Fix for possible nil item in on_player_built_tile

features/gui/paint.lua

@@ -52,7 +52,12 @@ Global.register(
 )
 
 local function player_build_tile(event)
-    if event.item.name ~= brush_tool then
+    local item = event.item
+    if not item then
+        return
+    end
+
+    if item.name ~= brush_tool then
         return
     end
 
@@ -68,8 +73,10 @@ local function player_build_tile(event)
 
     local tiles = event.tiles
     local count = 0
-    for _, tile_data in ipairs(tiles) do
+    for i = 1, #tiles do
+        local tile_data = tiles[i]
         tile_data.name = replace_tile
+
         if tile_data.old_tile.name == replace_tile then
             count = count + 1
         end

map_gen/shared/change_landfill_tile.lua

@@ -8,15 +8,16 @@ Event.add(
     defines.events.on_player_built_tile,
     function(event)
         local item = event.item
-        if not item or not item.valid then
+        if not item then
             return
         end
 
-        if event.item.name == 'landfill' then
+        if item.name == 'landfill' then
             local tiles = event.tiles
             for i = 1, #tiles do
                 tiles[i].name = replacement_tiles[random(1, tile_count)]
             end
+
             local surface = game.surfaces[event.surface_index]
             surface.set_tiles(tiles)
         end

map_gen/shared/restrict_landfill_tile.lua

@@ -6,7 +6,12 @@ global.allowed_landfill_tiles = {}
 Event.add(
     defines.events.on_player_built_tile,
     function(event)
-        local item_name = event.item.name
+        local item = event.item
+        if not item then
+            return
+        end
+
+        local item_name = item.name
         if item_name ~= 'landfill' then
             return
         end