from django.core import checks class CheckFieldDefaultMixin: _default_hint = ('<valid default>', '<invalid default>') def _check_default(self): if self.has_default() and self.default is not None and not callable(self.default): return [ checks.Warning( "%s default should be a callable instead of an instance so " "that it's not shared between all field instances." % ( self.__class__.__name__, ), hint=( 'Use a callable instead, e.g., use `%s` instead of ' '`%s`.' % self._default_hint ), obj=self, id='postgres.E003', ) ] else: return [] def check(self, **kwargs): errors = super().check(**kwargs) errors.extend(self._check_default()) return errors