Varun Naik <vcnaik94@xxxxxxxxx> writes:
> On Tue, Aug 13, 2019 at 1:33 PM Junio C Hamano <gitster@xxxxxxxxx> wrote:
>>
>> The original code considered that two entries with the same mode and
>> the same "contents" are the same. As nobody sane tracks an empty
>> file for an extended span of history, that meant that most of the
>> time, intent-to-add entries, which has the normal mode bits for the
>> blobs (with or without the executable bit) and object name for a
>> zero length blob, would have been judged "different".
>>
>
> I agree, this edge case is really arcane. The rabbit hole was deep :)
In retrospect, perhaps I shouldn't have used the empty-blob SHA-1
for I-T-A entries (instead, perhaps 0{40} or something impossible)
when I invented this feature at 39425819 ("git-add --intent-to-add
(-N)", 2008-08-21). It made the code to "diff" easier than having
to special case comparison between a real blob and an I-T-A entry,
but we are paying the price for that laziness with a discussion and
a patch like this one.
>> So perhaps
>>
>> + !ce_intent_to_add(a) && !ce_intent_to_add(b) &&
>>
>> i.e. "a cache entry is eligible to be same with something else only
>> when its I-T-A bit is unset".
>>
>
> I decided to follow René's suggestion in response to this. Patch coming soon.
Either is fine as the implementation of the same semantics; I
however am not sure if two I-T-A entries should compare "same" or
"not same", or if we are better off catching the caller that feeds
two I-T-A entries to same() with a BUG().
Thanks.
