Re: [PATCH 1/2] diff: Fix modified lines stats with --stat and --numstat

From: Thomas Guyot <tguyot@gmail.com>
Date: Sep 24, 2020, 04:49 UTC
Message-ID: <1d0a60c3-d15e-bcbb-f042-2f8ae06f0de1@gmail.com>
In-Reply-To: <nycvar.QRO.7.76.6.2009232244000.5061@tvgsbejvaqbjf.bet>

Hi,

On 2020-09-23 16:44, Johannes Schindelin wrote:

Show 15 quoted lines

> Hi Junio,
> 
> On Wed, 23 Sep 2020, Junio C Hamano wrote:
> 
>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>
>>> I believe that that is exactly the reason why we want this:
>>>
>>> -	same_contents = oideq(&one->oid, &two->oid);
>>> +	same_contents = one->oid_valid && two->oid_valid ?
>>> 		oideq(&one->oid, &two->oid) : !strcmp(one->data, two->data);
>>
>> Not quite.  The other side should either be
>>
>> 	one->size == two->size && !memcmp(...)

Thanks for all the feedback, that was enlightening. Although I have been silent the past few days I watched this thread with interest.

So as Junio pointed out this is merely an optimization - the range-diff test that I corrected also showed two 0-line diffs and I realized there's a block further down that should explicitly removes them, under

    else if (!same_contents) {

We can even remove same_contents entirely and everything work just fine after adjusting the range-diff test - the logic is correct and underlying functions already DTRT.

My next patch simplifies the test down to:

    same_contents = one->oid_valid && two->oid_valid &&
        oideq(&one->oid, &two->oid);

My understanding is that oid_valid will never be true for a modified (even mode change) or out of tree file so it's a valid assumption.

I'll also rename that variable to "same_oid" - the current name is misleading both ways (true doesn't means there will be diffs, false doesn't mean contents differs).

Regards,

Thomas