Hi, GLib doc recommends to duplicate Gio.Files when using them from another thread. Is it necessary for APIs that don’t do I/O, like Gio.File.get_relative_path ?

Yes, it is necessary, because those APIs may access private members of the GFile without locking. It’s more about that (for any of the GFile methods) than about being thread-safe with I/O. Being thread-safe with I/O is only one part of concurrency safety with I/O, because as well as other threads yo…