Surprising behaviour in case of exception in form widget when DEBUG=False

[Federico Capoano]

This never happened to me and I find it very strange. Maybe it's a bug or maybe it's the intended behaviour, but I find it REALLY strange.

Consider a widget which, for some reason, raises an exception:

class CoolWidget(AdminTextareaWidget):

    def render(self, name, value, attrs={}):

        WRONG()

        return super(JsonSchemaWidget, self).render(name, value, attrs)

The widget is included in an admin form like:

class PizzaForm(forms.ModelForm):

    class Meta:

        model = Pizza

        exclude = []

        widgets = {'toppings': CoolWidget}

class PizzaAdmin(ModelAdmin):

    form = TemplateForm

Now, if DEBUG is True, trying to open the relative pizza change or add form will result in:

NameError: name 'WRONG' is not defined

When DEBUG to False what I see is really strange:

I get an empty change/add form!

Now suppose that the condition that raises the exception happens only on a remote server

which has DEBUG=False. The exception happens because the configuration of a django project

has not been updated correctly yet.

Instead of failing loud, it will fail silently, leaving an empty add/change form.

Is it the intended behaviour? Or a bug?

I guess it is related due to the fact that template errors are silenced.

Federico

[Tim Graham]

Yes, I think it's {% include %} rendering an empty string if there's an exception. In Django 1.9, we added a logger for these exceptions to make debugging easier: https://docs.djangoproject.com/en/stable/topics/logging/#django-template.

[Federico Capoano]

Right, I see the log entries. Good to know there's a way to log them, for those who use sentry it will be even easier to notice this problem,

just ensure you're logging WARNING messages.

Thanks

Federico