Re: [PATCH] transport-helper: do not request symbolic refs to remote helpers

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 22, 2015, 22:24 UTC
Message-ID: <xmqqh9visbbt.fsf@gitster.dls.corp.google.com>
In-Reply-To: <20150122221330.GA31912@glandium.org>

Mike Hommey <mh@glandium.org> writes:

Show 15 quoted lines

> On Thu, Jan 22, 2015 at 09:52:55AM -0800, Junio C Hamano wrote:
>
>> Does the new code avoid regressions for them and if so how?  That is
>> what was needed in the justification.
>> 
>> For remote helpers that support the 'list' command, asking for a
>> symref and asking for a ref that the symref points at both work OK
>> and behave the same, and hopefully that would be true even when the
>> latter is a symref that points yet another ref, so dereferencing
>> only one level on our end when making a request, instead of letting
>> the remote side dereference, is not likely to cause regression.
>
> If I'm not mistaken, in that case with more than one level of symref,
> nothing would break more than it already is, the bug would only not be
> fixed for that case.

Yes, I think we are in agreement.  All is well.

> That said, does this theoretical double indirection actually
> happen in the wild?

With the proliferation of Git-using people and third-party tools that work with Git, I think the value of asking that question has diminished. People do strange things.

And I do not think the patch under discussion does not introduce any new theoretical funnies; it fixes one known case and leaves the rest unfixed, without introducing any new breakage, which is perfectly fine and exactly how we want to make progress. If the unfixed one has a real-world need to be fixed, somebody will raise hand, and if they do not bother to even raise their hands, that is an indication that it is not worth our time worrying about it.

The only thing we need to avoid, while making "one step at a time" progress, is to paint ourselves to a corner we cannot get out of by promising too much --- and I do not think the patch under discussion does that, either.