Return SOA/NXDOMAIN when the answer is empty

[42wim]

When a service has A records and no AAAA records (or vice versa), also return SOA and NXDOMAIN when asking for the AAAA records. (wrt RFC2308 and negative caching)

See PR #995 for more info

[ryanuber]

I'm a little out of context here - but it appears this is already handled starting at line 504. Are there additional edge cases that this patches up?

I'd also like to see some test code for this to make sure we are covered and to clarify what we are fixing.

[42wim]

(it's not really an edge case in a dual-stack/ipv6 world :-)
At line 504 it only handles the service 'globally'.

The problem is when you ask for the IN A (and there is only an IN AAAA record) or the IN AAAA (and there is only an IN A record) of the service.

For example, you've got a service with only an IPv4 address: test.service.consul IN A 1.2.3.4
Now if you do

dig IN AAAA test.service.consul

It will pass line 504, cause you've got a service node (ipv4 with IN A 1.2.3.4), but the service node has no IPv6 addresses. (which means the resp.Answer will be 0). If that's the case, you will also need to respond with SOA/NXDOMAIN.

Let me know if this clarifies the issue

[42wim]

Added a test for the fix

[ryanbreen]

LGTM!