[PATCH] viewdiff: do not anchor using diffstat comments

[Eric Wong <e@80x24.org>]

SZEDER Gábor <szeder.dev@gmail.com> wrote:
> Hi,
> 
> being able to jump around from diffstat to the diff of a particular
> file and back by simply clicking on links is great, but it doesn't
> seem to work with newly added files.  Consider this message:

Glad you noticed this feature :)  I keep forgetting to do more
work on it (fixing interdiffs and such), and also writing
automated tests to catch it.

>   https://public-inbox.org/git/20190624130226.17293-2-pclouds@gmail.com/
> 
> Clicking on the link that is the name of the doc source file or any of
> the C source of header files in the diffstat jumps to the diff of the
> particular file, but clicking on the link of any of the two new test
> files doesn't go anywhere.  Conversely, in the "diff --git a/...
> b/..." lines of the doc and source files the word "diff" is a link
> pointing back to the diffstat, but in the diff lines of those two new
> test files there is no link.

Thanks for the bug report.  The following should fix it,
it's also deployed on public-inbox.org

---------8<--------
Subject: [PATCH] viewdiff: do not anchor using diffstat comments

Diffstat summary comments were added to git last year and
we need to filter them out to get anchors working properly.

Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
  https://public-inbox.org/meta/20190704231123.GF20404@szeder.dev/
---
 lib/PublicInbox/ViewDiff.pm | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index b7dab81..4669e87 100644
--- a/lib/PublicInbox/ViewDiff.pm
+++ b/lib/PublicInbox/ViewDiff.pm
@@ -41,6 +41,9 @@ my $OID_BLOB = '[a-f0-9]{7,40}';
 my $PATH_A = '"?a/.+|/dev/null';
 my $PATH_B = '"?b/.+|/dev/null';
 
+# cf. git diff.c :: get_compact_summary
+my $DIFFSTAT_COMMENT = qr/\((?:new|gone|(?:(?:new|mode) [\+\-][lx]))\)/;
+
 sub to_html ($$) {
 	$_[0]->linkify_1($_[1]);
 	$_[0]->linkify_2(ascii_html($_[1]));
@@ -89,7 +92,7 @@ sub anchor0 ($$$$$) {
 	# So only do best-effort handling of renames for common cases;
 	# which works well in practice. If projects put "=>", or trailing
 	# spaces in filenames, oh well :P
-	$fn =~ s/ +\z//s;
+	$fn =~ s/(?: *$DIFFSTAT_COMMENT)? *\z//so;
 	$fn =~ s/{(?:.+) => (.+)}/$1/ or $fn =~ s/.* => (.+)/$1/;
 	$fn = git_unquote($fn);
 
-- 
EW