Clean-up `set_string(..., nil)` usage (fixes #4639) (#4641)

Reviewed-on: VoxeLibre/VoxeLibre#4641
Reviewed-by: kno10 <kno10@noreply.git.minetest.land>
Co-authored-by: Mikita Wiśniewski <rudzik8@protonmail.com>
Co-committed-by: Mikita Wiśniewski <rudzik8@protonmail.com>

mods/ENTITIES/mobs_mc/villager.lua

@@ -818,7 +818,7 @@ local function find_closest_bed (self)
 
 			if (owned_by and owned_by == self._id) then
 				mcl_log("Clear as already owned by me.")
-				bed_meta:set_string("villager", nil)
+				bed_meta:set_string("villager", "")
 				owned_by = nil
 			end
 
@@ -1279,7 +1279,7 @@ local function validate_jobsite(self)
 		mcl_log("Jobsite far, so resettle: " .. tostring(resettle))
 		if resettle then
 			local m = minetest.get_meta(self._jobsite)
-			m:set_string("villager", nil)
+			m:set_string("villager", "")
 			remove_job (self)
 			return false
 		end
@@ -1421,7 +1421,7 @@ local function validate_bed(self)
 	mcl_log("Bed far, so resettle: " .. tostring(resettle))
 	if resettle then
 		mcl_log("Resettled. Ditch bed.")
-		m:set_string("villager", nil)
+		m:set_string("villager", "")
 		self._bed = nil
 		bed_valid = false
 		return false
@@ -1431,7 +1431,7 @@ local function validate_bed(self)
 	mcl_log("Player owner: " .. owned_by_player)
 	if owned_by_player ~= "" then
 		mcl_log("Player owns this. Villager won't take this.")
-		m:set_string("villager", nil)
+		m:set_string("villager", "")
 		self._bed = nil
 		bed_valid = false
 		return false
@@ -2300,13 +2300,13 @@ mcl_mobs.register_mob("mobs_mc:villager", {
 		local bed = self._bed
 		if bed then
 			local bed_meta = minetest.get_meta(bed)
-			bed_meta:set_string("villager", nil)
+			bed_meta:set_string("villager", "")
 			mcl_log("Died, so bye bye bed")
 		end
 		local jobsite = self._jobsite
 		if jobsite then
 			local jobsite_meta = minetest.get_meta(jobsite)
-			jobsite_meta:set_string("villager", nil)
+			jobsite_meta:set_string("villager", "")
 			mcl_log("Died, so bye bye jobsite")
 		end
 

mods/ITEMS/mcl_campfires/api.lua

@@ -39,9 +39,9 @@ local function drop_items(pos, node, oldmeta)
 				if food_entity:get_luaentity().name == "mcl_campfires:food_entity" then
 					food_entity:remove()
 					for i = 1, 4 do
-						meta:set_string("food_x_"..tostring(i), nil)
-						meta:set_string("food_y_"..tostring(i), nil)
-						meta:set_string("food_z_"..tostring(i), nil)
+						meta:set_string("food_x_"..tostring(i), "")
+						meta:set_string("food_y_"..tostring(i), "")
+						meta:set_string("food_z_"..tostring(i), "")
 					end
 				end
 			end
@@ -135,9 +135,9 @@ function mcl_campfires.cook_item(pos, elapsed)
 				if cooked then
 					if food_entity then
 						food_entity:remove() -- Remove visual food entity
-						meta:set_string("food_x_"..tostring(i), nil)
-						meta:set_string("food_y_"..tostring(i), nil)
-						meta:set_string("food_z_"..tostring(i), nil)
+						meta:set_string("food_x_"..tostring(i), "")
+						meta:set_string("food_y_"..tostring(i), "")
+						meta:set_string("food_z_"..tostring(i), "")
 						minetest.add_item(pos, cooked.item) -- Drop Cooked Item
 						-- Throw some Experience Points because why not?
 						-- Food is cooked, xp is deserved for using this unique cooking method. Take that Minecraft ;)

mods/ITEMS/mcl_stonecutter/init.lua

@@ -279,7 +279,6 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	for field_name, value in pairs(fields) do
 		if field_name ~= "scroll" then
 			local itemname = fieldname_to_itemname(field_name)
-			player:get_meta():set_string("mcl_stonecutter:selected", itemname)
 			set_selected_item(player, itemname)
 			update_stonecutter_slots(player)
 			mcl_stonecutter.show_stonecutter_form(player)

mods/PLAYER/mcl_spawn/init.lua

@@ -453,7 +453,7 @@ function mcl_spawn.set_spawn_pos(player, pos, message)
 			-- Pass in villager as arg. Shouldn't know about villagers
 			if bed_bottom_meta then
 				mcl_log("Removing villager from bed bottom meta")
-				bed_bottom_meta:set_string("villager", nil)
+				bed_bottom_meta:set_string("villager", "")
 			else
 				mcl_log("Cannot remove villager from bed bottom meta")
 			end