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

> 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.