Do not crash with tenplus1's hopper mod

There are multiple hopper mods and not all of them support the set_extra_container_info function,
so the mod crashes now if it is used together with an incompatible hopper mod.

To prevent the crash, execute the code for hopper compatibility if hopper and hopper.set_extra_container_info exist and not if a mod named hopper is installed.

.luacheckrc

@@ -1,2 +1,2 @@
-read_globals = {"minetest", "table", "default", "pipeworks"}
+read_globals = {"minetest", "table", "vector", "default", "hopper", "pipeworks"}
 globals = {"connected_chests"}

init.lua

@@ -1,3 +1,6 @@
+-- for translation
+local S = minetest.get_translator("connected_chests")
+
 -- param_tab maps the x and z offset to a param2 value
 local param_tab = {
 	["-1 0"] = 0,
@@ -136,6 +139,8 @@ end
 connected_chests = {chestdata = chestdata}
 --[[
 connected_chests.register_chest(<original_node>, {
+	description = <string>, -- The name of the connected chest as shown to the
+		-- player, i.e. the node metadata infotext
 	get_formspec = function(metatable, pos)
 		return <formspec_of_big>
 	end,
@@ -156,6 +161,13 @@ function connected_chests.register_chest(fromname, data)
 	data.left = name_left
 	data.right = name_right
 
+	local description = data.description
+	if not description then
+		minetest.log("deprecated",
+			"Missing connected chest description for " .. fromname)
+		description = "Big " .. minetest.registered_nodes[fromname].description
+	end
+
 	-- executed when connecting the chest
 	data.on_connect = function(pu, pa, par, metatable)
 		minetest.add_node(pu, {name=name_left, param2=par})
@@ -164,7 +176,7 @@ function connected_chests.register_chest(fromname, data)
 		if not data.add_open_chest then
 			metatable.fields.formspec = data.get_formspec(metatable, pu)
 		end
-		metatable.fields.infotext = "Big " .. metatable.fields.infotext
+		metatable.fields.infotext = description
 		local meta = minetest.get_meta(pu)
 		meta:from_table(metatable)
 		local inv = meta:get_inventory()
@@ -215,7 +227,7 @@ function connected_chests.register_chest(fromname, data)
 	local inside_texture
 
 
-	chest.description = "Big " .. chest.description
+	chest.description = description
 	chest.groups = table.copy(chest.groups)
 	chest.groups.not_in_creative_inventory = 1
 	chest.legacy_facedir_simple = nil
@@ -365,14 +377,6 @@ function connected_chests.register_chest(fromname, data)
 			end
 		end
 
-		--~ def_opened.tiles[1] = "default_mese.png" -- top, passt
-		--~ def_opened.tiles[2] = "default_wood.png" -- bottom
-		--~ def_opened.tiles[3] = "default_stone.png" -- right and left side or so
-		--~ def_opened.tiles[4] = "default_obsidian.png" -- back side
-
-		--~ def_opened.tiles[5] = "default_cobble.png" -- front side
-		--~ def_opened.tiles[6] = "default_leaves.png" -- inside
-
 		-- fix right side, somehow
 		def_opened.tiles[4] = def_opened.tiles[3]
 		def_opened.tiles[4].name = def_opened.tiles[4].name .. "^[transformFX"
@@ -515,6 +519,7 @@ end)
 local chest_lid_obstructed = default.chest
 	and default.chest.chest_lid_obstructed
 connected_chests.register_chest("default:chest", {
+	description = S("Big Chest"),
 	add_open_chest = true,
 	on_rightclick = function(pos, _, player)
 		minetest.sound_play("default_chest_open",
@@ -556,6 +561,7 @@ connected_chests.register_chest("default:chest", {
 })
 
 connected_chests.register_chest("default:chest_locked", {
+	description = S("Big Locked Chest"),
 	lock = true,
 	add_open_chest = true,
 	on_rightclick = function(pos, _, player)
@@ -618,7 +624,8 @@ if not chest_lid_obstructed then
 				(def.drawtype == "airlike" or
 				def.drawtype == "signlike" or
 				def.drawtype == "torchlike" or
-				(def.drawtype == "nodebox" and def.paramtype2 == "wallmounted")) then
+				(def.drawtype == "nodebox"
+					and def.paramtype2 == "wallmounted")) then
 			return false
 		end
 		return true
@@ -631,7 +638,80 @@ minetest.register_alias("connected_chests:chest_left",
 	"default:chest_connected_left")
 minetest.register_alias("connected_chests:chest_right",
 	"default:chest_connected_right")
-minetest.register_alias("connected_chests:chest_left_locked", "default:chest_locked_connected_left")
-minetest.register_alias("connected_chests:chest_right_locked", "default:chest_locked_connected_right")
-minetest.register_alias("connected_chests:chest_locked_left", "default:chest_locked_connected_left")
-minetest.register_alias("connected_chests:chest_locked_right", "default:chest_locked_connected_right")
+minetest.register_alias("connected_chests:chest_left_locked",
+	"default:chest_locked_connected_left")
+minetest.register_alias("connected_chests:chest_right_locked",
+	"default:chest_locked_connected_right")
+minetest.register_alias("connected_chests:chest_locked_left",
+	"default:chest_locked_connected_left")
+minetest.register_alias("connected_chests:chest_locked_right",
+	"default:chest_locked_connected_right")
+
+if minetest.global_exists("hopper") and hopper.set_extra_container_info then
+	local function get_inventory(chest_right_pos)
+		local node_right = minetest.get_node(chest_right_pos)
+		if node_right.param2 > 3 then
+			-- The right connected chest node has an invalid param2 value
+			-- Cannot determine the inventory
+			return
+		end
+		local x, z = unpack(param_tab2[node_right.param2])
+		local chest_left_pos = {x=chest_right_pos.x+x, y=chest_right_pos.y,
+			z=chest_right_pos.z+z}
+		local node_left = minetest.get_node(chest_left_pos)
+		if node_left.name ~= "default:chest_connected_left"
+		and node_left.name ~= "default:chest_connected_left_open" then
+			minetest.log("error","The left chest is not a chest: " ..
+				node_left.name .. " at " .. vector.to_string(chest_left_pos))
+			return
+		end
+		if node_left.param2 ~= node_right.param2 then
+			minetest.log("error", "The chests are pointing in different " ..
+				"directions: node_left.param2:" .. node_left.param2 ..
+				", node_right.param2:" .. node_right.param2)
+			return
+		end
+		return minetest.get_meta(chest_left_pos):get_inventory()
+	end
+	hopper:add_container({
+		{"top", "default:chest_connected_left", "main"},
+		{"bottom", "default:chest_connected_left", "main"},
+		{"side", "default:chest_connected_left", "main"},
+		{"top", "default:chest_connected_right", "main",
+			get_inventory = get_inventory},
+		{"bottom", "default:chest_connected_right", "main",
+			get_inventory = get_inventory},
+		{"side", "default:chest_connected_right", "main",
+			get_inventory = get_inventory},
+		{"top", "default:chest_connected_left_open", "main"},
+		{"bottom", "default:chest_connected_left_open", "main"},
+		{"side", "default:chest_connected_left_open", "main"},
+		{"top", "default:chest_connected_right_open", "main",
+			get_inventory = get_inventory},
+		{"bottom", "default:chest_connected_right_open", "main",
+			get_inventory = get_inventory},
+		{"side", "default:chest_connected_right_open", "main",
+			get_inventory = get_inventory},
+	})
+	local function set_hopper_param2(hopper_pos, chest_left_pos)
+		local param2_by_offset = {
+			[vector.new(-1, 0, 0):to_string()] = 0,
+			[vector.new( 0, 0, 1):to_string()] = 1,
+			[vector.new( 1, 0, 0):to_string()] = 2,
+			[vector.new( 0, 0,-1):to_string()] = 3,
+		}
+		local hopper_param2 = param2_by_offset[
+			(chest_left_pos - hopper_pos):to_string()]
+		if hopper_param2 then
+			return hopper_param2
+		end
+		local x, z = unpack(
+			param_tab2[minetest.get_node(chest_left_pos).param2])
+		local chest_right_pos = {x=chest_left_pos.x-x, y=chest_left_pos.y,
+			z=chest_left_pos.z-z}
+		return param2_by_offset[(chest_right_pos - hopper_pos):to_string()]
+	end
+	hopper:set_extra_container_info({
+		{"default:chest_connected_left", set_hopper_param2 = set_hopper_param2},
+	})
+end

locale/connected_chests.eo.tr

@@ -0,0 +1,3 @@
+# textdomain: connected_chests
+Big Chest=Kestego
+Big Locked Chest=Ŝlosita kestego

locale/connected_chests.ru.tr

@@ -0,0 +1,3 @@
+# textdomain: connected_chests
+Big Chest=Большой сундук
+Big Locked Chest=Большой запертый сундук

locale/template.txt

@@ -0,0 +1,3 @@
+# textdomain: connected_chests
+Big Chest=
+Big Locked Chest=

mod.conf

@@ -1,3 +1,3 @@
 name = connected_chests
 depends = default
-optional_depends = pipeworks,technic
+optional_depends = pipeworks,technic,hopper