Re: [PATCH] fetch: allow adding a filter after initial clone.

From: Junio C Hamano <gitster@pobox.com>
Date: May 13, 2020, 22:18 UTC
Message-ID: <xmqqsgg3qy1v.fsf@gitster.c.googlers.com>
In-Reply-To: <CAOhzdui-4KeOit74fTy=3YxSncHGZzy+cE+6njyjHPyJ8xFpMA@mail.gmail.com>

Xin Li <delphij@google.com> writes:

Show 14 quoted lines

> The proposed change would allow converting an existing git clone to
> use partial clones.  For example:
>
> $ git clone --depth=1 https://android.googlesource.com/platform/bionic .
> $ git fetch --unshallow --filter=blob:none origin
>
> Previously, to allow this one would have to do the following manually
> first; the existing code would handle the rest gracefully:
>
> $ git config core.repositoryFormatVersion 1
> $ git config extensions.partialClone origin
>
> And the proposed change would have git do it for the user
> automatically, the existing workflow remains otherwise unchanged.

Actually, do we even know, when we "upgrade" the repository with the patch, that the 'origin' supports the required protocol extensions like on-demand fetching of objects?

At "git clone" time, "git clone --filter=..." against a server that is not prepared to serve as a lazy clone's backup remote would fail, so we will never write extensions.partialClone=origin when origin cannot serve as such.

But writing these config you suggest to "do manually" is already not a safe thing to do, without making sure it is supported, no? It does not sound like a good idea to do an unsafe thing for the user automatically.

Added a few folks on Cc: list, who know and care more about partial clones than I do for input.

Thanks.