form.cleaned_data is while form handling

Question

It's a really simple form but I don't know where's got wrong. When I check the debug mode of django site, I found that the clean_data of new field is missing, as the picture of following:

class PasswordEditForm(forms.Form):
  old = forms.CharField(widget=forms.PasswordInput, min_length=6,
                      max_length=30, label='舊密碼', label_suffix=' ')
  new = forms.CharField(widget=forms.PasswordInput, min_length=6,
                      max_length=30,  label='新密碼', label_suffix=' ')
  new_confirm = forms.CharField(widget=forms.PasswordInput, min_length=6,
                              max_length=30,  label='再輸入一次', label_suffix=' ')

  def clean_new(self):
    cd = self.cleaned_data
    if cd['old'] == cd['new']:
      raise forms.ValidationError('新密碼與舊密碼相同')
    return cd['new']

  def clean_new_confirm(self):
    cd = self.cleaned_data
    if cd['new'] != cd['new_confirm']:
      raise forms.ValidationError('兩次輸入密碼不相符')
    return cd['new_confirm']

Answer 1

The problem is if you type same new and old password then clean_new method raise exception and return no value. That's why in clean_new_confirm which performed after clean_new cleaned_data is not contains new value.

You can avoid error just using get. Check first if cleaned_data contains new value and if yes, check if new equals to new_confirm:

def clean_new_confirm(self):
    cd = self.cleaned_data
    new_pass = cd.get('new')
    if new_pass and new_pass != cd.get('new_confirm'):
        raise forms.ValidationError('兩次輸入密碼不相符')
    return cd['new_confirm']