disallow "\t" and "\n" in OVER headers

For Subject/To/Cc/From headers, we squeeze them to a space (' ').

For Message-IDs (including References/In-Reply-To), '\t', '\n', '\r'
are deleted since some MUAs might screw them up:

  https://public-inbox.org/git/656C30A1EFC89F6B2082D9B6@localhost/raw

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/SearchMsg.pm b/lib/PublicInbox/SearchMsg.pm
index ab971e00..c7787ea1 100644
--- a/lib/PublicInbox/SearchMsg.pm
+++ b/lib/PublicInbox/SearchMsg.pm
@@ -100,7 +100,7 @@ sub __hdr ($$) {
         my $mime = $self->{mime} or return;
         $val = $mime->header($field);
         $val = '' unless defined $val;
-        $val =~ tr/\n/ /;
+        $val =~ tr/\t\n/  /;
         $val =~ tr/\r//d;
         $self->{$field} = $val;
 }