Version 4: Feature checks and deprecate internal functions

callbacks.lua

@@ -14,9 +14,9 @@ end
 minetest.register_on_joinplayer(function(player)
 	local player_name = player:get_player_name()
 	unified_inventory.players[player_name] = {}
-	unified_inventory.current_index[player_name] = 1
+	unified_inventory.current_index[player_name] = 1 -- Item (~page) index
 	unified_inventory.filtered_items_list[player_name] =
-	unified_inventory.items_list
+		unified_inventory.items_list
 	unified_inventory.activefilter[player_name] = ""
 	unified_inventory.active_search_direction[player_name] = "nochange"
 	unified_inventory.apply_filter(player, "", "nochange")
@@ -244,11 +244,8 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 			unified_inventory.current_page[player_name])
 end)
 
-if minetest.delete_detached_inventory then
-	minetest.register_on_leaveplayer(function(player)
-		local player_name = player:get_player_name()
-		minetest.delete_detached_inventory(player_name.."_bags")
-		minetest.delete_detached_inventory(player_name.."craftrecipe")
-		minetest.delete_detached_inventory(player_name.."refill")
-	end)
-end
+minetest.register_on_leaveplayer(function(player)
+	local player_name = player:get_player_name()
+	minetest.remove_detached_inventory(player_name.."_bags")
+	minetest.remove_detached_inventory(player_name.."refill")
+end)

group.lua

@@ -1,30 +1,5 @@
 local S = minetest.get_translator("unified_inventory")
 
-function unified_inventory.canonical_item_spec_matcher(spec)
-	local specname = ItemStack(spec):get_name()
-	if specname:sub(1, 6) ~= "group:" then
-		return function (itemname)
-			return itemname == specname
-		end
-	end
-
-	local group_names = specname:sub(7):split(",")
-	return function (itemname)
-		local itemdef = minetest.registered_items[itemname]
-		for _, group_name in ipairs(group_names) do
-			if (itemdef.groups[group_name] or 0) == 0 then
-				return false
-			end
-		end
-		return true
-	end
-end
-
-function unified_inventory.item_matches_spec(item, spec)
-	local itemname = ItemStack(item):get_name()
-	return unified_inventory.canonical_item_spec_matcher(spec)(itemname)
-end
-
 function unified_inventory.extract_groupnames(groupname)
 	local specname = ItemStack(groupname):get_name()
 	if specname:sub(1, 6) ~= "group:" then
@@ -34,22 +9,6 @@ function unified_inventory.extract_groupnames(groupname)
 	return table.concat(group_names, S(" and ")), #group_names
 end
 
-unified_inventory.registered_group_items = {
-	mesecon_conductor_craftable = "mesecons:wire_00000000_off",
-	stone = "default:cobble",
-	wood = "default:wood",
-	book = "default:book",
-	sand = "default:sand",
-	leaves = "default:leaves",
-	tree = "default:tree",
-	vessel = "vessels:glass_bottle",
-	wool = "wool:white",
-}
-
-function unified_inventory.register_group_item(groupname, itemname)
-	unified_inventory.registered_group_items[groupname] = itemname
-end
-
 
 -- This is used when displaying craft recipes, where an ingredient is
 -- specified by group rather than as a specific item.  A single-item group

init.lua

@@ -1,5 +1,11 @@
 -- Unified Inventory
 
+if not minetest.features.formspec_version_element then
+	-- At least formspec_version[] is the minimal feature requirement
+	error("Unified Inventory requires Minetest version 5.4.0 or newer.\n" ..
+		" Please update Minetest or use an older version of Unified Inventory.")
+end
+
 local modpath = minetest.get_modpath(minetest.get_current_modname())
 local worldpath = minetest.get_worldpath()
 
@@ -46,7 +52,7 @@ unified_inventory = {
 	list_img_offset = 0.13,
 	standard_background = "background9[0,0;1,1;ui_formbg_9_sliced.png;true;16]",
 
-	version = 3
+	version = 4
 }
 
 local ui = unified_inventory
@@ -170,3 +176,4 @@ end
 
 dofile(modpath.."/item_names.lua")
 dofile(modpath.."/waypoints.lua")
+dofile(modpath.."/legacy.lua") -- mod compatibility

internal.lua

@@ -378,3 +378,13 @@ function ui.apply_filter(player, filter, search_dir)
 	ui.active_search_direction[player_name] = search_dir
 	ui.set_inventory_formspec(player, ui.current_page[player_name])
 end
+
+-- Inform players about potential visual issues
+minetest.register_on_joinplayer(function(player)
+	local player_name = player:get_player_name()
+	local info = minetest.get_player_information(player_name)
+	if info and (info.formspec_version or 0) < 4 then
+		minetest.chat_send_player(player_name, S("Unified Inventory: Your game version is too old"
+			.. " and does not support the GUI requirements. You might experience visual issues."))
+	end
+end)

legacy.lua

@@ -0,0 +1,55 @@
+-- Inefficient pattern matching
+
+local warned_funcs = {}
+local function LOG_ONCE(funcname)
+	if warned_funcs[funcname] then return end
+	warned_funcs[funcname] = true
+	minetest.log("error", "Call to undocumented, deprecated API '" .. funcname .. "'."
+		.. " In a future version of Unified Inventory this will result in a real error.")
+end
+
+function unified_inventory.canonical_item_spec_matcher(spec)
+	LOG_ONCE("canonical_item_spec_matcher")
+	local specname = ItemStack(spec):get_name()
+	if specname:sub(1, 6) ~= "group:" then
+		return function (itemname)
+			return itemname == specname
+		end
+	end
+
+	local group_names = specname:sub(7):split(",")
+	return function (itemname)
+		local itemdef = minetest.registered_items[itemname]
+		for _, group_name in ipairs(group_names) do
+			if (itemdef.groups[group_name] or 0) == 0 then
+				return false
+			end
+		end
+		return true
+	end
+end
+
+function unified_inventory.item_matches_spec(item, spec)
+	LOG_ONCE("item_matches_spec")
+	local itemname = ItemStack(item):get_name()
+	return unified_inventory.canonical_item_spec_matcher(spec)(itemname)
+end
+
+
+unified_inventory.registered_group_items = {
+	mesecon_conductor_craftable = "mesecons:wire_00000000_off",
+	stone = "default:cobble",
+	wood = "default:wood",
+	book = "default:book",
+	sand = "default:sand",
+	leaves = "default:leaves",
+	tree = "default:tree",
+	vessel = "vessels:glass_bottle",
+	wool = "wool:white",
+}
+
+function unified_inventory.register_group_item(groupname, itemname)
+	LOG_ONCE("register_group_item")
+	unified_inventory.registered_group_items[groupname] = itemname
+end
+