view: avoid uninitialized var from diff query textarea

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should not litter stderr or syslog with uninitialized variable
warnings.

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 275258e3f29ed6ce3a78a0625910cff834376f02..7ca85a859b51fdb1e8df1a623ac02f4d764c40ba 100644 (file)
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -849,7 +849,7 @@ sub thread_skel ($$$) {
 sub dfqry_text ($$) {
        my ($ctx, $subj) = @_;
        my $qry_dfblob = delete $ctx->{-qry_dfblob} or return (undef);
-       my @bs = split /["\x{201c}\x{201d}]+/, $subj;
+       my @bs = split /["\x{201c}\x{201d}]+/, $subj // '';
        my $q = join ' ', (@bs ? ('(') : ()), map {
                chop if length > 7; # include 1 abbrev "older" patches
                "dfblob:$_";