The new regex does not match this valid unnumbered source and patch syntax:

Source: something.tar.gz
Patch: another.patch

Please replace \d+ with ḑ* to fix that.

@oturpe I tried (yesterday) to find the authoritative answer for the regular expression in manuals and rpm sources. I didn't see the version without the number at Source/Patch. Do you have some material that supports the opposite?

Additionally, Source/Path were always with capital. I kept the original re.IGNORECASE
Even the \s* right before the colon might be possibly omitted.

Unfortunately, I am not aware of an authoritative source either. I learned about this syntax from this Fedora packaging thread. And indeed, all examples in Fedora Packaging Guidelines actually use this form. For example, see Patch Guidelines.

Testing with RPM 4.20 (and with no reason to believe this has changed recently, or ever), all tags are read in case insensitive manner. So re.IGNORECASE is appropriate here.

This would probably be worth a documentation issue for rpm.org. Spec File format page does not do a good job explaining the options.

@oturpe, you are right. I verified the parsing with rpmbuild. Unnumbered keywords (as well as case-insensitive variants) are accepted. I will consider rpmbuild as authoritative enough. Thanks.

Rpm.org documentation issue: rpm#3384