当用户想在Python中使用import *导入所有内容时，如何引发异常？

Question

I want to inhibit user from importing like this:

from module.sub import *

This should raise and exception and do not let anything come in the namespace unless user imports anything specific like this:

from module.sub import apples

Answer 1

In module.sub :

__all__ = []

It won't raise an exception, but when someone does from module.sub import * , nothing will be imported module.sub will still be initialized, added to sys.modules , and added to the local namespace, but none of the names defined in module.sub will be added to the namespace.

You could then refer to module.sub.apples but not apples directly.

---

If you really want an exception, at the cost of being a bit confusing, you could do:

__all__ = ['not_defined']

then:

>>> from module.sub import *
Traceback (most recent call last):
  File "<input>", line 1, in <module>
AttributeError: 'module' object has no attribute 'not_defined'

Answer 2

Luckily the nice folks made python open source so you can certainly do this

download the appropriate source here https://www.python.org/downloads/source/

modify import.c , so that it raises an error if it gets the splat...

or modify the Grammar to ignore the splat (which will require also changing the Parser

once you do one of those things simply recompile python and use your new python instead of the standard one (simply recompile may be a bit misleading on the complexity of this step)

OR MORE SIMPLY JUST USE __ALL__ = [] in your modules __init__.py