When I made a new port devel/py-jschema_to_python[SEE ALSO], I found a issue to try to git log the entire ports tree on build by devel/py-pbr like PR#258891. But I don't fix it and don't have any idea to fix this issue. So I only report it.
As I said in bug #264362 comment #3, the build should use either the sdist (from PyPI) or a complete git clone.
Thank you, I'll use CHEESESHOP magic macro MASTERSITES! That's cool!