Re: Strange behaviour of git diff branch1 ... branch2

From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Oct 27, 2012, 13:32 UTC
Message-ID: <CACsJy8BkKRxp9AQW0M0vDSL8Mb16VGSrZ1OnQpwCrERWKVLSyA@mail.gmail.com>
In-Reply-To: <4ecbe65e-4b56-4a49-96c3-1ea8b3f0c473@email.android.com>

On Sat, Oct 27, 2012 at 7:33 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 13 quoted lines

>
>
> Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
>>
>>Notice the --cc in the first line, which is combined diff. Usually
>>combined-diff is between two points and one parent. Though somehow git
>>passes 4 parents down combined-diff.c:show_combined_header, as you can
>>see in the "index" line. I think we should fix rev parsing code as it
>>does not make sense to pass 4 identical parents this way.
>
> The two heads home from HEAD...HEAD the user has on the command line.
>
> The user is getting exactly what she asked; there is nothing to fix.

Is there any use case where HEAD...HEAD (or "..." alone) is actually useful?

I have re-read the git-diff man page and I don't think it explains "git diff foo ... bar" syntax (from a user's point of view, not a git guru's). We could improve the documentation if "git diff foo ... bar" is useful, or reject it with an error to avoid confusion.

-- 
Duy