Why is there a key error in this line of my Django forms code?

class RegisterForm(forms.Form):
    username = forms.CharField(max_length=16, label="Username", required=False)
    password = forms.CharField(max_length=100,widget=forms.PasswordInput, require开发者_JAVA技巧d=False)
    password2 = forms.CharField(max_length=100,widget=forms.PasswordInput, label="Password Again", required=False)
    fullname = forms.CharField(max_length = 100, required=False)
    email = forms.EmailField(max_length=100, required=False)
    def clean_fullname(self):
        if len(self.cleaned_data['fullname']) < 4:
            raise forms.ValidationError("Enter your full name.")
    def clean_email(self):
        if self.cleaned_data['email'].find("@") <= 0:
            raise forms.ValidationError("Enter a valid email address.")
    def clean_username(self):
        if not self.cleaned_data['username']:
            raise forms.ValidationError("Enter a username.")
        try:
            u = User.objects.get(username = self.cleaned_data['username'])
            if u:
                raise forms.ValidationError("Username is taken.")
        except:
            pass
    def clean_password(self):
        if not self.cleaned_data['password']:
            raise forms.ValidationError("Enter a password.")
    def clean_password2(self):
        if not self.cleaned_data['password2']:
            raise forms.ValidationError("Enter your password (again)")

    def clean(self):
        cleaned_data = self.cleaned_data
        password = cleaned_data['password']  <<< There is a key error here anytime I submit a form.
        password2 = cleaned_data['password2']
        if password and password2:
            if password != password2:
                raise forms.ValidationError("Your passwords do not match.")
        return cleaned_data

There's a key error on password = cleaned_data['password']

The reason is because your clean_password function doesn't return anything. Neither does your clean_password2

This is the order of validation:

1. clean_fieldnames
2. clean

clean_password and clean_password2 need to return a value when they are valid.

def clean_password(self):
    if not self.cleaned_data['password']:
        raise forms.ValidationError("Enter a password.")
    return self.cleaned_data['password']

def clean_password2(self):
    if not self.cleaned_data['password2']:
        raise forms.ValidationError("Enter your password (again)")
    return self.cleaned_data['password2']

although the recommended format to save a few keystrokes (especially on longer validation) is...

def clean_password2(self):
    data = self.cleaned_data['password2']
        raise forms.ValidationError("Enter your password (again)")
    return data

Well the short literal answer is that self.cleaned_data is a dict that has no entry with 'password' as a key. Going to the next stage:

Have you tried inspecting self.cleaned_data? Is it missing only a password entry or is it empty? Did you type in a password on the form? What do you expect to be in self.cleaned_data if nothing is typed into the form? What is the basis of your expectation?

I consider it rather suspect that a method whose name is an action verb like "clean" starts working on an attribute named "cleaned_data" instead of "raw_data" or "uncleaned_data" or "unclean_data" or "not_known_to_be_clean_data" ... is this your idea or just Django weirdness?