Subject: Re: [PATCH] receive-pack: optionally deny case-clone refs

From: Junio C Hamano <[email-masked]>
Date: Tue, 03 Jun 2014 15:13:31 -0700

David Turner <[email-masked]> writes:

> I would be happy to add "case-clone" to the glossary -- would that be OK
> with you?  I do not immediately think of the better term.

Somehow "case-clone" sounds strange, though X-<.

>> (Mental note to the reviewer himself) This returns true iff there is
>> an existing ref whose name is only different in case, and cause
>> for-each-ref to return early with true.  In a sane case of not
>> receiving problematic refs, this will have to iterate over all the
>> existing refnames.  Wonder if there are better ways to optimize this
>> in a repository with hundreds or thousands of refs, which is not all
>> that uncommon.
>
> My expectation is that on average a push will involve a small number of
> refs -- usually exactly one.

It does not matter that _you_ push only one, because the number of
existing refs at the receiving end is what determines how many times
the for-each-ref loop spins, no?

> Yes, but it's harder to test on case-insensitive filesystems because we
> cannot have coexisting local case-clone branches.

You do not have to (and you should not) do "git checkout -b" to
create various local branches in the first place.  For example:

	git send-pack ./victim HEAD^1:refs/heads/caseclone &&
	test_must_fail git send-pack ./victim HEAD:refs/heads/CaseClone

would let you push the parent of the current tip to caseclone and
then attempt to push the current tip to CaseClone.  If the receiving
end could incorrectly fast-forwards caseclone, you found a bug ;-)