view: handle the topic-free case properly

There may be no topics for a given timestamp range,
so don't attempt to treat `undef' as an arrayref.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 89174296..c42654b6 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -1056,7 +1056,7 @@ sub acc_topic { # walk_thread callback
 sub dump_topics {
         my ($ctx) = @_;
         my $order = delete $ctx->{order}; # [ ds, subj1, subj2, subj3, ... ]
-        if (!@$order) {
+        unless ($order) {
                 $ctx->{-html_tip} = '<pre>[No topics in range]</pre>';
                 return 404;
         }