One more thing.... reference image of workflow....
The first filter after the parse is do not pass if Quantity is null... it passes no records to the rest of the snipped ...and then hits my count / zero filter ....yet it still hits the formula with no records and errors causing my app to fail.
without getting into detailed solution to your problem. How about this quick idea? You can create a marco that has two branchs for the input stream and then a Union at the end. Put the two branches in separate Tool Containers. Pass a count of records into the macro as a parameter. If the count is Zero disable the first container, if not disable the second container. reach out of you have additional questions or can provide detailed data and workflow.
sorry for the quick response change. I did an additional test and the workflow still runs if you only have the first container and no union. with the container turned on it returns the data stream; with the container turned off it returns an empty data stream.