util.pubsub: Fix item store resize to "max"

Previously this would end up passing the "max" directly to the
underlying storage.

plugins/mod_pep.lua

@@ -221,6 +221,7 @@ function get_pep_service(username)
 			["access_model"] = "presence";
 			["send_last_published_item"] = "on_sub_and_presence";
 		};
+		max_items = max_max_items;
 
 		autocreate_on_publish = true;
 		autocreate_on_subscribe = false;

plugins/mod_pubsub/mod_pubsub.lua

@@ -224,6 +224,7 @@ function module.load()
 		node_defaults = {
 			["persist_items"] = true;
 		};
+		max_items = max_max_items;
 		nodestore = node_store;
 		itemstore = create_simple_itemstore;
 		broadcaster = simple_broadcast;

spec/util_pubsub_spec.lua

@@ -169,6 +169,26 @@ describe("util.pubsub", function ()
 			}, ret);
 		end);
 
+		it("has a default max_items", function ()
+			assert.truthy(service.config.max_items);
+		end)
+
+		it("changes max_items to max", function ()
+			assert.truthy(service:set_node_config("node", true, { max_items = "max" }));
+		end);
+
+		it("publishes some more items", function()
+			for i = 4, service.config.max_items + 5 do
+				assert.truthy(service:publish("node", true, tostring(i), "item " .. tostring(i)));
+			end
+		end);
+
+		it("should still return only two items", function ()
+			local ok, ret = service:get_items("node", true);
+			assert.truthy(ok);
+			assert.same(service.config.max_items, #ret);
+		end);
+
 	end);
 
 	describe("the thing", function ()

util/pubsub.lua

@@ -5,6 +5,7 @@ local errors = require "util.error";
 local service_mt = {};
 
 local default_config = {
+	max_items = 256;
 	itemstore = function (config, _) return cache.new(config["max_items"]) end;
 	broadcaster = function () end;
 	subscriber_filter = function (subs) return subs end;
@@ -841,7 +842,11 @@ function service:set_node_config(node, actor, new_config) --> ok, err
 		end
 	elseif old_config["max_items"] ~= node_obj.config["max_items"] then
 		if self.data[node] then
-			self.data[node]:resize(self.nodes[node].config["max_items"]);
+			local max_items = self.nodes[node].config["max_items"];
+			if max_items == "max" then
+				max_items = self.config.max_items;
+			end
+			self.data[node]:resize(max_items);
 		end
 	end