From 5e2d48708bb2d28a344d2c027fea637a32df0621 Mon Sep 17 00:00:00 2001
From: KJ Tsanaktsidis <kj@kjtsanaktsidis.id.au>
Date: Fri, 24 Nov 2023 15:06:20 +1100
Subject: [PATCH] Catch EPROTONOSUPPORT as a sign of no IPv6 as well (#41)

If IPv6 is disabled inside a freebsd jail, it seems this returns
EPROTONOSUPPORT and not EAFNOSUPPORT. In both cases, we should simply
try some other listed DNS servers.

Fixes [Bug #19928] https://bugs.ruby-lang.org/issues/19928
---
 lib/resolv.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/resolv.rb b/lib/resolv.rb
index 9e83353..0c96ee8 100644
--- a/lib/resolv.rb
+++ b/lib/resolv.rb
@@ -750,7 +750,7 @@ def lazy_initialize
               next if @socks_hash[bind_host]
               begin
                 sock = UDPSocket.new(af)
-              rescue Errno::EAFNOSUPPORT
+              rescue Errno::EAFNOSUPPORT, Errno::EPROTONOSUPPORT
                 next # The kernel doesn't support the address family.
               end
               @socks << sock