v2writable: warn on duplicate Message-IDs

This should give us an idea of how much a problem deduplication
will be.

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index cc7e7ec9..f9207e94 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -515,13 +515,15 @@ sub unindex_blob {
 }
 
 sub index_mm {
-        my ($self, $mime) = @_;
+        my ($self, $mime, $warn_existing) = @_;
         my $mid = mid_clean(mid_mime($mime));
         my $mm = $self->{mm};
         my $num = $mm->mid_insert($mid);
+        return $num if defined $num;
 
+        warn "<$mid> reused\n" if $warn_existing;
         # fallback to num_for since filters like RubyLang set the number
-        defined $num ? $num : $mm->num_for($mid);
+        $mm->num_for($mid);
 }
 
 sub unindex_mm {