From: Junio C Hamano <gitster@pobox.com>
To: Taylor Blau <me@ttaylorr.com>
Cc: Thomas Guyot-Sionnest <tguyot@gmail.com>,
git@vger.kernel.org, dermoth@aei.ca, peff@peff.net
Subject: Re: [PATCH v2] diff: Fix modified lines stats with --stat and --numstat
Date: Sun, 20 Sep 2020 13:36:27 -0700 [thread overview]
Message-ID: <xmqqd02ggp84.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <xmqqlfh4gt5z.fsf@gitster.c.googlers.com> (Junio C. Hamano's message of "Sun, 20 Sep 2020 12:11:20 -0700")
Junio C Hamano <gitster@pobox.com> writes:
> Summarizing the above, I think the second best fix is this (which
> means that the posted patch is the third best):
>
> /*
> * diff_fill_oid_info() marked one/two->oid with null_oid
> * for a path whose oid is not available. Disable early
> * return optimization for them.
> */
> if (oideq(&one->oid, &null_oid) || oideq(&two->oid, &null_oid))
> same_contents = 0; /* could be different */
> else if (oideq(&one->oid, &two->oid))
> same_contents = 1; /* definitely the same */
> else
> same_contents = 0; /* definitely different */
A tangent.
There is this code in diff.c::fill_metainfo() that is used to
populate the "index" header element of "diff --patch" output:
if (one && two && !oideq(&one->oid, &two->oid)) {
const unsigned hexsz = the_hash_algo->hexsz;
int abbrev = o->abbrev ? o->abbrev : DEFAULT_ABBREV;
if (o->flags.full_index)
abbrev = hexsz;
if (o->flags.binary) {
mmfile_t mf;
if ((!fill_mmfile(o->repo, &mf, one) &&
diff_filespec_is_binary(o->repo, one)) ||
(!fill_mmfile(o->repo, &mf, two) &&
diff_filespec_is_binary(o->repo, two)))
abbrev = hexsz;
}
strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
diff_abbrev_oid(&one->oid, abbrev),
diff_abbrev_oid(&two->oid, abbrev));
if (one->mode == two->mode)
strbuf_addf(msg, " %06o", one->mode);
strbuf_addf(msg, "%s\n", reset);
}
Currently it is OK because there can only be one side that
diff_fill_oid_info() would mark as "oid unavailable" (e.g. reading
standard input stream). If a new feature is introducing a situation
where both ends have null_oid, which was so far been impossible,
we'd probably need to factor out the condition used in the above
into a helper function, e.g.
static int cannot_be_the_same(struct diff_filespec *one, struct diff_filespec *two)
{
if ((oideq(&one->oid, &null_oid) || oideq(&two->oid, &null_oid))
return 1;
else if (oideq(&one->oid, &two->oid))
return 0;
else
return 1;
}
and rewrite the conditional in fill_metainfo() to
if (one && two && cannot_be_the_same(one, two)) {
...
The "second best fix" could then become a single liner:
same_contents = !cannot_be_the_same(one, two);
using the helper.
next prev parent reply other threads:[~2020-09-20 20:36 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
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 [this message]
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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