Harden against unknown nodes

mods/ENTITIES/mcl_minecarts/carts.lua

@@ -56,7 +56,7 @@ local function handle_cart_enter_exit(self, pos, next_dir, event)
 		local check_pos = pos + dir * check[1] + right * check[2] + up * check[3]
 		local node = minetest.get_node(check_pos)
 		local node_def = minetest.registered_nodes[node.name]
-
+		if node_def then
 			-- node-specific hook
 			local hook_name = "_mcl_minecarts_"..event..check[4]
 			local hook = node_def[hook_name]
@@ -66,6 +66,7 @@ local function handle_cart_enter_exit(self, pos, next_dir, event)
 			hook = mcl_minecarts[event..check[4]]
 			if hook then hook(check_pos, self, next_dir, node_def) end
 		end
+	end
 
 	-- Handle cart-specific behaviors
 	local hook = self["_mcl_minecarts_"..event]
@@ -85,11 +86,13 @@ local function handle_cart_node_watches(self, dtime)
 	for _,node_pos in ipairs(watches) do
 		local node = minetest.get_node(node_pos)
 		local node_def = minetest.registered_nodes[node.name]
+		if node_def then
 			local hook = node_def._mcl_minecarts_node_on_step
 			if hook and hook(node_pos, self, dtime) then
 				new_watches[#new_watches+1] = node_pos
 			end
 		end
+	end
 
 	staticdata.node_watches = new_watches
 end
@@ -197,11 +200,9 @@ local function calculate_acceleration(self, staticdata)
 		acceleration = 0.6
 	elseif staticdata.velocity >= ( node_def._max_acceleration_velocity or max_vel ) then
 		-- Standard friction
-	else
+	elseif node_def and node_def._rail_acceleration then
-		if node_def._rail_acceleration then
 		acceleration = node_def._rail_acceleration * 4
 	end
-	end
 
 	-- Factor in gravity after everything else
 	local gravity_strength = 2.45 --friction * 5
@@ -860,11 +861,9 @@ function mcl_minecarts.place_minecart(itemstack, pointed_thing, placer)
 end
 
 local function dropper_place_minecart(dropitem, pos)
-	local node = minetest.get_node(pos)
-	local nodedef = minetest.registered_nodes[node.name]
-
 	-- Don't try to place the minecart if pos isn't a rail
-	if (nodedef.groups.rail or 0) == 0 then return false end
+	local node = minetest.get_node(pos)
+	if minetest.get_item_group(node.name, "rail") == 0 then return false end
 
 	mcl_minecarts.place_minecart(dropitem, {
 		above = pos,

mods/ENTITIES/mcl_minecarts/functions.lua

@@ -207,8 +207,8 @@ local function update_rail_connections(pos, opt)
 
 	local node = minetest.get_node(pos)
 	local nodedef = minetest.registered_nodes[node.name]
-	if not nodedef._mcl_minecarts then
+	if not nodedef or not nodedef._mcl_minecarts then
-		minetest.log("warning", "attemting to rail connect "..node.name)
+		minetest.log("warning", "attemting to rail connect to "..node.name)
 		return
 	end