Make Django templates error super loudly, maybe?

monkeypatch.py

from django.template import TemplateSyntaxError
from django.template.base import Variable, VariableDoesNotExist

old_resolve = Variable._resolve_lookup
def x(self, context):
    try:
        return old_resolve(self, context)
    except VariableDoesNotExist as e:
        part = e.params[0]
        if part not in ("SETTINGS_MODULE",):
             # I dunno. I think because I'm using a UserSettingsHolder and not
             # an actual Settings, failing to check this caused the
             # technical 500 page to fail to render ... lol.
            if part != self.var:
                msg = u"Token '{token}' of '{var}' does not resolve"
            else:
                msg = u"Variable '{token}' does not exist"
            raise TemplateSyntaxError(msg.format(token=part, var=self.var))
    # this functions the same as string_if_invalid I guess.
    # It is only hit for SETTINGS_MODULE
    return "<MISSING>"
Variable._resolve_lookup = x

Alternatively if you just wanted variables to complain loudly, and not attribute access inside nodes like {% if ... %}

class Oof(object):
    def __mod__(self, other):
        raise LookupError("Invalid value for %s" % (other,))

    def __contains__(self, item):
        return item == '%s'