muc: Allow clients to change multiple affiliations or roles at once (#345)

According to XEP-0045 sections 9.2, 9.5 and 9.8 affiliation lists and role
lists should allow mass-modification. Prosody however would just use the
first entry of the list and ignore the rest. This is fixed by introducing
a `for` loop to `set` stanzas of the respective `muc#admin` namespace.

In order for this loop to work, the error handling was changed a little.
Prosody no longer returns after the first error. Instead, an error reply
is sent for each malformed or otherwise wrong entry, but the loop keeps
going over the other entries. This may lead to multiple error messages
being sent for one client request. A notable exception from this is when
the XML Schema for `muc#admin` requests is violated. In that case the loop
is aborted with an error message to the client.

The change is a bit bigger than that in order to have the loop only for
`set` stanzas without changing the behaviour of the `get` stanzas. This is
now more in line with trunk, where there are separate methods for each
stanza type.

References: #345

1 files changed, 18 insertions, 7 deletions

diff --git a/plugins/muc/muc.lib.lua b/plugins/muc/muc.lib.lua
index 5d8c6df5..4674f323 100644
--- a/plugins/muc/muc.lib.lua
+++ b/plugins/muc/muc.lib.lua
@@ -802,15 +802,17 @@ function room_mt:handle_to_room(origin, stanza) -- presence changes and groupcha
 			local affiliation = self:get_affiliation(actor);
 			local current_nick = self._jid_nick[actor];
 			local role = current_nick and self._occupants[current_nick].role or self:get_default_role(affiliation);
-			local item = stanza.tags[1].tags[1];
-			if item and item.name == "item" then
-				if type == "set" then
+			if type == "set" then
+				local at_least_one_item_provided = false;
+
+				for item in stanza.tags[1]:childtags("item") do
+					at_least_one_item_provided = true;
+
 					local callback = function() origin.send(st.reply(stanza)); end
 					if item.attr.jid then -- Validate provided JID
 						item.attr.jid = jid_prep(item.attr.jid);
 						if not item.attr.jid then
 							origin.send(st.error_reply(stanza, "modify", "jid-malformed"));
-							return;
 						end
 					end
 					if not item.attr.jid and item.attr.nick then -- COMPAT Workaround for Miranda sending 'nick' instead of 'jid' when changing affiliation
@@ -829,8 +831,17 @@ function room_mt:handle_to_room(origin, stanza) -- presence changes and groupcha
 						if not success then origin.send(st.error_reply(stanza, errtype, err)); end
 					else
 						origin.send(st.error_reply(stanza, "cancel", "bad-request"));
+						return;
 					end
-				elseif type == "get" then
+				end
+
+				if not at_least_one_item_provided then
+					origin.send(st.error_reply(stanza, "cancel", "bad-request"));
+					return;
+				end
+			elseif type == "get" then
+				local item = stanza.tags[1].tags[1];
+				if item and item.name == "item" then
 					local _aff = item.attr.affiliation;
 					local _rol = item.attr.role;
 					if _aff and not _rol then
@@ -868,9 +879,9 @@ function room_mt:handle_to_room(origin, stanza) -- presence changes and groupcha
 					else
 						origin.send(st.error_reply(stanza, "cancel", "bad-request"));
 					end
+				else
+					origin.send(st.error_reply(stanza, "cancel", "bad-request"));
 				end
-			elseif type == "set" or type == "get" then
-				origin.send(st.error_reply(stanza, "cancel", "bad-request"));
 			end
 		elseif xmlns == "http://jabber.org/protocol/muc#owner" and (type == "get" or type == "set") and stanza.tags[1].name == "query" then
 			if self:get_affiliation(stanza.attr.from) ~= "owner" then