Fix node replacement in not-quite-loaded chunks

When first entering an area, sometimes placing nodes replaces other nodes that are not buildable_to. This seems to be caused by the fact that nodes in unloaded map blocks are treated as ignore, a node that is buildable_to. This fixes that, by using get_node_or_nil() instead of the previously-used get_node(), then checking to see if the nodes were actually loaded before replacing.

diff --git a/builtin/item.lua b/builtin/item.lua
index 1349fdf63834d133bbb0cf46a5ce22c5a1cc8065..8e2f75a1a2a806ffed887f3a4e98631af32f796e 100644 (file)
--- a/builtin/item.lua
+++ b/builtin/item.lua
@@ -129,11 +129,18 @@ function minetest.item_place_node(itemstack, placer, pointed_thing)
        end
 
        local under = pointed_thing.under
-       local oldnode_under = minetest.env:get_node(under)
+       local oldnode_under = minetest.env:get_node_or_nil(under)
+       local above = pointed_thing.above
+       local oldnode_above = minetest.env:get_node_or_nil(above)
+
+       if not oldnode_under or not oldnode_above then
+               minetest.log("info", placer:get_player_name() .. " tried to place"
+                       .. " node in unloaded position " .. minetest.pos_to_string(above))
+               return itemstack
+       end
+
        local olddef_under = ItemStack({name=oldnode_under.name}):get_definition()
        olddef_under = olddef_under or minetest.nodedef_default
-       local above = pointed_thing.above
-       local oldnode_above = minetest.env:get_node(above)
        local olddef_above = ItemStack({name=oldnode_above.name}):get_definition()
        olddef_above = olddef_above or minetest.nodedef_default