Don't crash on nil-player in can_dig and check the right players for attachment in chairs.

handlers/animations.lua

@@ -40,13 +40,9 @@ function xdecor.sit(pos, node, clicker, pointed_thing)
 	end
 end
 
-function xdecor.sit_dig(pos, player)
-	local pname = player:get_player_name()
-	local objs = minetest.get_objects_inside_radius(pos, 0.1)
-
-	for _, p in pairs(objs) do
-		if not player or not player:is_player() or p:get_player_name() or
-				default.player_attached[pname] then
+function xdecor.sit_dig(pos, digger)
+	for _, player in pairs(minetest.get_objects_inside_radius(pos, 0.1)) do
+		if player:is_player() and default.player_attached[player:get_player_name()] then
 			return false
 		end
 	end

itemframe.lua

@@ -94,10 +94,10 @@ end
 
 function itemframe.dig(pos, player)
 	local meta = minetest.get_meta(pos)
-	local pname = player:get_player_name()
+	local pname = player and player:get_player_name()
 	local owner = meta:get_string("owner")
 
-	return player and pname == owner
+	return pname == owner
 end
 
 xdecor.register("itemframe", {

mailbox.lua

@@ -78,10 +78,10 @@ end
 function mailbox.dig(pos, player)
 	local meta = minetest.get_meta(pos)
 	local owner = meta:get_string("owner")
-	local player_name = player:get_player_name()
+	local player_name = player and player:get_player_name()
 	local inv = meta:get_inventory()
 
-	return inv:is_empty("mailbox") and player and player_name == owner
+	return inv:is_empty("mailbox") and player_name == owner
 end
 
 function mailbox.after_place_node(pos, placer)