search: stop assuming Message-ID is unique

In general, they are, but there's no way for or general purpose
mail server to enforce that.  This is a step in allowing us
to handle more corner cases which existing lists throw at us.

1 files changed, 12 insertions, 2 deletions

diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index 3ec96ca9..33a1f2d3 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -56,7 +56,7 @@ my %bool_pfx_internal = (
 );
 
 my %bool_pfx_external = (
-        mid => 'XMID', # uniQue id (Message-ID)
+        mid => 'XMID', # Message-ID (full/exact)
 );
 
 my %prob_prefix = (
@@ -285,7 +285,7 @@ sub lookup_message {
         my ($self, $mid) = @_;
         $mid = mid_clean($mid);
 
-        my $doc_id = $self->find_unique_doc_id('XMID' . $mid);
+        my $doc_id = $self->find_first_doc_id('XMID' . $mid);
         my $smsg;
         if (defined $doc_id) {
                 # raises on error:
@@ -327,6 +327,16 @@ sub find_doc_ids {
         ($db->postlist_begin($termval), $db->postlist_end($termval));
 }
 
+sub find_first_doc_id {
+        my ($self, $termval) = @_;
+
+        my ($begin, $end) = $self->find_doc_ids($termval);
+
+        return undef if $begin->equal($end); # not found
+
+        $begin->get_docid;
+}
+
 # normalize subjects so they are suitable as pathnames for URLs
 # XXX: consider for removal
 sub subject_path {