traitlets.config.application:Application._handle_argcomplete_for_subcommand

Extended Summary

argcomplete does not know that traitlets has already consumed subcommands, as it only "sees" the final argparse.ArgumentParser that is constructed. (Indeed KVArgParseConfigLoader does not get passed subcommands at all currently.) We explicitly manipulate the environment variables used internally by argcomplete to get it to skip over the subcommand tokens.