util.prosodyctl.check: Fix for net.dns vs unbound API difference net.dns returns nil for NXDOMAIN, while net.unbound returns a table with zero items and various status fields.

author: Kim Alvefur <zash@zash.se>
date: Sun, 20 Jun 2021 17:14:17 +0200
parent: 11612:bc43731b275a
child: 11615:8e16fd976c57
--- a/util/prosodyctl/check.lua	Sun Jun 20 17:11:59 2021 +0200
+++ b/util/prosodyctl/check.lua	Sun Jun 20 17:14:17 2021 +0200
@@ -301,7 +301,7 @@
 			local target_hosts = set.new();
 			if modules:contains("c2s") then
 				local res = dns.lookup("_xmpp-client._tcp."..idna.to_ascii(host)..".", "SRV");
-				if res then
+				if res and #res > 0 then
 					for _, record in ipairs(res) do
 						if record.srv.target == "." then -- TODO is this an error if mod_c2s is enabled?
 							print("    'xmpp-client' service disabled by pointing to '.'"); -- FIXME Explain better what this is
@@ -323,7 +323,7 @@
 			end
 			if modules:contains("s2s") then
 				local res = dns.lookup("_xmpp-server._tcp."..idna.to_ascii(host)..".", "SRV");
-				if res then
+				if res and #res > 0 then
 					for _, record in ipairs(res) do
 						if record.srv.target == "." then -- TODO Is this an error if mod_s2s is enabled?
 							print("    'xmpp-server' service disabled by pointing to '.'"); -- FIXME Explain better what this is