fix confused code and redundant checks for fake players, backguard compatibility

* level its not property set on join player due inherit code
* real check player for fake players provided in ch_player function
* do not check fake players in callbacks due performance impack
* the level of the attribute its never set property, was backguard compatibilty part
* closes and fixed https://notabug.org/TenPlus1/stamina/issues/15
* this mod now works with older engines 0.4 and also newer 5.X

init.lua

@@ -24,6 +24,7 @@ STAMINA_STARVE_LVL = 3		-- level of staturation that causes starving
 
 STAMINA_VISUAL_MAX = 20		-- hud bar extends only to 20
 
+local is_50 = minetest.has_feature("object_use_texture_alpha")
 
 local function clamp(val, minval, maxval)
 	return math.max(math.min(val, maxval), minval)
@@ -37,34 +38,36 @@ SPRINT_JUMP  = clamp(tonumber(minetest.settings:get("stamina_sprint_jump")) or 0
 SPRINT_DRAIN  = clamp(tonumber(minetest.settings:get("stamina_sprint_drain")) or 0.35, 0.0, 1.0)
 
 
+local function ck_player(player)
+	-- pipeworks fake player check its not necesary with real player check:
+	if player then if minetest.is_player(player) then return true end end
+	return false
+end
+
 local function get_int_attribute(player)
 
-	-- pipeworks fake player check
+	if not ck_player(player) then return nil end
-	if not player or not player.get_attribute then
+
-		return nil
+	local level
+	if is_50 then
+		local meta = player:get_meta()
+		level = meta and meta:get_string("stamina:level")
+	else
+		level = player and player:get_attribute("stamina:level")
 	end
 
-	local meta = player:get_meta()
+	if level then return tonumber(level) end -- true its converted to number, even false
-	local level = meta and meta:get_string("stamina:level")
-
-	if level then
-		return tonumber(level)
-	end
 
 	return nil
 end
 
-
 local stamina_enabled = minetest.settings:get_bool("enable_stamina") ~= false
 local damage_enabled = minetest.settings:get_bool("enable_damage")
 
 
 local function stamina_update_level(player, level)
 
-	-- pipeworks fake player check
+	if not ck_player(player) then return end
-	if not player.get_attribute or not stamina_enabled then
-		return nil
-	end
 
 	local old = get_int_attribute(player)
 
@@ -77,9 +80,12 @@ local function stamina_update_level(player, level)
 		return
 	end
 
-	local meta = player and player:get_meta() ; if not meta then return end
+	if is_50 then
-
+		local meta = player and player:get_meta() ; if not meta then return end
-	meta:set_string("stamina:level", level)
+		meta:set_string("stamina:level", level)
+	else
+		player:set_attribute("stamina:level", level)
+	end
 
 	player:hud_change(
 		stamina.players[player:get_player_name()].hud_id,
@@ -113,8 +119,7 @@ end
 local function exhaust_player(player, v)
 
 	if not player
-	or not player.is_player
+	or not ck_player(player) -- player.is_player can return nill in rare cases, and real check of player here
-	or not player:is_player()
 	or not player.set_attribute then
 		return
 	end
@@ -151,7 +156,7 @@ local pova_mod = minetest.get_modpath("pova")
 
 local function set_sprinting(name, sprinting)
 
-	local player = minetest.get_player_by_name(name) ; if not player then return end
+	local player = minetest.get_player_by_name(name) ; if not ck_player(player) then return end
 
 	-- get player physics
 	local def = player:get_physics_override()
@@ -217,7 +222,7 @@ end
 
 local function head_particle(player, texture)
 
-	if not player then return end
+	if not ck_player(player) then return end
 
 	local prop = player:get_properties()
 	local eye_height = prop.eye_height or 1.23
@@ -246,7 +251,7 @@ local function drunk_tick()
 
 	for _,player in ipairs(minetest.get_connected_players()) do
 
-		if not player then return end
+		if not ck_player(player) then return end
 
 		local name = player:get_player_name()
 
@@ -295,7 +300,7 @@ local function health_tick()
 
 	for _,player in ipairs(minetest.get_connected_players()) do
 
-		if not player then return end
+		if not ck_player(player) then return end
 
 		local name = player:get_player_name()
 
@@ -331,7 +336,7 @@ local function action_tick()
 
 	for _,player in ipairs(minetest.get_connected_players()) do
 
-		if not player then return end
+		if not ck_player(player) then return end
 		local controls = player:get_player_control()
 
 		-- Determine if the player is walking or jumping
@@ -351,7 +356,7 @@ local function action_tick()
 		--- START sprint
 		if enable_sprint then
 
-			if not player then return end
+			if not ck_player(player) then return end
 			local name = player:get_player_name()
 
 			-- check if player can sprint (stamina must be over 6 points)
@@ -417,7 +422,7 @@ local function poison_tick()
 
 	for _,player in ipairs(minetest.get_connected_players()) do
 
-		if not player then return end
+		if not ck_player(player) then return end
 
 		local name = player:get_player_name()
 
@@ -457,7 +462,7 @@ local function stamina_tick()
 
 	for _,player in ipairs(minetest.get_connected_players()) do
 
-		if not player then return end
+		if not ck_player(player) then return end
 
 		local h = get_int_attribute(player)
 
@@ -512,9 +517,7 @@ if damage_enabled and minetest.settings:get_bool("enable_stamina") ~= false then
 	-- override core.do_item_eat() so we can redirect hp_change to stamina
 	core.do_item_eat = function(hp_change, replace_with_item, itemstack, user, pointed_thing)
 
-		if user.is_fake_player then
+		if not ck_player(user) then return end -- abort if called by fake player (eg. pipeworks-wielder)
-			return -- abort if called by fake player (eg. pipeworks-wielder)
-		end
 
 		local old_itemstack = itemstack
 
@@ -639,17 +642,22 @@ if damage_enabled and minetest.settings:get_bool("enable_stamina") ~= false then
 
 		local level = STAMINA_VISUAL_MAX -- TODO
 
+		-- the code here was redundant cos get_int_attribute already call the level
+		-- but with backguard compat, tenplus1 just inherint the code but with removed backguard compatibility
 		if get_int_attribute(player) then
-
 			level = math.min(get_int_attribute(player), STAMINA_VISUAL_MAX)
-		else
+		end
+		if is_50 then
 			local meta = player:get_meta()
-
+			if meta then meta:set_string("stamina:level", level) end
-			meta:set_string("stamina:level", level)
+		else
+			player:set_attribute("stamina:level", level)
 		end
 
 		local name = player:get_player_name()
 
+		if not name then return end
+
 		local id = player:hud_add({
 			name = "stamina",
 			hud_elem_type = "statbar",
@@ -673,6 +681,7 @@ if damage_enabled and minetest.settings:get_bool("enable_stamina") ~= false then
 
 	minetest.register_on_respawnplayer(function(player)
 
+		if not player then return end
 		local name = player:get_player_name() ; if not name then return end
 
 		if stamina.players[name].poisoned
@@ -691,6 +700,7 @@ if damage_enabled and minetest.settings:get_bool("enable_stamina") ~= false then
 	minetest.register_globalstep(stamina_globaltimer)
 
 	minetest.register_on_placenode(function(pos, oldnode, player, ext)
+		if not player then return end
 		exhaust_player(player, STAMINA_EXHAUST_PLACE)
 	end)