copy_needed_files may fail if the destination directory is otherwise empty.

[jacobfnl]

This will happen if a directory is ignored, yet copy needed files includes a file in that directory.

django_project/
├── ignored_directory/
│   └── file_needed.py
├── app/
│   └── compiled_file.py
└── manage.py

compiled_file gets compiled, manage.py gets copied, but file_needed.py does not. FileNotFoundError exception