Django模型中的抽象继承，导致MAX递归深度错误 [英] Abstract Inheritance in Django Model, causing MAX recursion depth error

问题描述

我正在尝试使用以下代码在Django中实现抽象继承，但会产生MAX递归深度错误.我正在尝试覆盖模型的save方法.

I'm trying to implement abstract inheritance in Django with the following code, but it produces a MAX recursion depth error. I'm trying to override a model's save method.

class BaseModel(models.Model):
    class Meta:
        abstract = True

    def save(self, *args, **kwargs):
        #i'm doing something here

        #i think the problem is in the return statement specifically because of the
        #self.__class__ expression.
        return super(self.__class__, self).save(*args, **kwargs)

class MyModel(BaseModel):
    p = models.CharField(max_length=30)

产生此错误(跟踪结束，很长):

produces this error (end of the trace, it's lengthy):

  File "/home/jultra/ap3w/jultra_01/mysite/testsite/models.py", line 10, in save
    return super(self.__class__, self).save(*args, **kwargs)
  File "/home/jultra/ap3w/jultra_01/mysite/testsite/models.py", line 10, in save
    return super(self.__class__, self).save(*args, **kwargs)
  File "/home/jultra/ap3w/jultra_01/mysite/testsite/models.py", line 10, in save
    return super(self.__class__, self).save(*args, **kwargs)
  File "/home/jultra/ap3w/jultra_01/mysite/testsite/models.py", line 10, in save
    return super(self.__class__, self).save(*args, **kwargs)
RuntimeError: maximum recursion depth exceeded

推荐答案

不要不要在self.__class__上致电super！在实际的课程上调用它:

Do not call super on self.__class__! Call it on the actual class:

return super(BaseModel, self).save(*args, **kwargs)

这是因为self.__class__始终引用实例的实际具体类.因此，如果您从BaseModel继承MyModel，则当您进入BaseModel中的save方法时，self.__class__仍然是MyModel.因此，它将找到MyModel的超级对象，即BaseModel，因此调用BaseModel中的save，这将再次找到MyModel的超级对象...

This is because self.__class__ always refers to the actual concrete class of the instance. So if you inherit MyModel from BaseModel, when you get to the save method in BaseModel self.__class__ is still MyModel. So it finds the super of MyModel, which is BaseModel, so calls the save in BaseModel, which once again finds the super of MyModel...

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