log -m output

> I have a question about log command.
> Probably I'm just missing something but anyway.
> I can illustrate the question on the repository of Git.
> Let's look at revision 1ed91937
> It is a merge based on pair of revisions a9572072 and 294c695d.
> According to blame these parent revisions have different content for
> delta.h file.

> On Mon, Oct 07, 2019 at 07:14:25PM +0400, Semyon Kirnosenko wrote:
>> I have a question about log command.
>> Probably I'm just missing something but anyway.
>> I can illustrate the question on the repository of Git.
>> Let's look at revision 1ed91937
>> It is a merge based on pair of revisions a9572072 and 294c695d.
>> According to blame these parent revisions have different content for
>> delta.h file.
> 
> I'm not sure what you mean by this statement; what blame command did
> you run?
> 
>> But when I get log with -m flag for merge revision, I can't see that
>> file in the list of changed files.
>> Why?
> 
> The contents of 'delta.h' is identical in both parents of that merge:
> 
>    $ git diff a9572072 294c695d delta.h
>    $
>    # no difference
> 
> So 'git log -m' does the right thing by not showing 'delta.h'.
> 
> .
> 

>
> On 2019-10-07 20:43, SZEDER Gábor wrote:
> > On Mon, Oct 07, 2019 at 07:14:25PM +0400, Semyon Kirnosenko wrote:
> >> I have a question about log command.
> >> Probably I'm just missing something but anyway.
> >> I can illustrate the question on the repository of Git.
> >> Let's look at revision 1ed91937
> >> It is a merge based on pair of revisions a9572072 and 294c695d.
> >> According to blame these parent revisions have different content for
> >> delta.h file.
> >
> > I'm not sure what you mean by this statement; what blame command did
> > you run?
> >
> >> But when I get log with -m flag for merge revision, I can't see that
> >> file in the list of changed files.
> >> Why?
> >
> > The contents of 'delta.h' is identical in both parents of that merge:
> >
> >    $ git diff a9572072 294c695d delta.h
> >    $
> >    # no difference
> >
> > So 'git log -m' does the right thing by not showing 'delta.h'.
> >
> > .
> >
>
> But blame shows different results:
>
> git blame a9572072 delta.h
> git blame 294c695d delta.h

> On Mon, Oct 7, 2019 at 10:05 AM Semyon Kirnosenko <kirnosenko@mail.ru> wrote:
>>
>> On 2019-10-07 20:43, SZEDER Gábor wrote:
>>> On Mon, Oct 07, 2019 at 07:14:25PM +0400, Semyon Kirnosenko wrote:
>>>> I have a question about log command.
>>>> Probably I'm just missing something but anyway.
>>>> I can illustrate the question on the repository of Git.
>>>> Let's look at revision 1ed91937
>>>> It is a merge based on pair of revisions a9572072 and 294c695d.
>>>> According to blame these parent revisions have different content for
>>>> delta.h file.
>>>
>>> I'm not sure what you mean by this statement; what blame command did
>>> you run?
>>>
>>>> But when I get log with -m flag for merge revision, I can't see that
>>>> file in the list of changed files.
>>>> Why?
>>>
>>> The contents of 'delta.h' is identical in both parents of that merge:
>>>
>>>     $ git diff a9572072 294c695d delta.h
>>>     $
>>>     # no difference
>>>
>>> So 'git log -m' does the right thing by not showing 'delta.h'.
>>>
>>> .
>>>
>>
>> But blame shows different results:
>>
>> git blame a9572072 delta.h
>> git blame 294c695d delta.h
> 
> blame does not at all claim those two revisions have different
> versions of delta.h:
> 
> $ diff -u <(git blame a9572072 delta.h) <(git blame 294c695d delta.h)
> --- /dev/fd/63    2019-10-07 10:16:43.092356078 -0700
> +++ /dev/fd/62    2019-10-07 10:16:43.092356078 -0700
> @@ -9,8 +9,8 @@
>   a310d434946 (Nicolas Pitre  2005-05-19 10:27:14 -0400  9)
>   void *delta_buf, unsigned long delta_size,
>   a310d434946 (Nicolas Pitre  2005-05-19 10:27:14 -0400 10)
>   unsigned long *dst_size);
>   d1af002dc60 (Nicolas Pitre  2005-05-20 16:59:17 -0400 11)
> -dcde55bc58a (Nicolas Pitre  2005-06-29 02:49:56 -0400 12) /* the
> smallest possible delta size is 4 bytes */
> -dcde55bc58a (Nicolas Pitre  2005-06-29 02:49:56 -0400 13) #define
> DELTA_SIZE_MIN    4
> +c7a45bd20e4 (Junio C Hamano 2005-12-12 16:42:38 -0800 12) /* the
> smallest possible delta size is 4 bytes */
> +c7a45bd20e4 (Junio C Hamano 2005-12-12 16:42:38 -0800 13) #define
> DELTA_SIZE_MIN    4
>   dcde55bc58a (Nicolas Pitre  2005-06-29 02:49:56 -0400 14)
>   dcde55bc58a (Nicolas Pitre  2005-06-29 02:49:56 -0400 15) /*
>   dcde55bc58a (Nicolas Pitre  2005-06-29 02:49:56 -0400 16)  * This
> must be called twice on the delta data buffer, first to get t
> 
> It does say that _how_ those two arrived at the *same* version of the
> file differed, but if you compare the portions of the differing lines
> corresponding to the actual file contents you see that they are the
> same...just as SZEDER pointed out.
>