id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
10968	Appears like there's something missing when subclassing django.forms' ErrorList	matehat	Luke Plant	"Django's forms feature a way to customize how errors are displayed by allowing one to subclass django.forms.util.ErrorList. However, there seems to be something missing in there to make it work completely. Let me summarize what I found :

1. When django.forms.Form gathers cleaned data in `full_clean()`, it sets keyed data on its internal `_errors` variable like so :
{{{
#!python
    except ValidationError, e:
        self._errors[name] = e.messages
}}}

2. That `e.messages` data comes from `ValidationError` Exception subclass :
{{{
#!python
    class ValidationError(Exception):
        def __init__(self, message):
            """"""
            ValidationError can be passed any object that can be printed (usually
            a string) or a list of objects.
            """"""
            if isinstance(message, list):
                self.messages = ErrorList([smart_unicode(msg) for msg in message])
            else:
                message = smart_unicode(message)
                self.messages = ErrorList([message])
}}}

3. When calling `as_ul()`, `as_p()`, etc. Form does the following :
{{{
#!python
     bf_errors = self.error_class([conditional_escape(error) for error in bf.errors]) # Escape and cache in local variable.
}}}
There, it does the right thing, i.e. wrap errors in the specified `ErrorList` subclass provided by the user, here available through `self.error_class`. As you can see though, this is not done in the ValidationError class. It just takes for granted that in should be wrapped in the original `ErrorList` class. Perfectly understandable since it doesn't know anything about the Form instance, nor any of its attribute. A very simple fix to this is to replace the line in (1):
{{{
#!python
    #       self._errors[name] = e.messages   (before)
             self._errors[name] = self.error_class(e.messages)
}}}
So I just attached a patch doing just that and adding some tests to make sure such customization works perfectly.
"		closed	Forms	1.0		fixed		mathieu@…	Unreviewed	1	0	0	0	0	0