msg_iter: pass $idx as a scalar, not array

This doesn't make any difference for most multipart
messages (or any single part messages).  However,
this starts having space savings when parts start
nesting.

It also slightly simplifies callers.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/PublicInbox/WwwAttach.pm b/lib/PublicInbox/WwwAttach.pm
index 774b38ae..b1009907 100644
--- a/lib/PublicInbox/WwwAttach.pm
+++ b/lib/PublicInbox/WwwAttach.pm
@@ -11,9 +11,9 @@ use PublicInbox::MIME;
 use PublicInbox::MsgIter;
 
 sub get_attach_i { # ->each_part callback
-        my ($part, $depth, @idx) = @{$_[0]};
+        my ($part, $depth, $idx) = @{$_[0]};
         my $res = $_[1];
-        return if join('.', @idx) ne $res->[3]; # $idx
+        return if $idx ne $res->[3]; # [0-9]+(?:\.[0-9]+)+
         $res->[0] = 200;
         my $ct = $part->content_type;
         $ct = parse_content_type($ct) if $ct;