Add basic validation for moving items into the table's slots

table.lua

@@ -459,16 +459,52 @@ minetest.register_on_player_receive_fields(function(player, name, fields)
     end
 end);
 
+-- Called after a table is placed. Sets up the table's inventory and metadata.
+-- pos: The node's position
 local function setup_table_node(pos)
-        local meta = minetest.get_meta(pos);
-        meta:get_inventory():set_size("input", 1);
-        meta:get_inventory():set_size("output", 1);
-        meta:get_inventory():set_size("copy_input", 1);
-        meta:get_inventory():set_size("copy_output", 1);
+    local meta = minetest.get_meta(pos);
+    meta:get_inventory():set_size("input", 1);
+    meta:get_inventory():set_size("output", 1);
+    meta:get_inventory():set_size("copy_input", 1);
+    meta:get_inventory():set_size("copy_output", 1);
 
-        meta:set_int("size", SIZE_SMALL);
-        meta:set_int("scale", SCALE_SMALL);
-        meta:set_int("detail", 0);
+    meta:set_int("size", SIZE_SMALL);
+    meta:set_int("scale", SCALE_SMALL);
+    meta:set_int("detail", 0);
+end
+
+-- Called when the player tries to put an item into one of the table's
+-- inventories.
+-- listname: The name of the inventory the item is being placed in.
+-- stack: The itemstack
+--
+-- Returns 0 if the place is invalid; otherwise, returns the number of items
+-- that can be placed.
+local function table_can_put(_, listname, _, stack, _)
+    if listname == "copy_output" then
+        return 0;
+    end
+
+    if stack:get_name() ~= "cartographer:map" and (listname == "output" or listname == "copy_input") then
+        return 0;
+    end
+
+    return stack:get_count();
+end
+
+-- Called when the player tries to move an item between two of the table's
+-- inventories.
+-- to_list: The name of the inventory the item is being placed in.
+-- count: The number of items being moved
+--
+-- Returns 0 if the move is invalid; otherwise, returns the number of items
+-- that can be moved.
+local function table_can_move(_, _, _, to_list, _, count, _)
+    if to_list == "copy_output" then
+        return 0;
+    end
+
+    return count;
 end
 
 minetest.register_node("cartographer:simple_table", {
@@ -501,6 +537,9 @@ minetest.register_node("cartographer:simple_table", {
     end,
 
     after_place_node = setup_table_node,
+
+    allow_metadata_inventory_move = table_can_move,
+    allow_metadata_inventory_put = table_can_put,
 });
 
 minetest.register_node("cartographer:standard_table", {
@@ -533,6 +572,9 @@ minetest.register_node("cartographer:standard_table", {
     end,
 
     after_place_node = setup_table_node,
+
+    allow_metadata_inventory_move = table_can_move,
+    allow_metadata_inventory_put = table_can_put,
 });
 
 minetest.register_node("cartographer:advanced_table", {
@@ -565,6 +607,9 @@ minetest.register_node("cartographer:advanced_table", {
     end,
 
     after_place_node = setup_table_node,
+
+    allow_metadata_inventory_move = table_can_move,
+    allow_metadata_inventory_put = table_can_put,
 });
 
 function cartographer.register_map_material_name(name, material, value)