Hi,
On Thu, 15 Jan 2009, Thomas Rast wrote:
> Thomas Rast wrote:
> > Johannes Schindelin wrote:
> > > If a hunk header '@@ -2 +1,0 @@' is found that logically should be
> > > '@@ -2 +2,0 @@', diff_words got confused.
> > [...]
> > > This might be a libxdiff issue, though.
> >
> > Looks like it's just bug-for-bug compatible with diff. At least my
> > GNU diffutils 2.8.7 show the same behaviour.
>
> I think the culprit is in
>
> commit ca557afff9f7dad7a8739cd193ac0730d872e282
> Author: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
> Date: Mon Apr 3 18:47:55 2006 -0700
>
> Clean-up trivially redundant diff.
>
> Also corrects the line numbers in unified output when using
> zero lines context.
> [...]
> diff --git a/xdiff/xutils.c b/xdiff/xutils.c
> [...]
> @@ -244,7 +257,7 @@ int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
> memcpy(buf, "@@ -", 4);
> nb += 4;
>
> - nb += xdl_num_out(buf + nb, c1 ? s1: 0);
> + nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
Junio mentioned some POSIX document in which this behavior is actually
required. So I'll fix my code thusly:
-- snipsnap --
diff --git a/diff.c b/diff.c
index 3709651..219a242 100644
--- a/diff.c
+++ b/diff.c
@@ -353,30 +353,20 @@ static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
&minus_first, &minus_len, &plus_first, &plus_len))
return;
- minus_begin = diff_words->minus.orig[minus_first].begin;
- minus_end = minus_len == 0 ? minus_begin :
- diff_words->minus.orig[minus_first + minus_len - 1].end;
- plus_begin = diff_words->plus.orig[plus_first].begin;
- plus_end = plus_len == 0 ? plus_begin :
- diff_words->plus.orig[plus_first + plus_len - 1].end;
+ /* POSIX requires that first be decremented by one if len == 0... */
+ if (minus_len) {
+ minus_begin = diff_words->minus.orig[minus_first].begin;
+ minus_end =
+ diff_words->minus.orig[minus_first + minus_len - 1].end;
+ } else
+ minus_begin = minus_end =
+ diff_words->minus.orig[minus_first].end;
- /*
- * since this is a --unified=0 diff, it can result in a single hunk
- * with a header like this: @@ -2 +1,0 @@
- *
- * This breaks the assumption that minus_first == plus_first.
- *
- * So we have to fix it: whenever we reach the end of pre and post
- * texts, but nothing was added, we need to shift the plus part
- * to the end of the buffer.
- *
- * It is only necessary for the plus part, as we show the common
- * words from that buffer.
- */
- if (plus_len == 0 && minus_first + minus_len
- == diff_words->minus.orig_nr)
- plus_begin = plus_end =
- diff_words->plus.orig[diff_words->plus.orig_nr - 1].end;
+ if (plus_len) {
+ plus_begin = diff_words->plus.orig[plus_first].begin;
+ plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
+ } else
+ plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
if (diff_words->current_plus != plus_begin)
fwrite(diff_words->current_plus,
--
1.6.1.300.gbc493
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