Extra error checking.

mapgen.lua

@@ -8,9 +8,14 @@ local fortress_noise = {offset = 0, scale = 1, seed = -4082, spread = {x = 7, y
 -- This tables looks up nodes that aren't already stored.
 local node = setmetatable({}, {
 	__index = function(t, k)
+		if not (t and k and type(t) == 'table') then
+			return
+		end
+
 		t[k] = minetest.get_content_id(k)
 		return t[k]
-	end})
+	end
+})
 
 local data = {}
 local p2data = {}  -- vm rotation data buffer
@@ -41,6 +46,10 @@ end
 --end
 
 fun_caves.is_fortress = function(pos, cs)
+	if not pos then
+		return
+	end
+
 	-- Fix this to get csize, somehow.
 	-- Remember that this function may be called
 	--  before any chunks are generated.
@@ -60,6 +69,10 @@ fun_caves.is_fortress = function(pos, cs)
 	local z = math.floor((pos.z + offset) / cs.z)
 
 	local n = minetest.get_perlin(fortress_noise):get3d({x=x, y=y, z=z})
+	if not (n and type(n) == 'number') then
+		return
+	end
+
 	if math.floor((n * 10000) % (fun_caves.DEBUG and 4 or 19)) == 1 then
 		return true
 	end
@@ -68,6 +81,10 @@ fun_caves.is_fortress = function(pos, cs)
 end
 
 fun_caves.place_schematic = function(minp, maxp, data, p2data, area, node, pos, schem, center)
+	if not (minp and maxp and data and p2data and area and node and pos and schem and type(data) == 'table' and type(p2data) == 'table' and type(schem) == 'table') then
+		return
+	end
+
 	local rot = math.random(4) - 1
 	local yslice = {}
 	if schem.yslice_prob then
@@ -119,6 +136,10 @@ fun_caves.place_schematic = function(minp, maxp, data, p2data, area, node, pos,
 end
 
 fun_caves.surround = function(node, data, area, ivm)
+	if not (node and data and area and ivm and type(data) == 'table' and type(ivm) == 'number') then
+		return
+	end
+
 	-- Check to make sure that a plant root is fully surrounded.
 	-- This is due to the kludgy way you have to make water plants
 	--  in minetest, to avoid bubbles.
@@ -345,8 +366,16 @@ fun_caves.cave_biomes = {
 
 
 local function generate(p_minp, p_maxp, seed)
+	if not (p_minp and p_maxp and seed) then
+		return
+	end
+
 	local minp, maxp = p_minp, p_maxp
 	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
+	if not (vm and emin and emax) then
+		return
+	end
+
 	vm:get_data(data)
 	p2data = vm:get_param2_data()
 	local heightmap
@@ -358,7 +387,14 @@ local function generate(p_minp, p_maxp, seed)
 	end
 
 	-- use the same seed (based on perlin noise).
-	math.randomseed(minetest.get_perlin(seed_noise):get2d({x=minp.x, y=minp.z}))
+	do
+		local seed = minetest.get_perlin(seed_noise):get2d({x=minp.x, y=minp.z})
+		if not (seed and type(seed) == 'number') then
+			return
+		end
+
+		math.randomseed(seed)
+	end
 
 	local write = false
 	local write_p2, write_p4 = false, false