Error in `repo.active_branch` if branch is in DETACHED HEAD state

[cgi1]

Error in repo.active_branch if branch is in DETACHED HEAD state:

{TypeError}HEAD is a detached symbolic reference as it points to '0fa1f2a7d9dd9fb63fa775d2d97ad72f56f1d819'

The branch is None in def _get_ref_info(cls, repo, ref_path): because of

# its a commit
        if repo.re_hexsha_only.match(tokens[0]):
            return (tokens[0], None)

def active_branch(self) could return HEAD-{commit-hash} instead like:

    try:
        active_branch = repo.active_branch
    except:
        active_branch = 'DETACHED_' + repo.head.object.hexsha

[cgi1]

Looks similar to #629

[Byron]

I am not sure it would be right to return a commit instead. The function is called active_branch, and I would assume people expect it to return a branch, never a commit. If HEAD is detached, there is no branch to return.
What do you think?

[cgi1]

Hm good point, I don´t have a pefect answer.. To return no branch seems to be ok.

[Byron]

I think returning no branch would break existing code which expects an exception. On the other hand, the exception is not documented, so in a way it's running under the radar anyway.

Maybe it could be adjusted to return None if there is no active branch instead, which would make the calling code a little less cumbersome and safer, as it could start to expect that.

Would you like to contribute a respective PR?

[peterbe]

I stumbled on this too. With submodules.
My solution wasn't to try to rely on a try: except: ... but I made it always check out at least some branch first before it started switching to the branch I ultimately wanted to. I.e. always start with repo.heads[config["master_branch"]].checkout()

[stas00]

3 years later and this is still a problem :(

[Byron]

I think returning no branch would break existing code which expects an exception. On the other hand, the exception is not documented, so in a way it's running under the radar anyway.

Maybe it could be adjusted to return None if there is no active branch instead, which would make the calling code a little less cumbersome and safer, as it could start to expect that.

Would you like to contribute a respective PR?

I believe this comment still holds.