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

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

Xin Li <delphij@google.com> writes:

> 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.