mid: filter out 'y', 'n', and email addresses from references()

Looking at git@vger history, several emails had broken
References/In-Reply-To pointing to <y>, <n> and email
addresses as Message-IDs in References and In-Reply-To
headers.

This was causing too many unrelated messages to be linked
together in the same thread.

diff --git a/lib/PublicInbox/MID.pm b/lib/PublicInbox/MID.pm
index cd56f272613dc28551409593545eec5a2e80eb0e..7f1ab15ea731db8f0f70304662afe338754b5c6c 100644 (file)
--- a/lib/PublicInbox/MID.pm
+++ b/lib/PublicInbox/MID.pm
@@ -10,6 +10,7 @@ our @EXPORT_OK = qw/mid_clean id_compress mid2path mid_mime mid_escape MID_ESC
        mids references/;
 use URI::Escape qw(uri_escape_utf8);
 use Digest::SHA qw/sha1_hex/;
+require PublicInbox::Address;
 use constant {
        MID_MAX => 40, # SHA-1 hex length # TODO: get rid of this
        MAX_MID_SIZE => 244, # max term size (Xapian limitation) - length('Q')
@@ -79,22 +80,34 @@ sub references ($) {
                        push(@mids, ($v =~ /<([^>]+)>/sg));
                }
        }
-       uniq_mids(\@mids);
+
+       # old versions of git-send-email would prompt users for
+       # In-Reply-To and users' muscle memory would use 'y' or 'n'
+       # as responses:
+       my %addr = ( y => 1, n => 1 );
+
+       foreach my $f (qw(To From Cc)) {
+               my @v = $hdr->header_raw($f);
+               foreach my $v (@v) {
+                       $addr{$_} = 1 for (PublicInbox::Address::emails($v));
+               }
+       }
+       uniq_mids(\@mids, \%addr);
 }
 
-sub uniq_mids ($) {
-       my ($mids) = @_;
+sub uniq_mids ($;$) {
+       my ($mids, $seen) = @_;
        my @ret;
-       my %seen;
+       $seen ||= {};
        foreach my $mid (@$mids) {
                $mid =~ tr/\n\t\r//d;
                if (length($mid) > MAX_MID_SIZE) {
                        warn "Message-ID: <$mid> too long, truncating\n";
                        $mid = substr($mid, 0, MAX_MID_SIZE);
                }
-               next if $seen{$mid};
+               next if $seen->{$mid};
                push @ret, $mid;
-               $seen{$mid} = 1;
+               $seen->{$mid} = 1;
        }
        \@ret;
 }

diff --git a/t/mid.t b/t/mid.t
index 8c307c825d22a7e2747c8f35fb1df0909c798dcb..69a8a708ec0b623a2db296ff9b0e56a2bba26233 100644 (file)
--- a/t/mid.t
+++ b/t/mid.t
@@ -36,6 +36,10 @@ is(mid_escape('foo%!@(bar)'), 'foo%25!@(bar)');
        $mime->header_set('Message-ID', "<hello\tworld>");
        is_deeply(mids($mime->header_obj), ['helloworld'],
                'drop \t in Message-ID');
+
+       $mime->header_set('To', 'u@example.com');
+       $mime->header_set('References', '<hello> <world> <n> <u@example.com>');
+       is_deeply(references($mime->header_obj), [qw(hello world)]);
 }
 
 done_testing();