Re: [PATCH] object-name: explain why <ref>~N fails in a shallow clone

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

Harald Nordgren <haraldnordgren@gmail.com> writes:

>> It is obvious that users would see such a message when they say
>>
>>     $ git show HEAD~20
>>     $ git log HEAD~20..HEAD
>>
>> but would they see the same when
>>
>>     $ git log -20 HEAD
>>     $ git log --since=2.months HEAD
>>
>> and internally HEAD~20 fails to resolve?  Should they see the same
>> hint?
>
> But I think the 'log -20' doesn't even give an error, so where would
> we show that message?

Where?  To their terminal ;-)?

To end users, "git log -20 HEAD" that stops only after showing 2
commits is just as puzzling as, if not more puzzling than, "git show
HEAD~20" that complains "What commit are you talking about?"

At least the latter has an error message that says the commit the
user thought they gave (i.e., HEAD~20) was not interpreted as a
commit, and that might give them enough clue to remind them that
they are the responsible ones for the unexpected beahviour by
initially cloning the repository with a "--depth" option.  On the
other hand, "git log -20" that stops way before they expect it would
does not even give them such a hint.

I thought that helping that case would have much more benefit, hence
my question.