Add error handling to sunlight checking to prevent crashing and improve diagnosis.

mods/CORE/mcl_util/init.lua

@@ -64,6 +64,24 @@ function mcl_util.check_dtime_timer(self, dtime, timer_name, threshold)
 	return false
 end
 
+-- Minetest 5.3.0 or less can only measure the light level. This came in at 5.4
+-- This function has been known to fail in multiple places so the error handling is added increase safety and improve
+-- debugging. See:
+-- https://git.minetest.land/MineClone2/MineClone2/issues/1392
+function mcl_util.get_natural_light (pos, time)
+	local status, retVal = pcall(minetest.get_natural_light, pos, time)
+	if status then
+		return retVal
+	else
+		minetest.log("warning", "Failed to get natural light at pos: " .. dump(pos) .. ", time: " .. dump(time))
+		if (pos) then
+			local node = minetest.get_node(pos)
+			minetest.log("warning", "Node at pos: " .. dump(node.name))
+		end
+	end
+	return 0
+end
+
 function mcl_util.file_exists(name)
 	if type(name) ~= "string" then return end
 	local f = io.open(name)

mods/ENTITIES/mcl_mobs/physics.lua

@@ -643,7 +643,7 @@ function mob_class:do_env_damage()
 			--minetest.log("warning", "Pos is ignored: " .. dump(pos))
 		end
 
-		local sunlight = minetest.get_natural_light(pos, self.time_of_day)
+		local sunlight = mcl_util.get_natural_light(pos, self.time_of_day)
 
 		if self.light_damage ~= 0 and (sunlight or 0) > 12 then
 			if self:deal_light_damage(pos, self.light_damage) then

mods/ENVIRONMENT/mcl_raids/init.lua

@@ -240,7 +240,7 @@ end
 local function start_firework_rocket(pos)
 	local p = get_point_on_circle(pos,math.random(32,64),32)
 	local n = minetest.get_node(p)
-	local l = minetest.get_natural_light(pos,0.5)
+	local l = mcl_util.get_natural_light(pos,0.5)
 	if n.name ~= "air" or l <= minetest.LIGHT_MAX then return end
 	local o = minetest.add_entity(p,"mcl_bows:rocket_entity")
 	o:get_luaentity()._harmless = true

mods/ENVIRONMENT/mcl_zombie_sieges/init.lua

@@ -1,7 +1,7 @@
 local zombie_siege_enabled = minetest.settings:get_bool("mcl_raids_zombie_siege", false)
 
 local function check_spawn_pos(pos)
-	return minetest.get_natural_light(pos) < 7
+	return mcl_util.get_natural_light(pos) < 7
 end
 
 local function spawn_zombies(self)

mods/ITEMS/REDSTONE/mesecons_solarpanel/init.lua

@@ -35,29 +35,17 @@ local function path_to_sunlight_exists(position, light_level)
 end
 
 local function sunlight_visible(position)
-	local light_level
+	local light_level = mcl_util.get_natural_light (position)
-	-- Minetest 5.4.0+ can measure the daylight level at a position
+	if light_level >= 12 then
-	if nil ~= minetest.get_natural_light then
+		--minetest.log("Light is greater than 12")
-		light_level = minetest.get_natural_light(
+		return true
-			position,
+	else
-			nil
-		)
-		if light_level >= 12 then
-			return true
-		end
-	else -- Minetest 5.3.0 or less can only measure the light level
 		local time = minetest.get_timeofday() * 24000
 		-- only check light level during day
 		if time > 6000 and time < 18000 then
-			light_level = minetest.get_node_light(
+			light_level = minetest.get_node_light(position,	nil)
-				position,
-				nil
-			)
 			if light_level >= 12 then
-				return path_to_sunlight_exists(
+				return path_to_sunlight_exists(position, 12)
-					position,
-					12
-				)
 			end
 		end
 	end