How does Validate Input/ Validate output works in invoke service?

I tried calling getFile service in try block and made the Validate input property of the getFile invoke step as true. the input of the service is filename. In the catch block I placed getLastError

When I run the service without passing the filename input, it is not returning any error.

Why is this happening?

Did I implement it wrong way? what is the correct implementation of validate input/output at invoke step level?

Are there any messages in the server log or error.log?

Did you try to debug the service and see whats happening?

Regards,
Holger

Looks to me like a bug. Can you raise it to SAG support to confirm? I did try with latest IS fix levels of 9.12, I am able to reproduce it.

I tried implementing this in 10.0

There are no server or error logs, the service is exiting without any error.