add nil check in armor.damage

* Implements item groups soulbound and cursed:
Soulbound armors respawn with their owner.
Cursed armors cannot be unequipped by the player.
(disabled in creative mode)

* Prevents a cursed armor from getting unequipped by right clicking another piece of armor.

.github/workflows/reference.yml

@@ -11,15 +11,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
     - name: Setup Lua
-      uses: leafo/gh-actions-lua@v8
+      uses: leafo/gh-actions-lua@v10.0.0
       with:
         luaVersion: 5.4
     - name: Setup Lua Rocks
       uses: leafo/gh-actions-luarocks@v4
     - name: Setup LDoc dependencies
-      run: luarocks install --only-deps https://raw.githubusercontent.com/lunarmodules/LDoc/master/ldoc-scm-3.rockspec
+      run: luarocks install --only-deps https://raw.githubusercontent.com/lunarmodules/ldoc/master/rockspecs/ldoc-1.5.0-1.rockspec
     - name: Setup LDoc
       run: git clone --single-branch --branch=custom https://github.com/AntumDeluge/ldoc.git .ldoc/ldoc && chmod +x .ldoc/ldoc/ldoc.lua
     - name: Generate docs

3d_armor/api.lua

@@ -631,6 +631,9 @@ end
 armor.damage = function(self, player, index, stack, use)
 	local old_stack = ItemStack(stack)
 	local worn_armor = armor:get_weared_armor_elements(player)
+	if not worn_armor then
+		return
+	end
 	local armor_worn_cnt = 0
 	for k,v in pairs(worn_armor) do
 		armor_worn_cnt = armor_worn_cnt + 1
@@ -681,6 +684,10 @@ armor.equip = function(self, player, itemstack)
 		for i=1, armor_inv:get_size("armor") do
 			local stack = armor_inv:get_stack("armor", i)
 			if self:get_element(stack:get_name()) == armor_element then
+				--prevents equiping an armor that would unequip a cursed armor.
+				if minetest.get_item_group(stack:get_name(), "cursed") ~= 0 then
+					return itemstack
+				end
 				index = i
 				self:unequip(player, armor_element)
 				break

3d_armor/init.lua

@@ -224,6 +224,11 @@ local function init_player_armor(initplayer)
 			if player:get_player_name() ~= name then
 				return 0
 			end
+			--cursed items cannot be unequiped by the player
+			local is_cursed = minetest.get_item_group(stack:get_name(), "cursed") ~= 0
+			if not minetest.is_creative_enabled(player) and is_cursed then
+				return 0
+			end
 			return stack:get_count()
 		end,
 		allow_move = function(inv, from_list, from_index, to_list, to_index, count, player)
@@ -355,9 +360,12 @@ if armor.config.drop == true or armor.config.destroy == true then
 		for i=1, armor_inv:get_size("armor") do
 			local stack = armor_inv:get_stack("armor", i)
 			if stack:get_count() > 0 then
-				table.insert(drop, stack)
-				armor:run_callbacks("on_unequip", player, i, stack)
-				armor_inv:set_stack("armor", i, nil)
+				--soulbound armors remain equipped after death
+				if minetest.get_item_group(stack:get_name(), "soulbound") == 0 then
+					table.insert(drop, stack)
+					armor:run_callbacks("on_unequip", player, i, stack)
+					armor_inv:set_stack("armor", i, nil)
+				end
 			end
 		end
 		armor:save_armor_inventory(player)
@@ -393,8 +401,8 @@ if armor.config.drop == true or armor.config.destroy == true then
 			end)
 		end
 	end)
-else -- reset un-dropped armor and it's effects
 	minetest.register_on_respawnplayer(function(player)
+		-- reset un-dropped armor and it's effects
 		armor:set_player_armor(player)
 	end)
 end