Don't throw exception when variable is undefined

[famedly-bot]

In GitLab by @jcgruenhage on Dec 14, 2022, 13:02

I've tried rolling out with a variable undefined, which meant that a DNS records had no address. I could't figure out what the concrete problem was until later, because the module just completely refused operation with a less than helpful stacktrace:

The full traceback is:
Traceback (most recent call last):
  File "/home/jcgruenhage/.ansible/tmp/ansible-tmp-1671018808.3882365-10237-223587720065386/AnsiballZ_update.py", line 107, in <module>
    _ansiballz_main()
  File "/home/jcgruenhage/.ansible/tmp/ansible-tmp-1671018808.3882365-10237-223587720065386/AnsiballZ_update.py", line 99, in _ansiballz_main
    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)
  File "/home/jcgruenhage/.ansible/tmp/ansible-tmp-1671018808.3882365-10237-223587720065386/AnsiballZ_update.py", line 47, in invoke_module
    runpy.run_module(mod_name='ansible_collections.famedly.dns.plugins.modules.update', init_globals=dict(_module_fqn='ansible_collections.famedly.dns.plugins.modules.update', _modlib_path=modlib_path),
  File "<frozen runpy>", line 226, in run_module
  File "<frozen runpy>", line 98, in _run_module_code
  File "<frozen runpy>", line 88, in _run_code
  File "/tmp/ansible_famedly.dns.update_payload_qu9uu6zd/ansible_famedly.dns.update_payload.zip/ansible_collections/famedly/dns/plugins/modules/update.py", line 180, in <module>
  File "/tmp/ansible_famedly.dns.update_payload_qu9uu6zd/ansible_famedly.dns.update_payload.zip/ansible_collections/famedly/dns/plugins/modules/update.py", line 152, in main
  File "/tmp/ansible_famedly.dns.update_payload_qu9uu6zd/ansible_famedly.dns.update_payload.zip/ansible_collections/famedly/dns/plugins/module_utils/dnsupdate_utils.py", line 67, in send_dns_update_message
  File "/usr/lib/python3.11/site-packages/dns/update.py", line 168, in add
    self._add(False, self.update, name, *args)
  File "/usr/lib/python3.11/site-packages/dns/update.py", line 151, in _add
    rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/dns/rdata.py", line 613, in from_text
    rdata = cls.from_text(rdclass, rdtype, tok, origin, relativize,
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/dns/rdtypes/IN/AAAA.py", line 42, in from_text
    address = tok.get_identifier()
              ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/dns/tokenizer.py", line 581, in get_identifier
    raise dns.exception.SyntaxError('expecting an identifier')
dns.exception.SyntaxError: expecting an identifier