Merge pull request 'Prevent mob conversion code from crashing' (#4421) from teknomunk/MineClone2:fix-conversion-crash into master

Reviewed-on: VoxeLibre/VoxeLibre#4421
Reviewed-by: the-real-herowl <the-real-herowl@noreply.git.minetest.land>

mods/ENTITIES/mcl_mobs/api.lua

@@ -150,6 +150,11 @@ function mob_class:mob_activate(staticdata, def, dtime)
 	local tmp = minetest.deserialize(staticdata)
 
 	if tmp then
+		-- Patch incorrectly converted mobs
+		if tmp.base_mesh ~= minetest.registered_entities[self.name].mesh then
+			mcl_mobs.strip_staticdata(tmp)
+		end
+
 		for _,stat in pairs(tmp) do
 			self[_] = stat
 		end

mods/ENTITIES/mcl_mobs/init.lua

@@ -342,13 +342,33 @@ function mcl_mobs.register_mob(name, def)
 	minetest.register_entity(name, setmetatable(final_def,mcl_mobs.mob_class_meta))
 end -- END mcl_mobs.register_mob function
 
+
+local STRIP_FIELDS = { "mesh", "base_size", "textures", "base_mesh", "base_texture" }
+function mcl_mobs.strip_staticdata(unpacked_staticdata)
+	-- Strip select fields from the staticdata to prevent conversion issues
+	for i = 1,#STRIP_FIELDS do
+		unpacked_staticdata[STRIP_FIELDS[i]] = nil
+	end
+end
 function mcl_mobs.register_conversion(old_name, new_name)
 	minetest.register_entity(old_name, {
 		on_activate = function(self, staticdata, dtime)
-			local obj = minetest.add_entity(self.object:get_pos(), new_name, staticdata)
+			local unpacked_staticdata = minetest.deserialize(staticdata)
-			local hook = (obj:get_luaentity() or {})._on_after_convert
+			mcl_mobs.strip_staticdata(unpacked_staticdata)
-			if hook then hook(obj) end
+			staticdata = minetest.serialize(unpacked_staticdata)
-			self.object:remove()
+
+			local old_object = self.object
+			if not old_object then return end
+
+			local pos = old_object:get_pos()
+			if not pos then return end
+			old_object:remove()
+
+			local new_object = minetest.add_entity(pos, new_name, staticdata)
+			if not new_object then return end
+
+			local hook = (new_object:get_luaentity() or {})._on_after_convert
+			if hook then hook(new_object) end
 		end,
 		_convert_to = new_name,
 	})
@@ -572,7 +592,12 @@ function mcl_mobs.register_egg(mob, desc, background_color, overlay_color, addeg
 					--minetest.log("min light: " .. mob_light_lvl[1])
 					--minetest.log("max light: " .. mob_light_lvl[2])
 
-					mcl_mobspawners.setup_spawner(pointed_thing.under, itemstack:get_name(), mob_light_lvl[1], mob_light_lvl[2])
+					-- Handle egg conversion
+					local mob_name = itemstack:get_name()
+					local convert_to = (minetest.registered_entities[mob_name] or {})._convert_to
+					if convert_to then mob_name = convert_to end
+
+					mcl_mobspawners.setup_spawner(pointed_thing.under, mob_name, mob_light_lvl[1], mob_light_lvl[2])
 					if not minetest.is_creative_enabled(name) then
 						itemstack:take_item()
 					end

mods/ITEMS/mcl_mobspawners/init.lua

@@ -83,6 +83,13 @@ local function respawn_doll(pos)
 	local mob = meta:get_string("Mob")
 	local doll
 	if mob and mob ~= "" then
+		-- Handle conversion of mob spawners
+		local convert_to = (minetest.registered_entities[mob] or {})._convert_to
+		if convert_to then
+			mob = convert_to
+			meta:set_string("Mob", mob)
+		end
+
 		doll = find_doll(pos)
 		if not doll then
 			doll = spawn_doll(pos)
@@ -128,7 +135,6 @@ function mcl_mobspawners.setup_spawner(pos, Mob, MinLight, MaxLight, MaxMobsInAr
 	end
 	set_doll_properties(doll, Mob)
 
-
 	-- Start spawning very soon
 	local t = minetest.get_node_timer(pos)
 	t:start(2)
@@ -165,7 +171,6 @@ local function spawn_mobs(pos, elapsed)
 	local count = 0
 	local ent
 
-
 	local timer = minetest.get_node_timer(pos)
 
 	-- spawn mob if player detected and in range
@@ -367,7 +372,6 @@ doll_def.on_activate = function(self, staticdata, dtime_s)
 	self.object:set_velocity({x=0, y=0, z=0})
 	self.object:set_acceleration({x=0, y=0, z=0})
 	self.object:set_armor_groups({immortal=1})
-
 end
 
 doll_def.on_step = function(self, dtime)