Re: [PATCH] fetch: add config to avoid fetching every branch in shallow repo

[Junio C Hamano <gitster@pobox.com>]

"D. Ben Knoble" <ben.knoble@gmail.com> writes:

>>     $ git fetch second main:refs/remotes/second/main
>
> I've wanted something similar for notes, so allow me to interject from
> the sidelines: it would be even nicer to still have the ability to map
> fetches (so that "git fetch second main" did the right thing, creating

The thing is, the command line

    $ git fetch second main

has been used for the past 20 years as a "single-shot fetch" syntax
that expresses that the user does not intend to keep interacting
with the same 'main' branch or even the same 'second' repository,
and for the "single-shot fetch", it is absolutely the wrong thing to
create a remote-tracking branch.

It would be even worse if we created a remote 'second' and
remote-tracking branch 'refs/remotes/second/main' when you ran

    $ git fetch https://ho.st/second main

Having said that, I suspect that the fact that you have the
shorthand 'second' (i.e., you have "[remote "second"] url = ..."
defined) may be a good enough sign that you expect to keep
interacting with that repository, and some people might appreciate
it if

    $ git fetch second main

created a remote-tracking branch "refs/remotes/second/main"
automatically.

But we cannot suddenly start doing so without breaking people's
expectations, and without a good transition plan.  We need at least
an escape hatch for users to say "No, this is a single-shot fetch;
do not write the object anywhere other than FETCH_HEAD as we have
always done".