[PATCH 2/2] lei_mirror: break circular references

[Eric Wong <e@80x24.org>]

It seems more graceful than dying and breaking a mirror, since
the {reference} in util-linux was irrelevant anyways with the
move to forkgroups.
---
 lib/PublicInbox/LeiMirror.pm | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/LeiMirror.pm b/lib/PublicInbox/LeiMirror.pm
index d6d2c69e..92156cf1 100644
--- a/lib/PublicInbox/LeiMirror.pm
+++ b/lib/PublicInbox/LeiMirror.pm
@@ -960,9 +960,13 @@ sub clone_all {
 			# resolve multi-level references
 			while ($m && defined($nxt = $m->{$x}->{reference})) {
 				exists($todo->{$nxt}) or last;
-				die <<EOM if ++$nr > 1000;
-E: dependency loop detected (`$x' => `$nxt')
+				if (++$nr > 1000) {
+					$m->{$x}->{reference} = undef;
+					$m->{$nxt}->{reference} = undef;
+					warn <<EOM
+E: dependency loop detected (`$x' => `$nxt'), breaking
 EOM
+				}
 				$x = $nxt;
 			}
 			my $y = delete $todo->{$x} // next; # already done