Re: format-patch and submodules

[Christopher Dunn <cdunn2001@gmail.com>]

Sorry. I thought empty patches were made to work in other cases.

'git-p4' needs to skip these. Wrong mailing list then.

On Tue, Jun 9, 2015 at 1:52 PM, Jens Lehmann <Jens.Lehmann@web.de> wrote:
> Am 05.06.2015 um 01:20 schrieb Christopher Dunn:
>>
>> (Seen in git versions: 2.1.0 and 1.9.3 et al.)
>>
>> $ git format-patch --stdout X^..X | git apply check -
>> fatal: unrecognized input
>>
>> This fails when the commit consists of nothing but a submodule change
>> (as in 'git add submodule foo'), but it passes when a file change is
>> added to the same commit.
>>
>> There used to be a similar problem for empty commits, but that was
>> fixed around git-1.8:
>>
>>
>> http://stackoverflow.com/questions/20775132/cannot-apply-git-patch-replacing-a-file-with-a-link
>>
>> Now, 'git format-patch' outputs nothing for an empty commit. I suppose
>> that needs to be the behavior also when only submodules are changed,
>> since in that case there is no 'diff' section from 'format-patch'.
>>
>> Use-case: git-p4
>>
>> Of course, we do not plan to add the submodule into Perforce, but we
>> would like this particular command to behave the same whether there
>> are other diffs or not.
>
>
> Hmm, I'm not sure that this is a bug. It looks to me like doing a
>
> $ git format-patch --stdout X^..X | git apply check -
>
> when nothing is changed except submodules and expecting it to work
> is the cause of the problem.
>
> I get the same error when I do:
>
> $git format-patch --stdout master..master | git apply --check -
> fatal: unrecognized input
>
> No submodules involved, just an empty patch.
>
> I assume you want to ignore all submodule changes, so you should
> check if e.g. "git diff --ignore-submodules X^..X" returns anything
> before applying that? (From the command you ran I assume you might
> be able to drop the --ignore-submodules because you already did set
> "diff.ignoreSubmodules" to "all"?)