The repoman code already has the option to bypass the no artifacts test without failing by adding the following code:
--option=main.on_empty_source=<option>

You can use one of the options below:
1. ignore (The ignore won't show any warning message and won't fail on raise Exception).
2. warn (The warn will show a warning message without failing on raise Exception)
3. fail (The fail will show a warning message and fail on raise Exception ==> default)