I recently raised a pull request on zfec for converting its python packaging from pure setup.py to pbr based. Today I got review from Brian Warner and one of the issue mentioned was python setup.py --version is not giving same output as previous version of setup.py.
Previous version used versioneer which extracts version information needed from VCS tags. Versioneer also provides flexibility of specifying type of VCS used, style of version, tag prefix (for VCS) etc. pbr also does extract version information from git tag but it expects git tag to be of format tags/refs/x.y.z format but zfec used a zfec- prefix to tag (example zfec-1.4.24) and pbr does not process this. End result, I get a version in format 0.0.devNN where NN is number of commits in the repository from its inception.
Me and Brian spent few hours trying to figure out a way to tell pbr that we would like to override version information it auto deduces, but there was none other than putting version string in PBR_VERSION environment variable. That documentation was contributed by me 3 years back to pbr project.
So finally I used versioneer to create a version string and put it in the environment variable PBR_VERSION.
import os
import versioneer
os.environ['PBR_VERSION'] = versioneer.get_version()
...
setup(
setup_requires=['pbr'],
pbr=True,
ext_modules=extensions
)
And added below snippet to setup.cfg which is how versioneer can be configured with various information including tag prefixes.
[versioneer]
VCS = git
style = pep440
versionfile_source = zfec/_version.py
versionfile_build = zfec/_version.py
tag_prefix = zfec-
parentdir_prefix = zfec-
Though this work around gets the work done, it does not feel correct to set environment variable to change the logic of other part of same program. If you guys know the better way do let me know!. Also probably I should consider filing an feature request against pbr to provide a way to pass tag prefix for version calculation logic.