Add on_construct function for cart entity

depends.txt

@@ -1,5 +1,6 @@
 default
 tnt
 farming
+carts?
 treasurer?
 mobs_monster?

gameconfig.lua

@@ -23,9 +23,11 @@ tsm_railcorridors.nodes = {
 
 -- List of cart entities. Carts will be placed randomly of the right-hand or left side of
 -- the main rail.
-tsm_railcorridors.carts = {
-	"carts:cart",
-}
+tsm_railcorridors.carts = {}
+
+if minetest.get_modpath("carts") then
+	table.insert(tsm_railcorridors.carts, "carts:cart")
+end
 
 if minetest.get_modpath("mobs_monster") then
 	tsm_railcorridors.nodes.cobweb = "mobs:cobweb"
@@ -42,6 +44,13 @@ end
 function tsm_railcorridors.on_construct_spawner(pos)
 end
 
+-- This is called after a cart has been placed by the game.
+-- Use this to properly set up entity metadata and stuff.
+-- * pos: Position of cart
+-- * cart: Cart entity
+function tsm_railcorridors.on_construct_cart(pos, cart)
+end
+
 -- Fallback function. Returns a random treasure. This function is called for chests
 -- only if the Treasurer mod is not found.
 -- pr: A PseudoRandom object

init.lua

@@ -563,7 +563,10 @@ local function corridor_func(waypoint, coord, sign, up_or_down, up_or_down_next,
 				if placed then
 					local cart_type = pr:next(1, #tsm_railcorridors.carts)
 					-- FIXME: The cart sometimes fails to spawn
-					minetest.add_entity(cpos, tsm_railcorridors.carts[cart_type])
+					local cart = minetest.add_entity(cpos, tsm_railcorridors.carts[cart_type])
+					if cart then
+						tsm_railcorridors.on_construct_cart(cpos, cart)
+					end
 				end
 			end
 		end