From 0ef7fb8a3edb8880ccb50d4d430ef92f7a8093f5 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Mon, 28 Nov 2022 05:31:26 +0000
Subject: [PATCH] lei_mirror: defend against infinite loops

A reference chain of 1000 ought to be enough, I think...
---
 lib/PublicInbox/LeiMirror.pm | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/PublicInbox/LeiMirror.pm b/lib/PublicInbox/LeiMirror.pm
index 0f46d355..1d6ed51c 100644
--- a/lib/PublicInbox/LeiMirror.pm
+++ b/lib/PublicInbox/LeiMirror.pm
@@ -538,9 +538,13 @@ sub clone_all {
 	# resolve references, deepest, first:
 	while (scalar keys %$todo) {
 		for my $x (keys %$todo) {
+			my $nr;
 			# resolve multi-level references
 			while (defined(my $nxt = $m->{$x}->{reference})) {
 				exists($todo->{$nxt}) or last;
+				die <<EOM if ++$nr > 1000;
+E: dependency loop detected (`$x' => `$nxt')
+EOM
 				$x = $nxt;
 			}
 			my $y = delete $todo->{$x} // next; # already done
-- 
2.48.1