Question

On page 168, there are two pieces of code :

def clean_password2(self):
   if self.cleaned_data['password1'] != self.cleaned_data['password2']:
      raise forms.ValidationError("You must type the same password each time")
   return self.cleaned_data['password2']

def clean(self):
   if 'password1' in self.cleaned_data and 'password2' in self.cleaned_data:
      if self.cleaned_data['password1'] != self.cleaned_data['password2']:
         raise forms.ValidationError("You must type the same password each time")
   return self.cleaned_data

In the second case, the code checks whether ‘password1’ and ‘password2’ have any value. In the first case, there is no such check. Why ?

Answer 1

In clean_password2 you are validating the password2 field so you are certain that it exists on that form and don’t need to check for the existence of it in self.cleaned_data. That doesn’t mean they couldn’t also check for the eixstence of password1, however.

The clean method is validating the whole form and has no guarantees of what is present.