Re: [PATCH v2 0/2] Update sha1dc from upstream & optionally make it a submodule

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: May 25, 2017, 10:44 UTC
Message-ID: <CACBZZX5Aa9cQngCgMVP2kb8Jnk_V7coK-f5J6jMOhn=AWCrXzQ@mail.gmail.com>
In-Reply-To: <xmqqo9ujk9ii.fsf@gitster.mtv.corp.google.com>

On Tue, May 23, 2017 at 3:06 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 11 quoted lines

> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>
>> Seems like it would be useful to have a way to ex-post-facto say "past
>> history should use these URLs". i.e. if all git.git mirrors go down
>> and we have to re-host, then you can just clone git.git and off you
>> go, but the same isn't true of past submodule urls, or is it?
>
> I do not know how heavily you are used to use submodules, but I
> think submodule's URL is copied to the config of the superproject,
> and that URL is what will be used from there on, so "past history or
> future history will use that URL" is already the case, no?

I haven't used them much, just starting to get familiar with them now again.

I thought given your "if it is ever rewound away in the upstream history..." that if we e.g. pegged upstream to that github URL now that if that got rewound, anyone working with git.git in the future would be in for some pain if they needed to check out and test old tags.

But from what you're saying here that seems like a non-issue, i.e. in such a scenario we'd just mirror the original repo[1], change the URL in git.git to that, and then anyone could easily use older history since it would be pointing to the new mirror.

I.e. in the spirit of my last reply, this seems like deviating from the default workflow around submodules out of concern for an extremely unlikely scenario, which, if it happened, would be easily mitigated for both past & future git.git history.

1. Or likely just ask upstream kindly to push a tag with the old history.