Usage message is displayed when not desired.

使用提供的 fire_bug.py 示例重现该行为，包括链式命令和 --help。首先跟踪 Python Fire 的命令执行和帮助渲染路径；完成的标志是有效命令不再未经请求就打印帮助信息，同时无命令调用和带有 --help 的调用能够提供有用的命令信息。

When I build a class with methods that can be chained (they return self), I find that the "commands" help message is written out even when I provide commands with proper arguments and the commands are executed. Here is the code

from __future__ import annotations
from fire import Fire


class Foo:
    def act(self, x: int) -> Foo:
        """
        Act for some number of minutes.
        Parameters
        ----------
        x : int
            The number of minutes to act.
        """

        print("act", x, "minute(s)")
        return self

    def rest(self, x: int, y: str = "hours") -> Foo:
        """
        Rest for a while.
        Parameters
        ----------
        x : int
            The time to rest.
        y : str
            The units of x. The default is hours.
        """

        print("rest", x, y)
        return self


if __name__ == "__main__":
    Fire(Foo)

If I run this as python fire_bug.py, I get the help output I expect, which is

NAME
    fire_bug.py act 1

SYNOPSIS
    fire_bug.py act 1 COMMAND

COMMANDS
    COMMAND is one of the following:

     act
       Act for some number of minutes.

     rest
       Rest for a while.

If I run this as python fire_bug.py act 1, I unexpectedly get the help output

NAME
    fire_bug.py act 1

SYNOPSIS
    fire_bug.py act 1 COMMAND

COMMANDS
    COMMAND is one of the following:

     act
       Act for some number of minutes.

     rest
       Rest for a while.

followed by the output I expect, which is

act 1 minute(s)

If run this as python fire_bug.py act 1 rest 9, I again unexpectedly get the help output

NAME
    fire_bug.py act 1 rest 9

SYNOPSIS
    fire_bug.py act 1 rest 9 - COMMAND

COMMANDS
    COMMAND is one of the following:

     act
       Act for some number of minutes.

     rest
       Rest for a while.

followed by the output I expect, which is

act 1 minute(s)
rest 9 hours

If I add a __str__ method to the class that returns "\b", I don't get the unexpected messages, but I also don't get a help message if I run python fire_bug.py.

As a general observation, running python fire_bug.py --help does not produce useful output. The output is

NAME
    fire_bug.py

SYNOPSIS
    fire_bug.py -

The output I would expect would be the output I get when I run python fire_bug.py. I am aware that if I have an __init__ method with arguments that the information about those arguments will be displayed, but separating the two sets of information in this way is quite counterintuitive. Both sets of information should be provided when running with no command and when running with only a --help argument.