Jeff King <p...@peff.net> writes:
> On Wed, Jan 18, 2017 at 12:57:12PM -0800, Junio C Hamano wrote:
>
>> Jeff King <p...@peff.net> writes:
>>
>> > So I dunno. A sensible rule to me is "iff -p would show a diff header,
>> > then --stat should mention it".
>>
>> True but tricky (you need a better definition of "a diff header").
>>
>> In addition to a new and deleted file, does a file whose executable
>> bit was flipped need mention? If so, then "diff --git" is the diff
>> header in the above. Otherwise "@@ ... @@", iow, "iff -p would show
>> any hunk".
>>
>> I think the patch implements the latter, which I think is sensible.
>
> I would think the former is more sensible (and is what my patch is
> working towards).
Doh (yes, "diff --git" was what I meant). As a mode-flipping patch
does not have hunk but does show the header, it wants to be included
in "git diff --stat" output, I would think, independent of -b issue.
In fact
chmod +x README.md
git diff --stat
does show a 0-line diffstat.
> Doing:
>
> >empty
> git add empty
> git diff --cached
>
> shows a "diff --git" header, but no hunk. I think it should show a
> diffstat (and does with my patch).
>
> I was thinking the rule should be something like:
>
> if (p->status == DIFF_STATUS_MODIFIED &&
> !file->added && !file->deleted))
>
> and otherwise include the entry, since it would be an add, delete,
> rename, etc, which carries useful information.
>
> Though a pure rename would not hit this code path at all, I would think
> (it would not trigger "!same_contents"). And a rename where there was a
> whitespace only change probably _should_ be omitted from "-b".
>
> Ditto for a pure mode change, I think. We do not run the contents
> through diff at all, so it does not hit this code path.
>
> -Peff
