Re: [PATCH v2 3/3] upload-pack: allow configuring a missing-action

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 3, 2024, 17:29 UTC
Message-ID: <xmqq1q5e3pf0.fsf@gitster.g>
In-Reply-To: <CAP8UFD0aiBY27_8HqjyMtze1ZcME2gZVTMyB=botNErmu_CJDg@mail.gmail.com>

Christian Couder <christian.couder@gmail.com> writes:

> Alternatively, if C would pass a new option called for example
> --known-promisor=X on top of all other options, then that could be Ok
> too?

Why do you need a new option "--known-promisor=X" in the first place? Doesn't it known by the repository already and you do not have to bother the end user to supply it from the command line, no?

In any case, a protocol extension that lets S tell C that S wants C to fetch missing objects from X (which means that if C knows about X in its ".git/config" then there is no need for end-user interaction at all), or a protocol extension that C tells S that C is willing to see objects available from X omitted when S does not have them (again, this could be done by looking at ".git/config" at C, but there may be security implications???). Either would work OK and I offhand do not see much preference between the two.

What is important is to ensure that such deliberate omission by S is safe and acceptable by C.

Thanks.

[Footnote]

By the way, I briefly wondered: would "X" that is valid for "C" be always valid for "S" these days?

I as "S" may prefer you as "C" to go ssh://gitlab.com/x.git but you may only be able to go https://gitlab.com/x.git for networking reasons. Silly situation like that may make communicating "X" between "S" and "C" a bit harder than we would like. Of course this is not a high priority issue as the user with such networking need are probably already using url.X.insteadof to rewrite the submodule paths recommended in .gitmodules after they clone a superproject, iow, even if it were a problem, it is a solved one.

So, in short, yes, exchanging the known promisor "X" between "S" and "C", regardless of which side speaks first, as long as the negotiation makes sure both sides agree, would be a good direction to go, I would think.