Fix fuel recipes not appearing

init.lua

@@ -29,6 +29,7 @@ local show_formspec = core.show_formspec
 local globalstep = core.register_globalstep
 local on_shutdown = core.register_on_shutdown
 local get_players = core.get_connected_players
+local get_craft_result = core.get_craft_result
 local translate = minetest.get_translated_string
 local on_joinplayer = core.register_on_joinplayer
 local get_all_recipes = core.get_all_craft_recipes
@@ -560,6 +561,21 @@ local function get_filtered_items(player, data)
 	return items
 end
 
+local function get_burntime(item)
+	return get_craft_result{method = "fuel", items = {item}}.time
+end
+
+local function cache_fuel(item)
+	local burntime = get_burntime(item)
+	if burntime > 0 then
+		fuel_cache[item] = {
+			type = "fuel",
+			items = {item},
+			burntime = burntime,
+		}
+	end
+end
+
 local function show_item(def)
 	return def and not (def.groups.not_in_craft_guide == 1 or
 		def.groups.not_in_creative_inventory == 1) and
@@ -1514,6 +1530,10 @@ local function get_init_items()
 		if name ~= "" and show_item(def) then
 			cache_drops(name, def.drop)
 
+			if not fuel_cache[name] then
+				cache_fuel(name)
+			end
+
 			if not recipes_cache[name] then
 				cache_recipes(name)
 			end