Yes, gitdb is part of the requirements https://gitpython.readthedocs.io/en/stable/intro.html#requirements

Those are GitPython's requirements, though, not my requirements...
For example, gitdb2 depends on smmap, but GitPython doesn't have that in its requirements.txt.

Thanks for posting! I believe this is indeed an issue, and it's worth fixing for better usability and less surprises.
Historically, GitDB was meant as standalone low-level library anyone could use, but practically it's only used by GitPython. And if memory serves, at some point I did my best to reduce the dependency by using the git <command> backend instead. However, depending on the method, GitDB is still used as indicated here.

I believe everyone would benefit by removing or merging GitDB into GitPython for good, and PRs are very welcome.

That sounds like a big task... In the meantime, maybe something like this could suffice:

try:
    gitdb.op()
except gitdb.exc.ODBError as exc:
    raise git.exc.GitDBError from exc

Actually though, I just realized that GitPython (not GitDB) is raising gitdb.exc.BadName:

So, maybe more like:

class BadName(git.exc.GitError, gitdb.exc.BadName):
    pass

raise BadName(name)

edit: FWIW, my workaround is to catch git.exc.BadName directly which works because GitPython imports gitdb exceptions:

@tucked Wow, fantastic write up! I would be so happy if this could be fixed for everyone with what seems like a small PR. (Still catching up on emails, maybe the PR is already there)