nsupdate: fix 'index out of range' error when no TTL answer is given (#…

…7219)

* nsupdate: fix 'index out of range' error when no TTL answer is given

Fix a possible `list index out of range` when no answer is returned in the `ttl_changed` method
by applying the existing workaround for NS records to all record types.

Resolves #836

* fixup! nsupdate: fix 'index out of range' error when no TTL answer is given

changelogs/fragments/7219-fix-nsupdate-cname.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - nsupdate - fix a possible ``list index out of range`` exception (https://github.com/ansible-collections/community.general/issues/836).

plugins/modules/nsupdate.py

@@ -467,10 +467,8 @@ def ttl_changed(self):
         if lookup.rcode() != dns.rcode.NOERROR:
             self.module.fail_json(msg='Failed to lookup TTL of existing matching record.')
 
-        if self.module.params['type'] == 'NS':
-            current_ttl = lookup.answer[0].ttl if lookup.answer else lookup.authority[0].ttl
-        else:
-            current_ttl = lookup.answer[0].ttl
+        current_ttl = lookup.answer[0].ttl if lookup.answer else lookup.authority[0].ttl
+
         return current_ttl != self.module.params['ttl']