On inspect-robots 0.59.0, git rev-parse HEAD succeeding and git status --porcelain failing still records the bare SHA. That is the same string as a clean checkout. #473 is the report; #475 is in v0.60.0.
I ran _git_commit from the PyPI 0.59.0 and 0.60.0 wheels in a toy repo on git 2.53.0. Clean returned the SHA. A modified tracked file got -dirty. After I truncated .git/index, status exited 128 (fatal: .git/index: index file smaller than expected). 0.59.0 kept the SHA. 0.60.0 returned None, which is also what a directory with no git returns.
PyPI latest is 0.60.0. 0.59.0 is still listed and not yanked.