perl-net-dns-resolver-programmable used the undocumented and internal
method Net::DNS::rcodesbyname [0], and that interface is no longer
exposed.

This patch, copied from [1], makes the program check for the existence
of the method before trying to use it.

[0]
<https://rt.cpan.org/Public/Bug/Display.html?id=95901>

[1]
<https://rt.cpan.org/Public/Bug/Display.html?id=95901#txn-1575108>

diff --git a/lib/Net/DNS/Resolver/Programmable.pm b/lib/Net/DNS/Resolver/Programmable.pm
index 1af72ce..e09a2f0 100644
--- a/lib/Net/DNS/Resolver/Programmable.pm
+++ b/lib/Net/DNS/Resolver/Programmable.pm
@@ -203,8 +203,10 @@ sub send {
     if (defined(my $resolver_code = $self->{resolver_code})) {
         ($result, $aa, @answer_rrs) = $resolver_code->($domain, $rr_type, $class);
     }
-    
-    if (not defined($result) or defined($Net::DNS::rcodesbyname{$result})) {
+
+    if (not defined($result)
+         or defined($Net::DNS::Parameters::rcodebyname{$result})
+         or defined($Net::DNS::rcodesbyname{$result})) {
         # Valid RCODE, return a packet:
         
         $aa     = TRUE      if not defined($aa);
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