From d6b7a19e8490d799007f805caea92ab0f9f934c9 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Wed, 2 Oct 2024 22:39:02 +0000
Subject: [PATCH] viewvcs: generate search query for merge commits

Attempt to parse commit titles out of merge commit messages and
generate search queries out of them to find the related emails
for the individual patch(es).

As with all search-related functionality, it's best-effort
and inexact, but seems somewhat successful.
---
 lib/PublicInbox/ViewVCS.pm | 70 ++++++++++++++++++++++++++++----------
 1 file changed, 52 insertions(+), 18 deletions(-)

diff --git a/lib/PublicInbox/ViewVCS.pm b/lib/PublicInbox/ViewVCS.pm
index 49477619d..d9df671c2 100644
--- a/lib/PublicInbox/ViewVCS.pm
+++ b/lib/PublicInbox/ViewVCS.pm
@@ -154,7 +154,7 @@ sub do_check_async {
 	}
 }
 
-sub cmt_hdr_prep { # psgi_qx cb
+sub cmt_hdr_prep { # psgi_qx cb for "git show" commit output
 	my ($fh, $ctx, $cmt_fin) = @_;
 	return if $ctx->{-qsp_err_h}; # let cmt_fin handle it
 	seek $fh, 0, SEEK_SET;
@@ -221,7 +221,26 @@ sub ibx_url_for {
 	wantarray ? (@ret) : $ret[0];
 }
 
-sub cmt_fin { # OnDestroy cb
+sub prep_merge_titles ($) {
+	my ($in_titles, @s, $t, @lines);
+	chomp(@lines = split /^/ms, $_[0]);
+	for (@lines) {
+		if (/^\* /) { # * branch/name:
+			$in_titles = 1;
+		} elsif ($in_titles) { # commit titles
+			if (s/^  //) { # break up Xapian phrases
+				$t = join " AND\n ", map { qq{s:"$_"} }
+					split /["\x{201c}\x{201d}]+/;
+				push @s, $t if $t ne 's:"..."';
+			} else { # trailing text or trailers?
+				undef $in_titles;
+			}
+		} # else: preamble text
+	}
+	@s ? \@s : undef;
+}
+
+sub cmt_fin { # OnDestroy cb for `git show' commit output
 	my ($ctx) = @_;
 	my ($eh, $ep) = delete @$ctx{qw(-qsp_err_h -qsp_err_p)};
 	if ($eh || $ep) {
@@ -242,7 +261,17 @@ sub cmt_fin { # OnDestroy cb
 		$au =~ s/>/>$x/;
 	}
 	$_ = ascii_html($_) for ($au, $co);
-	my $ibx_url = ibx_url_for($ctx) // $upfx;
+	my ($merge_titles, $ibx_url, $ibx_url_html, $alt);
+	$ibx_url = ibx_url_for($ctx);
+	if (defined $ibx_url) {
+		$ibx_url =~ m!://! or
+			substr($ibx_url, 0, 0, '../../../');
+		$ibx_url_html = ascii_html($ibx_url);
+		$alt = " `$ibx_url_html'";
+	} else {
+		$ibx_url = $ibx_url_html = $upfx;
+		$alt = '';
+	}
 	$au =~ s!(&gt; +)([0-9]{4,}-\S+ \S+)!
 		my ($gt, $t) = ($1, $2);
 		$t =~ tr/ :-//d;
@@ -258,6 +287,7 @@ title="list contemporary emails">$2</a>)
 		$x = qq{ (<a
 href="$f.patch">patch</a>)\n   <a href=#parent>parent</a> $P->[0]};
 	} elsif (@$P > 1) {
+		$merge_titles = 1;
 		$x = qq(\n  <a href=#parents>parents</a> $P->[0]\n);
 		shift @$P;
 		$x .= qq(          $_\n) for @$P;
@@ -275,7 +305,10 @@ committer $co
 
 <b>$title_html</b>
 EOM
-	print $zfh "\n", $ctx->{-linkify}->to_html($bdy) if length($bdy);
+	if (length($bdy)) {
+		print $zfh "\n", $ctx->{-linkify}->to_html($bdy);
+		$merge_titles = prep_merge_titles $bdy if $merge_titles;
+	}
 	undef $bdy; # free memory
 	my $fh = delete $ctx->{patch_fh};
 	if (-s $fh > $MAX_SIZE) {
@@ -293,26 +326,27 @@ EOM
 		# commit?
 		print $zfh '</pre>';
 		my ($rows, $q) = PublicInbox::View::dfqry_text $ctx, $s;
-		if ($rows) {
-			my $ibx_url = ibx_url_for($ctx);
-			my $alt;
-			if (defined $ibx_url) {
-				$alt = " `$ibx_url'";
-				$ibx_url =~ m!://! or
-					substr($ibx_url, 0, 0, '../../../');
-				$ibx_url = ascii_html($ibx_url);
-			} else {
-				$ibx_url = $upfx;
-				$alt = '';
-			}
-			print $zfh <<EOM;
+		print $zfh <<EOM if $rows;
 <hr><form action="$ibx_url"
 id=related><pre>find related emails, including ancestors/descendants/conflicts
 <textarea name=q cols=78 rows=$rows>$q</textarea>
 <input type=submit value="search$alt"
 />\t(<a href="${ibx_url}_/text/help/">help</a>)</pre></form>
 EOM
-		}
+	}
+	if (ref $merge_titles) {
+		print $zfh <<EOM;
+<hr><form action="$ibx_url" id=merged><pre>find merged patch emails
+<textarea name=q cols=78
+EOM
+		my $nr = scalar @$merge_titles;
+		$merge_titles = ascii_html(join ") OR\n(", @$merge_titles);
+		print $zfh 'rows=', $nr, '>(', $merge_titles, <<EOM;
+)</textarea>
+<input type=submit value="search$alt"
+/></pre></form>
+EOM
+		undef $merge_titles;
 	}
 	chop($x = <<EOM);
 <hr><pre>glossary
-- 
2.47.2