setup.py with pbr attempts to do git operations in tarball

[Adam Young]

While building out of git tree, for example in an rpm spec file:

%{__python} setup.py build

will error out with
error in setup command: Error parsing /home/ayoung/rpmbuild/BUILD/keystone-2014.2.3b/setup.cfg: Exception: Versioning for this project requires either an sdist tarball, or access to an upstream git repository. Are you sure that git is installed?

This is true even if the tarball was created with sdist.

The correct logic should be: if the source is not in a git repository and the PKG-INFO has been created, use the existing value.

[Davanum Srinivas (DIMS) (dims-v)]

Adam, which version of pbr do you have?

[Davanum Srinivas (DIMS) (dims-v)]

More information from Adam on his blog post:
http://adam.younglogic.com/2014/09/wherein-our-hero-attempts-to-build-his-own-openstack-keystone-rpms/

[Robert Collins (lifeless)]

So this should only happen if the following is true:
 - its an exported tree (no git history)
 - no egg info is present (which sdist injects for us)

The blog post suggests Adam reached the same conclusion, so I'm not sure that this is a bug: without access to either git history, or explicit version metadata, pbr can't do its job as defined, and an error is appropriate.