Return non zero code on failure

src/nextflow_file.py

@@ -91,13 +91,20 @@ class Nextflow_File(Nextflow_Building_Blocks):
         if(self.first_file):
             return self.output_dir
         else:
-            return self.origin.get_output_dir()
+            if(self.origin==None):
+                return self.output_dir 
+            else:
+                return self.origin.get_output_dir()
         
     def get_display_info(self):
         if (self.first_file):
             return self.display_info
         else:
-            return self.origin.get_display_info()
+            if(self.origin==None):
+                return self.display_info 
+            else:
+                return self.origin.get_display_info()
+                
 
 
     def set_name(self):