AttributeError: 'NoneType' object has no attribute 'groups' if tag has the wrong syntax

[plijnzaad]

(I created this issue over in the setuptools repo (see https://github.com/pypa/setuptools/issues/2326 ) but I realize that it should actually be here, sorry)

I happened to have a git tag of the wrong syntax, namely 2.0.0-alpha.5-PMC, leading to the above error. It was very difficult to track down for a lowly end-user of a package (atropos) that uses it, and which I forked in order to fix a few things. I did not know that tags were needed, let alone be of a very specific shape (and 2.0.0-alpha.5-PMC is not that extreme, right?) .

I have appended the stdout and stderr before git tag --delete 2.0.0-alpha.5-PMC (std*-bad.txt) and after deleting the offending tag (std*-good.txt) (done with export SETUPTOOLS_SCM_DEBUG=verbose)

stdout-bad.txt
stderr-bad.txt

stdout-good.txt
stderr-good.txt

I tried various older versions of setuptools-scm (back to 2.0.0 I recall correctly), all had the same or similar problem. I see several reports of people having similar trouble so it appears to be a general problem and one that occurs more often. I would love if this were more robust, i.e. I'd much rather have a version string 'unknown' or somesuch than a package that refuses to install ...

Cheers,
P

[plijnzaad]

Actually, where can I find the default syntax rules (with examples) for release tags? I can't figure out why 2.0.0-alpha.5-PMC is not allowed (well, it's not even clear it's not allowed, it just crashes), and alternatively what would be allowed instead (short of trying by trial and error)

[RonnyPfannschmidt]

https://github.com/pypa/setuptools_scm/blob/master/src/setuptools_scm/config.py#L9 has the default stuff

for something thats clearly not a valid python package version number we should have a better error

[plijnzaad]

Thanks for digging this up! However my offending tag 2.0.0-alpha.5-PMC matches this regexp, so something else is wrong. And it would be nice if the tag syntax were documented somewhere more prominent :-)

[RonnyPfannschmidt]

@plijnzaad thanks for calling me out, now that i'm looking a closer look i'm seeing what i missed

https://github.com/pypa/setuptools_scm/blob/1c8bb50e90520a39279f213706ad69b4f180fea1/src/setuptools_scm/version.py#L214-L235

the default implementation for version bumping is too simplicistic and completely falls appart with propperly finding the point where to add a number

setuptools_scm should warn/error in a more comprehensible way when the version that is still "accepted" is not actually handleable by the bump helper itself

if you have a tool for determining the next version you can hook it in