当用户导入不推荐使用的变量时引发自定义导入错误[重复]

我认为这在Python3.7之前是不可能的。

然而,在Python3.7或更高版本中,这可以通过使用模块级来实现 __getattr__ 加入 PEP562 .

你可以用like so:

#_deprecated_vars is a dict of keys -> alternatives (or None)
_deprecated_vars: Dict[str, Optional[str]] = {
        'deprecated_var': 'from foo.bar import Baz; deprecated_var = Baz()', 
        'other_deprecated_var': None
    }

def __getattr__(name):
    if name in _deprecated_vars:
        alt_text = '{name} was removed from module {__name__}'
        replace_text = _deprecated_vars[name]
        if replace_text is not None:
           alt_text += f'. Replace with {replace_text!r}.'
        raise AttributeError(alt_text)
    raise AttributeError(f"module {__name__} has no attribute {name}")

from a.b import deprecated_var . 这是为了 import a.b; a.b.deprecated_var

对于您的特定示例,可以使用以下命令:

mymodule/__init__.py

#deprecated_var = 5
replacement_var = 6

mymodule/deprecated_var.py :

raise ImportError("deprecated_var is deprecated. Use mypkg.mymodule.replacement_var instead")

当这引起习俗 ImportError 直接导入变量时:

>>> from mymodule import deprecated_var
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../mymodule/deprecated_var.py", line 1, in <module>
    raise ImportError("deprecated_var is deprecated. Use mypkg.mymodule.replacement_var instead")
ImportError: deprecated_var is deprecated. Use mypkg.mymodule.replacement_var instead

AttributeError 而不是弃用警告:

>>> import mymodule
>>> mymodule.deprecated_var
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'mymodule' has no attribute 'deprecated_var'