Re: [PATCH] upload-pack: reject shallow requests that would return nothing

[Duy Nguyen <pclouds@gmail.com>]

On Mon, May 28, 2018 at 7:55 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
>> To avoid this, if rev-list returns nothing, we abort the clone/fetch.
>> The user could adjust their request (e.g. --shallow-since further back
>> in the past) and retry.
>
> Yeah, that makes sense.
>
>> Another possible option for this case is to fall back to a default
>> depth (like depth 1). But I don't like too much magic that way because
>> we may return something unexpected to the user.
>
> I agree that it would be a horrible fallback.  I actually am
> wondering if we should just silently return no objects without even
> telling the user there is something unexpected happening.  After
> all, the user may well be expecting with --shallow-since that is too
> recent that the fetch may not result in pulling anything new, and
> giving a "die" message, which now needs to be distinguished from
> other forms of die's like network connectivity or auth failures, is
> not all that helpful.

An empty fetch is probably ok (though I would need to double check if
anything bad would happen or git-fetch would give some helpful
suggestion). git-clone on the other hand should actually clean this up
with a good advice. I'll need to check and come back with v2 later.
-- 
Duy