lei_search: avoid unconditional warning when no exception

Oops, we shouldn't warn on "$@" unless "$@" is truthy.

Fixes: c7bcfe6cd6648ff0 ("lei: diagnostics for /Document \d+ not found/ errors")

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/PublicInbox/LeiSearch.pm b/lib/PublicInbox/LeiSearch.pm
index f9e5c8e9..47160ed9 100644
--- a/lib/PublicInbox/LeiSearch.pm
+++ b/lib/PublicInbox/LeiSearch.pm
@@ -64,7 +64,8 @@ sub _xsmsg_vmd { # retry_reopen
                                 %L = (%L, %$x);
                         }
                 };
-                warn "$$ $0 #$num (nshard=$self->{nshard}) $smsg->{blob}: $@";
+                warn "$$ $0 #$num (nshard=$self->{nshard}) $smsg->{blob}: $@"
+                        if $@;
         }
         $smsg->{kw} = [ sort keys %kw ] if scalar(keys(%kw));
         $smsg->{L} = [ sort keys %L ] if scalar(keys(%L));