django - Inject errors into already validated form?

Question

After my form.Form validates the user input values I pass them to a separate (external) process for further processing. This external process can potentially find further errors in the values.

Is there a way to inject these errors into the already validated form so they can be displayed via the usual form error display methods (or are there better alternative approaches)?

One suggestions was to include the external processing in the form validation, which is not ideal because the external process does a lot more than merely validate.

Answer 1

For Django 1.7+, you should use form.add_error() instead of accessing form._errors directly.

Documentation: https://docs.djangoproject.com/en/stable/ref/forms/api/#django.forms.Form.add_error