Re: [PATCH v4 0/1] receive-pack: optionally deny case clone refs

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 13, 2014, 21:25 UTC
Message-ID: <xmqqfvj81oym.fsf@gitster.dls.corp.google.com>
In-Reply-To: <CAL=YDW=xn0OG5vu=9fnP0nycKV0F9bDJLrkYiwmL9P9q79LJSw@mail.gmail.com>

Ronnie Sahlberg <sahlberg@google.com> writes:

> It gets even more hairy :
> If the server has A/a and a/b and you clone it it becomes A/a and A/b
> locally. Then you push back to the server and you end up with three
> refs on the server:  A/a A/b and a/b.

That is part of the transition in deployment. David who wants to forbid A/a and a/b mixed in his project will surely correct the situation at the server end so "somebody fetches A/a and a/b and ends up with A/a and A/b" will not happen. They will fetch A/a and A/b.

If a user is with an older Git and he has his own a/c, fetching A/a and A/b from a corrected central repository will still give the user a/a and a/b, but then pushing it back will be forbidden. The user's repository needs to be fixed and installation of Git needs to be updated to the version with an equivalent of David's "optionally deny" feature implemented for the fetching side, so that the user notices the local a/c is bad and not allowed within the context of his project, deletes it and recreates it as A/c before he can fetch A/a and A/b from the central repository.

I agree that the transition may be painful, but as long as the desired semantics is "If you have A/a, you are not allowed to have a/a or a/b", it cannot be avoided---in that sense, I view it as a lower priority issue.

Having said that, it may indicate that the desired semantics above may not be the optimal one. Perhaps the flag might want to be "on this platform, we cannot do case sensitive refs, so pretend as if all refs are lowercase" instead. I suspect that such a flag may allow smoother transition than what has been proposed.

Underlying refs "A/a" and "a/b" can stay as they are in David's central repository, but ref enumeration with the flag enabled will return a/a and a/b, and these are the names that will be fetched by the users. If the user had an existing A/c, then fetching these will still create A/a and A/b locally, but pushing them back will, under that flag enabled, be turned into updates to a/a, a/b, and a/c on the central server side with updated Git.

I dunno.