Re: [PATCH] clone: check if server supports shallow clones

[Jeff King <peff@peff.net>]

On Wed, Jun 10, 2015 at 02:35:20PM -0400, Mike Edgar wrote:

> When the user passes --depth to git-clone the server's capabilities are
> not currently consulted. The client will send shallow requests even if
> the server does not understand them, and the resulting error may be
> unhelpful to the user. This change pre-emptively checks so git-clone can
> exit with a helpful error if necessary.

This sounds like a good thing to do, but...

> --- a/builtin/clone.c
> +++ b/builtin/clone.c
> @@ -944,6 +944,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
>  
>  	refs = transport_get_remote_refs(transport);
>  
> +	if (option_depth && !is_local && !server_supports("shallow"))
> +		die(_("Server does not support shallow clients"));
> +

It feels a little weird to be checking the option here in cmd_clone.
The transport layer knows we have specified a depth, so it seems like a
more natural place for it (or possibly even lower, in the actual
git-protocol code).

That being said, I think the current capabilities handling is a bit
messy and crosses module boundaries freely. So I would not be surprised
if this is the most reasonable place to put it. But it does make me
wonder whether "git fetch --depth=..." needs the same treatment.

I see that do_fetch_pack checks server_supports("shallow"). Is that
enough to cover all fetch cases? And if it is, why does it not cover the
matching clone cases?

-Peff