django - Django Model中的抽象继承，导致MAX递归深度错误

Question

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

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):

  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

Answer 1

做 不是 调用 super在 self.__class__ !在实际类上调用它:

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

这是因为 self.__class__总是指实例的实际具体类。所以如果你继承MyModel来自 BaseModel ，当您到达 save 时BaseModel 中的方法self.__class__还在MyModel .于是找到了MyModel的super，也就是BaseModel，于是调用了BaseModel中的save，又一次找到了MyModel的super……