filter: preserve QP when collapsing multipart

HTML clients also tend to send quoted-printable crap in
their plain-text parts, preserve that so it's displayed
correctly for all QP-capable handlers.

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/PublicInbox/Filter.pm b/lib/PublicInbox/Filter.pm
index a1587682..e784cded 100644
--- a/lib/PublicInbox/Filter.pm
+++ b/lib/PublicInbox/Filter.pm
@@ -201,6 +201,10 @@ sub collapse {
         my ($mime, $part) = @_;
         $mime->header_set('Content-Type', $part->content_type);
         $mime->body_set($part->body_raw);
+        my $cte = $part->header('Content-Transfer-Encoding');
+        if (defined($cte) && length($cte)) {
+                $mime->header_set('Content-Transfer-Encoding', $cte);
+        }
         mark_changed($mime);
         return 1;
 }