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 fi

Answer 1

Form._errors can be treated like a standard dictionary. It's considered good form to use the ErrorList class, and to append errors to the existing list:

from django.forms.utils import ErrorList
errors = form._errors.setdefault("myfield", ErrorList())
errors.append(u"My error here")

And if you want to add non-field errors, use django.forms.forms.NON_FIELD_ERRORS (defaults to "__all__") instead of "myfield".