still running from the last invocation."
+                        );
+                        return "done";
+                    }
                     $session->errorHandler->error( 
                         "Could not create workflow instance for workflowId '" . $task->get( "workflowId" )
                         . "': The result was undefined"

lib/WebGUI/Workflow/Instance.pm

@@ -73,8 +73,10 @@ sub create {
         $sql .= ' and parameters IS NULL';
     }
 	my ($count) = $session->db->quickArray($sql,$placeHolders);
+    $session->stow->set('singletonWorkflowClash', 0);
     if ($isSingleton && $count) {
         $session->log->info("An instance of singleton workflow $properties->{workflowId} already exists, not creating a new one");
+        $session->stow->set('singletonWorkflowClash', 1);
         return undef
     }