imap: quiet uninitialized variable warning on FETCH

This was triggered by blindly trying to FETCH an MSN (not
"UID FETCH") on an empty dummy inbox.  It's harmless, and
probably triggered by a wayward client or misbehaving bot.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/IMAP.pm b/lib/PublicInbox/IMAP.pm
index 2d0d005e..47c08aea 100644
--- a/lib/PublicInbox/IMAP.pm
+++ b/lib/PublicInbox/IMAP.pm
@@ -300,7 +300,7 @@ sub msn2uid ($) {
 # converts a set of message sequence numbers in requests to UIDs:
 sub msn_to_uid_range ($$) {
         my $msn2uid = $_[0];
-        $_[1] =~ s!([0-9]+)!$msn2uid->[$1 - 1] // ($msn2uid->[-1] + 1)!sge;
+        $_[1] =~ s!([0-9]+)!$msn2uid->[$1 - 1] // ($msn2uid->[-1] // 0 + 1)!sge;
 }
 
 # called by PublicInbox::InboxIdle