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From: Thomas Guyot <tguyot@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	Jeff King <peff@peff.net>,
	git@vger.kernel.org, Thomas Guyot-Sionnest <dermoth@aei.ca>
Subject: Re: [PATCH 1/2] diff: Fix modified lines stats with --stat and --numstat
Date: Thu, 24 Sep 2020 03:13:53 -0400	[thread overview]
Message-ID: <34484667-1085-c60b-9438-591faed41ddc@gmail.com> (raw)
In-Reply-To: <xmqq4knnisn9.fsf@gitster.c.googlers.com>

Hi Junio,

On 2020-09-24 02:40, Junio C Hamano wrote:
> Thomas Guyot <tguyot@gmail.com> writes:
> 
> It is not "both ways", I think.  The idea is that when this variable
> is true, we know with certainty that these two are the same, but
> even when the variable is false, they still can be the same.  So
> true does mean there will not be diff.  False indeed is fuzzy.

I meant to say the old behavior "lied" in both directions.

> And as long as one side gives a 100% correct answer cheaply, we can
> use it as an optimization (and 'true' being that side in this case).
> 
> I have a mild suspicion that the name same_anything conveys a wrong
> impression, no matter what word you use for <anything>.  It does not
> capture that we are saying the "true" side has no false positive.
> 
> And that is why I alluded to "may_differ" earlier (with opposite
> polarity).  The flow would become:
> 
>     may_differ = !one->oid_valid || !two->oid_valid || !oideq(...);
> 
>     if (binary) {
>         if (!may_differ) {
>             added = deleted = 0;
>             ...
>         } else {
>             ... count added and deleted ...
>         }
>     } else if (rewrite) {
> 	...
>     } else if (may_differ) {
> 	... use xdl ...
>     }
> 
> and it would become quite straight-forward to follow.  When there is
> no chance that they may be different, we short-cut and otherwise we
> compute without cheating.  Only when they can be different, we do
> the expensive xdl thing.

I toyed a bit on the binary side... I never sent my 2nd reply as I still
needed to dig up; testing with diff_filespec_is_binary() { return 1; } I
would get (as expected) the same false-positive modified binary files I
used to get in range-diff test.

What I didn't get is applying the same logic
(free_diffstat_file(file);diffstat->nr--;) didn't have any effect. I'll
have to find what differs here to make binary files how up regardless.

Regards,

Thomas

  reply	other threads:[~2020-09-24  7:14 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-18 11:32 Allow passing pipes to diff --no-index + bugfix Thomas Guyot-Sionnest
2020-09-18 11:32 ` [PATCH 1/2] diff: Fix modified lines stats with --stat and --numstat Thomas Guyot-Sionnest
2020-09-18 14:46   ` Taylor Blau
2020-09-18 15:10     ` Thomas Guyot-Sionnest
2020-09-18 17:37       ` Jeff King
2020-09-18 18:00         ` Thomas Guyot-Sionnest
2020-09-20  4:53       ` Thomas Guyot
2020-09-18 17:27   ` Jeff King
2020-09-18 17:52     ` Thomas Guyot-Sionnest
2020-09-18 18:06       ` Junio C Hamano
2020-09-23 19:16         ` Johannes Schindelin
2020-09-23 19:23           ` Junio C Hamano
2020-09-23 20:44             ` Johannes Schindelin
2020-09-24  4:49               ` Thomas Guyot
2020-09-24  5:24                 ` [PATCH v3] " Thomas Guyot-Sionnest
2020-09-24  7:41                   ` [PATCH v4] " Thomas Guyot-Sionnest
2020-09-24  6:40                 ` [PATCH 1/2] " Junio C Hamano
2020-09-24  7:13                   ` Thomas Guyot [this message]
2020-09-24 17:19                     ` Junio C Hamano
2020-09-24 17:38                       ` Junio C Hamano
2020-09-23 15:05     ` Johannes Schindelin
2020-09-20 13:09   ` [PATCH v2] " Thomas Guyot-Sionnest
2020-09-20 15:39     ` Taylor Blau
2020-09-20 16:38       ` Thomas Guyot
2020-09-20 19:11       ` Junio C Hamano
2020-09-20 20:08         ` Junio C Hamano
2020-09-20 20:36         ` Junio C Hamano
2020-09-20 22:15           ` Junio C Hamano
2020-09-21 19:26         ` Jeff King
2020-09-21 21:51           ` Junio C Hamano
2020-09-21 22:20             ` Jeff King
2020-09-21 22:37               ` Junio C Hamano
2020-09-18 11:32 ` [PATCH 2/2] Allow passing pipes for input pipes to diff --no-index Thomas Guyot-Sionnest
2020-09-18 14:36   ` Taylor Blau
2020-09-18 16:34     ` Thomas Guyot-Sionnest
2020-09-18 17:19       ` Jeff King
2020-09-18 17:21         ` Jeff King
2020-09-18 17:39         ` Thomas Guyot-Sionnest
2020-09-18 17:48         ` Junio C Hamano
2020-09-18 18:02           ` Jeff King
2020-09-20 12:54             ` Thomas Guyot
2020-09-21 19:31               ` Jeff King
2020-09-21 20:14                 ` Junio C Hamano
2020-09-18 17:58       ` Taylor Blau
2020-09-18 18:05         ` Jeff King
2020-09-18 17:20     ` Jeff King
2020-09-18 18:00       ` Taylor Blau
2020-09-18 21:56   ` brian m. carlson
2020-09-18 17:51 ` Allow passing pipes to diff --no-index + bugfix Junio C Hamano
2020-09-18 18:24   ` Thomas Guyot-Sionnest

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