Comment # 4 on bug 1202786 from Georg Pfuetzenreuter

Interesting. It indeed works with your dummy example on Tumbleweed (not on
15.4, but that seems to be a different issue). With my python-limnoria package
however:

%pre -f %{_sourcedir}/%{name}.pre

RPM build errors:
    Could not open Prein file
/home/abuild/rpmbuild/BUILD/home/abuild/rpmbuild/SOURCES/Limnoria-20220814/home/abuild/rpmbuild/SOURCES/python-limnoria.pre:
No such file or directory

I suppose that's some peculiarity with my package and out of scope of this bug
then.