Add require_protection and node_ownership_legacy settings

require_protection: Disallows interactions outside of owned areas
node_ownership_legacy: Skip 9+ year old compatibility code by default

interact.lua

@@ -9,11 +9,20 @@ function minetest.is_protected(pos, name)
 end
 
 minetest.register_on_protection_violation(function(pos, name)
-	if not areas:canInteract(pos, name) then
-		local owners = areas:getNodeOwners(pos)
-		minetest.chat_send_player(name,
-			S("@1 is protected by @2.",
-				minetest.pos_to_string(pos),
-				table.concat(owners, ", ")))
+	if areas:canInteract(pos, name) then
+		return
 	end
+
+	local owners = areas:getNodeOwners(pos)
+	if #owners == 0 then
+		-- When require_protection=true
+		minetest.chat_send_player(name,
+			S("@1 may not be accessed.",
+				minetest.pos_to_string(pos)))
+		return
+	end
+	minetest.chat_send_player(name,
+		S("@1 is protected by @2.",
+			minetest.pos_to_string(pos),
+			table.concat(owners, ", ")))
 end)