Hi Olivier,
You are very right, and all this has been rewritten and fixed in my devel branch. Unfortunately the F33 change process ate all the time I had to spend on the subject on the summer, and now personal problems and covid consequences are preventing me from finishing things.
You can see a working POC here https://copr.fedorainfracloud.org/coprs/nim/go-modules/packages/
(at the time I also successfully tested multi-module packaging with different versions from a single spec)
If you have some cycles to spend on the subject you can try to un-stick
https://src.fedoraproject.org/rpms/redhat-rpm-config/pull-request/109
because I don’t have the time right now to beg people to look at it again. Besides after months of the same unchanged code sitting in the review queue I’m franckly sick of it all
Regards,