def METHOD_NAME(self):
    # The incoming() check relies on empty output so configure
    # the repository first to avoid getting extra output.
    git_command = [self.command, "config", "--local", "pull.ff", "only"]
    cmd = self.get_command(git_command, work_dir=self.path,
                           env_vars=self.env, logger=self.logger)
    cmd.execute()
    if cmd.getretcode() != 0 or cmd.getstate() != Command.FINISHED:
        cmd.log_error("failed to configure git pull.ff")