From: Eric Wong <e@80x24.org>
Date: Mon, 6 Feb 2017 19:54:25 +0000 (+0000)
Subject: searchidx: deal with empty In-Reply-To and References headers
X-Git-Tag: v1.0.0~87
X-Git-Url: http://www.git.stargrave.org/?p=public-inbox.git;a=commitdiff_plain;h=83425ef12e4b65cdcecd11ddcb38175d4a91d5a0;hp=c41c7aa95d55dcff7cb01a744bbf1bfb200e23b4

searchidx: deal with empty In-Reply-To and References headers

In some messages, these headers exist, but have empty values.
Do not let empty values throw off our search indexer to tie
threads together, as it can make non-sensical threads grouped
to a Message-Id of "" (empty string).

See
<https://public-inbox.org/git/11340844841342-git-send-email-mailing-lists.git@rawuncut.elitemail.org/raw>
for an example of such a message.

Thanks-to: Johannes Schindelin <Johannes.Schindelin@gmx.de>
  <https://public-inbox.org/git/alpine.DEB.2.20.1702041206130.3496@virtualbox/>
---

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index d63dd7c7..1142ca7a 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -292,11 +292,15 @@ sub link_message {
 	my $mime = $smsg->{mime};
 	my $hdr = $mime->header_obj;
 	my $refs = $hdr->header_raw('References');
-	my @refs = $refs ? ($refs =~ /<([^>]+)>/g) : ();
+	my @refs = defined $refs ? ($refs =~ /<([^>]+)>/g) : ();
 	my $irt = $hdr->header_raw('In-Reply-To');
 	if (defined $irt) {
-		$irt = mid_clean($irt);
-		$irt = undef if $mid eq $irt;
+		if ($irt eq '') {
+			$irt = undef;
+		} else {
+			$irt = mid_clean($irt);
+			$irt = undef if $mid eq $irt;
+		}
 	}
 
 	my $tid;