Non-mandatory file input?

The File Dialog widget input field is mandatory.

However, my code will make use of an input file only if one is provided. If no input file is provided, it will do something different. But since the widget’s input field is mandatory, I am forced to provide an input file, or the workflow will fail.

Can the File Dialog widget input field be made non-mandatory, or alternatively, how can I specify an ‘empty’ default for the corresponding input variable? For example, an empty list if the input variable is of type list[file]?

Or is there a way of doing this using dependent inputs? I could not figure out how.

Dear Heiko,
I will check the possibilities and get back to you