Subject: Re: [Feature Request] Allow batch removal of remotes with 'git remote remove'

From: Junio C Hamano <[email-masked]>
Date: Wed, 22 Jan 2025 08:23:09 -0800

Jeff King <[email-masked]> writes:

> On Wed, Jan 22, 2025 at 02:24:38AM +0000, brian m. carlson wrote:
>
>> Because `git remote remove` will remove remote-tracking branches and
>> their reflogs, we typically will want to do that all at once in a single
>> ref transaction, and hence in one command.  Not doing so performs very
>> poorly (as does, notably `git remote rename`[0]) when all of the refs are
>> packed.  If you have a large number of remotes to delete and a large
>> number of total refs, this will perform really badly indeed, since the
>> operation of rewriting the packed-refs file becomes quadratic.
>> 
>> The removal of the remote-tracking branches is also the reason that
>> editing the config isn't sufficient, either.
>
> I think the config update is probably quadratic, too (in the number of
> remotes). Each one is going to rewrite the whole config file, minus its
> matching section. But a "remove" operation that took multiple remotes
> could do it all in a single pass.
>
> If somebody does implement "remote remove" that takes multiple names, I
> hope they'll refactor to do all of the operations in a single pass, and
> not just loop on builtin/remote.c:rm() internally.
>
> Probably git-config could stand to learn similar tricks, too. There is
> "--remove-section", but I don't think you can pass multiple sections
> (and it's likewise quadratic).

Thanks for bringing up the performance aspect and where the problem
lies in the current implementation.