searchidx: fix obvious typo

We can't pass an empty string to `git merge-base --is-ancestor'
AFAIK, this did NOT present issues in the current test suite.

diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 9c291066487d03be512706442f45df4c3e1022c4..b963805ee237314d0aefc2a346b89bbebc683039 100644 (file)
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -694,7 +694,7 @@ sub _last_x_commit {
                $lx = $lm;
        }
        # Use last_commit from msgmap if it is older or unset
-       if (!$lm || ($lx && $lx && is_ancestor($self->{git}, $lm, $lx))) {
+       if (!$lm || ($lx && $lm && is_ancestor($self->{git}, $lm, $lx))) {
                $lx = $lm;
        }
        $lx;