view: do not offer links to 0-byte multipart attachments

Offering links to download 0-byte files is useless.  We could
waste memory by preserving $eml->{bdy} during iteration, but
offering attachments of type "multipart" is not very useful,
as users are usually interested in decoded attachments or
the entire raw message.

Fixes: e60231148eb604a3 ("descend into message/(rfc822|news|global) parts")

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 93a5b329..a05ac414 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -499,6 +499,11 @@ sub submsg_hdr ($$) {
 sub attach_link ($$$$;$) {
         my ($ctx, $ct, $p, $fn, $err) = @_;
         my ($part, $depth, $idx) = @$p;
+
+        # Eml iteration clobbers multipart ->{bdy}, so do not offer
+        # downloads for 0-byte multipart attachments
+        return unless $part->{bdy};
+
         my $nl = $idx eq '1' ? '' : "\n"; # like join("\n", ...)
         my $size = bytes::length($part->body);