www_listing: fix odd "locate inbox" cases

Searching inboxes with an empty query no longer gives 500 errors
due to Xapian.  Also, improve the error message when no inboxes
match, since saying no inboxes exist yet is wrong.

1 files changed, 6 insertions, 1 deletions

diff --git a/lib/PublicInbox/WwwListing.pm b/lib/PublicInbox/WwwListing.pm
index eabda98a..1bb5fbd0 100644
--- a/lib/PublicInbox/WwwListing.pm
+++ b/lib/PublicInbox/WwwListing.pm
@@ -96,7 +96,8 @@ sub add_misc_ibx { # MiscSearch->retry_reopen callback
 
         delete $ctx->{-list}; # reset if retried
         my $pi_cfg = $ctx->{www}->{pi_cfg};
-        if (defined(my $user_query = $q->{'q'})) {
+        my $user_query = $q->{'q'} // '';
+        if ($user_query =~ /\S/) {
                 $qs = "( $qs ) AND ( $user_query )";
         } else { # special case for ALL
                 $ctx->ibx_entry($pi_cfg->ALL // die('BUG: ->ALL expected'), {});
@@ -218,6 +219,10 @@ sub psgi_triple {
                 $gzf->zmore('<pre>');
                 $gzf->zmore(join("\n", @$list));
                 $gzf->zmore(mset_footer($ctx, $mset)) if $mset;
+        } elsif (my $mset = delete $ctx->{-mset}) {
+                $gzf->zmore(mset_nav_top($ctx, $mset));
+                $gzf->zmore('<pre>no matching inboxes');
+                $gzf->zmore(mset_footer($ctx, $mset));
         } else {
                 $gzf->zmore('<pre>no inboxes, yet');
         }