qspawn: better annotate where $qx_cb is called

Hopefully this makes the code easier-to-follow for random
readers.  This requires a small amount of modification to
our one caller, but this is a new, unstable API (as is
nearly all of our code).

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/RepobrowseGitSnapshot.pm b/lib/PublicInbox/RepobrowseGitSnapshot.pm
index cceb4641..a9751b97 100644
--- a/lib/PublicInbox/RepobrowseGitSnapshot.pm
+++ b/lib/PublicInbox/RepobrowseGitSnapshot.pm
@@ -87,7 +87,7 @@ sub call_git_snapshot ($$) { # invoked by PublicInbox::RepobrowseBase::call
         $env->{'qspawn.quiet'} = 1;
         my $tree_cb = $env->{'repobrowse.tree_cb'} = sub {
                 my ($ref) = @_;
-                if (ref($ref) eq 'SCALAR') {
+                if (defined $ref) {
                         $tree = $$ref;
                         chomp $tree;
                 }