mod_roster_command: Fix subscription when the "user JID" is a bare domain. Do not attempt to update the roster when the user is bare domain (e.g. a component), since they don't have rosters and the attempt results in an error: $ prosodyctl mod_roster_command subscribe proxy.example.com contact@example.com xxxxxxxxxxFailed to execute command: Error: /usr/lib/prosody/core/rostermanager.lua:104: attempt to concatenate local 'username' (a nil value) stack traceback: /usr/lib/prosody/core/rostermanager.lua:104: in function 'load_roster' /usr/lib/prosody/core/rostermanager.lua:305: in function 'set_contact_pending_out' mod_roster_command.lua:44: in function 'subscribe'

local st = require"util.stanza";
local datetime = require"util.datetime";

local presence = st.presence({ from = module.host })
	:tag("delay", { xmlns = "urn:xmpp:delay",
		stamp = datetime.datetime(prosody.start_time) });

module:hook("presence/host", function(event)
	local stanza = event.stanza;
	if stanza.attr.type == "probe" then
		presence.attr.id = stanza.attr.id;
		presence.attr.to = stanza.attr.from;
		module:send(presence);
		return true;
	end
end, 10);