Re: git format-patch on empty commit

From: pedro rijo <pedrorijo91@gmail.com>
Date: Jan 11, 2016, 23:47 UTC
Message-ID: <CAPMsMoBp6wdmHsyrG2yMmqSy92R2_Ne-5Kbz-6VFVhLJO_u8mg@mail.gmail.com>
In-Reply-To: <xmqqegdnx1xx.fsf@gitster.mtv.corp.google.com>

To be honest I've been playing a bit with some git features that I've never explored, and was trying to create a fairly simple 'email CLI' upon git send-email and other git commands (just because git can) just for the fun.

Just like you said, there's seems not be a 'clear benefit from such change--it sounds more like a set of "because we could" not "because we need to" changes'. I was more curious to understand this git behavior than asking to fix the bug/implement the feature, so please feel free not to implement this.

Thanks, Pedro Rijo

2016-01-11 21:04 GMT+00:00 Junio C Hamano <gitster@pobox.com>:

Show 47 quoted lines

> Jeff King <peff@peff.net> writes:
>
>> On Mon, Jan 11, 2016 at 02:19:52PM +0000, pedro rijo wrote:
>>
>>> Couldn't find any explanation on git docs on this issue:
>>>
>>> If I create a dummy commit, with some dummy diff, I get a normal patch
>>> when I run
>>>
>>> $ git format-patch -1 -o outgoing/ -p -k
>>>
>>> but if the last commit is an empty commit, generated by
>>>
>>> $ git commit --allow-empty "Some commit message"
>>>
>>> then the output of the format patch will be an empty patch. If the
>>> first case produces something like this:
>>
>> I'm not sure if this is a bug or not.
>>
>> In the beginning, git's revision-traversal machinery generally does not
>> show commits which have no diff. Over the years, commands like "git log"
>> learned to set the "always_show_header" option to show even empty
>> commits. But format-patch never did.
>
> The patch based workflow support is geared towards helping the
> recipient of the patches a lot more than the contributors, and to
> prevent mistakes while applying the patches, "am" would stop when it
> sees such an empty e-mail as you saw (in the later part of message I
> am not quoting).  After all, a "format-patch" output that does not
> have any patch would be indistinguishable from discussion e-mail
> messages and the recipient would not want to end up with no-op
> commits that record such messages.
>
> So I think skipping no-op commit from the output was done pretty
> much deliberately and it is definitely not a bug.  I however do not
> think it is incorrect to say that it is a lack of feature that
> nobody so far found necessary or beneficial.
>
> I would not refuse to consider adding a new option to "format-patch"
> to emit such a no-op message, and add a "having no patch is OK, just
> record a no-op commit" option to "am", though.  But I do not see a
> clear benefit from such change--it sounds more like a set of
> "because we could" not "because we need to" changes to me.
>
> Thanks.
>

-- 
Obrigado,

Pedro Rijo