Python django.core.checks.Error() Examples

def _check_on_delete(self):
        on_delete = getattr(self.rel, 'on_delete', None)
        if on_delete == SET_NULL and not self.null:
            return [
                checks.Error(
                    'Field specifies on_delete=SET_NULL, but cannot be null.',
                    hint='Set null=True argument on the field, or change the on_delete rule.',
                    obj=self,
                    id='fields.E320',
                )
            ]
        elif on_delete == SET_DEFAULT and not self.has_default():
            return [
                checks.Error(
                    'Field specifies on_delete=SET_DEFAULT, but has no default value.',
                    hint='Set a default value, or change the on_delete rule.',
                    obj=self,
                    id='fields.E321',
                )
            ]
        else:
            return [] 

def geoip_db_is_available(app_configs, **kwargs):
    errors = []
    if geolocation.geoip_reader is None:
        # try loading it
        geolocation.load_geoip_database()
        if geolocation.geoip_reader is None:
            errors.append(Error("GeoIP DB not available", id=ERROR_GEOIP_DB_NOT_AVAILABLE))

    if not errors:
        # DB seems to be available, try and do a lookup that should resolve to
        # some country. The specific country isn't important.
        ip = "1.2.3.4"
        country = geolocation.get_country_code(ip)
        if country is None:
            errors.append(
                Error(
                    f"GeoIP DB returned no country for {ip!r}", id=ERROR_GEOIP_DB_UNEXPECTED_RESULT
                )
            )

    return errors 

def check(cls, **kwargs):
        """
        We use .session_key and CSRF_COOKIE above: check that they will be there, and fail fast if not.
        """
        errors = super().check(**kwargs)

        # Ensure we are using the database session store. (Other SessionStores may also have .session_key?)
        engine = import_module(settings.SESSION_ENGINE)
        store = engine.SessionStore
        if not issubclass(store, DatabaseSessionStore):
            errors.append(Error(
                "Quiz logging uses request.session.session_key, which likely implies "
                "SESSION_ENGINE = 'django.contrib.sessions.backends.db' in settings."
            ))

        if 'django.middleware.csrf.CsrfViewMiddleware' not in settings.MIDDLEWARE:
            errors.append(Error(
                "CsrfViewMiddleware is not enabled in settings: quiz logging uses CSRF_COOKIE and will fail without "
                "CSRF checking enabled. Also it should be enabled in general."
            ))

        return errors 

def actions_have_consistent_hashes(app_configs, **kwargs):
    errors = []
    try:
        Action = apps.get_model("recipes", "Action")
        actions = list(Action.objects.filter(implementation__isnull=False))
    except (ProgrammingError, OperationalError, ImproperlyConfigured) as e:
        errors.append(Info(f"Could not retrieve actions: {e}", id=INFO_COULD_NOT_RETRIEVE_ACTIONS))
    else:
        for action in actions:
            if action.compute_implementation_hash() != action.implementation_hash:
                msg = "Action '{action}' (id={action.id}) has a mismatched hash".format(
                    action=action
                )
                errors.append(Error(msg, id=ERROR_MISMATCHED_ACTION_HASH))

    return errors 

def _check_column_name_clashes(cls):
        # Store a list of column names which have already been used by other fields.
        used_column_names = []
        errors = []

        for f in cls._meta.local_fields:
            _, column_name = f.get_attname_column()

            # Ensure the column name is not already in use.
            if column_name and column_name in used_column_names:
                errors.append(
                    checks.Error(
                        "Field '%s' has column name '%s' that is used by "
                        "another field." % (f.name, column_name),
                        hint="Specify a 'db_column' for the field.",
                        obj=cls,
                        id='models.E007'
                    )
                )
            else:
                used_column_names.append(column_name)

        return errors 

def _check_swappable(cls):
        """Check if the swapped model exists."""
        errors = []
        if cls._meta.swapped:
            try:
                apps.get_model(cls._meta.swapped)
            except ValueError:
                errors.append(
                    checks.Error(
                        "'%s' is not of the form 'app_label.app_name'." % cls._meta.swappable,
                        id='models.E001',
                    )
                )
            except LookupError:
                app_label, model_name = cls._meta.swapped.split('.')
                errors.append(
                    checks.Error(
                        "'%s' references '%s.%s', which has not been "
                        "installed, or is abstract." % (
                            cls._meta.swappable, app_label, model_name
                        ),
                        id='models.E002',
                    )
                )
        return errors 

def _check_model_name_db_lookup_clashes(cls):
        errors = []
        model_name = cls.__name__
        if model_name.startswith('_') or model_name.endswith('_'):
            errors.append(
                checks.Error(
                    "The model name '%s' cannot start or end with an underscore "
                    "as it collides with the query lookup syntax." % model_name,
                    obj=cls,
                    id='models.E023'
                )
            )
        elif LOOKUP_SEP in model_name:
            errors.append(
                checks.Error(
                    "The model name '%s' cannot contain double underscores as "
                    "it collides with the query lookup syntax." % model_name,
                    obj=cls,
                    id='models.E024'
                )
            )
        return errors 

def _check_column_name_clashes(cls):
        # Store a list of column names which have already been used by other fields.
        used_column_names = []
        errors = []

        for f in cls._meta.local_fields:
            _, column_name = f.get_attname_column()

            # Ensure the column name is not already in use.
            if column_name and column_name in used_column_names:
                errors.append(
                    checks.Error(
                        "Field '%s' has column name '%s' that is used by "
                        "another field." % (f.name, column_name),
                        hint="Specify a 'db_column' for the field.",
                        obj=cls,
                        id='models.E007'
                    )
                )
            else:
                used_column_names.append(column_name)

        return errors 

def _check_referencing_to_swapped_model(self):
        if (self.rel.to not in apps.get_models() and
                not isinstance(self.rel.to, six.string_types) and
                self.rel.to._meta.swapped):
            model = "%s.%s" % (
                self.rel.to._meta.app_label,
                self.rel.to._meta.object_name
            )
            return [
                checks.Error(
                    ("Field defines a relation with the model '%s', "
                     "which has been swapped out.") % model,
                    hint="Update the relation to point at 'settings.%s'." % self.rel.to._meta.swappable,
                    obj=self,
                    id='fields.E301',
                )
            ]
        return [] 

def check(self, **kwargs):
        errors = super(ArrayField, self).check(**kwargs)
        if self.base_field.rel:
            errors.append(
                checks.Error(
                    'Base field for array cannot be a related field.',
                    hint=None,
                    obj=self,
                    id='postgres.E002'
                )
            )
        else:
            # Remove the field name checks as they are not needed here.
            base_errors = self.base_field.check()
            if base_errors:
                messages = '\n    '.join('%s (%s)' % (error.msg, error.id) for error in base_errors)
                errors.append(
                    checks.Error(
                        'Base field for array has errors:\n    %s' % messages,
                        hint=None,
                        obj=self,
                        id='postgres.E001'
                    )
                )
        return errors 

def check(cls, model, **kwargs):
        if cls.validator_class:
            warnings.warn(
                'ModelAdmin.validator_class is deprecated. '
                'ModelAdmin validators must be converted to use '
                'the system check framework.',
                RemovedInDjango19Warning)
            validator = cls.validator_class()
            try:
                validator.validate(cls, model)
            except ImproperlyConfigured as e:
                return [checks.Error(e.args[0], hint=None, obj=cls)]
            else:
                return []
        else:
            return cls.checks_class().check(cls, model, **kwargs) 

def _check_null_allowed_for_primary_keys(self):
        if (self.primary_key and self.null and
                not connection.features.interprets_empty_strings_as_nulls):
            # We cannot reliably check this for backends like Oracle which
            # consider NULL and '' to be equal (and thus set up
            # character-based fields a little differently).
            return [
                checks.Error(
                    'Primary keys must not have null=True.',
                    hint=('Set null=False on the field, or '
                          'remove primary_key=True argument.'),
                    obj=self,
                    id='fields.E007',
                )
            ]
        else:
            return [] 

def _check_max_length_attribute(self, **kwargs):
        try:
            max_length = int(self.max_length)
            if max_length <= 0:
                raise ValueError()
        except TypeError:
            return [
                checks.Error(
                    "CharFields must define a 'max_length' attribute.",
                    hint=None,
                    obj=self,
                    id='fields.E120',
                )
            ]
        except ValueError:
            return [
                checks.Error(
                    "'max_length' must be a positive integer.",
                    hint=None,
                    obj=self,
                    id='fields.E121',
                )
            ]
        else:
            return [] 

def _check_mutually_exclusive_options(self):
        # auto_now, auto_now_add, and default are mutually exclusive
        # options. The use of more than one of these options together
        # will trigger an Error
        mutually_exclusive_options = [self.auto_now_add, self.auto_now,
                                      self.has_default()]
        enabled_options = [option not in (None, False)
                          for option in mutually_exclusive_options].count(True)
        if enabled_options > 1:
            return [
                checks.Error(
                    "The options auto_now, auto_now_add, and default "
                    "are mutually exclusive. Only one of these options "
                    "may be present.",
                    hint=None,
                    obj=self,
                    id='fields.E160',
                )
            ]
        else:
            return [] 

def _check_decimal_places(self):
        try:
            decimal_places = int(self.decimal_places)
            if decimal_places < 0:
                raise ValueError()
        except TypeError:
            return [
                checks.Error(
                    "DecimalFields must define a 'decimal_places' attribute.",
                    hint=None,
                    obj=self,
                    id='fields.E130',
                )
            ]
        except ValueError:
            return [
                checks.Error(
                    "'decimal_places' must be a non-negative integer.",
                    hint=None,
                    obj=self,
                    id='fields.E131',
                )
            ]
        else:
            return [] 

def _check_max_digits(self):
        try:
            max_digits = int(self.max_digits)
            if max_digits <= 0:
                raise ValueError()
        except TypeError:
            return [
                checks.Error(
                    "DecimalFields must define a 'max_digits' attribute.",
                    hint=None,
                    obj=self,
                    id='fields.E132',
                )
            ]
        except ValueError:
            return [
                checks.Error(
                    "'max_digits' must be a positive integer.",
                    hint=None,
                    obj=self,
                    id='fields.E133',
                )
            ]
        else:
            return [] 

def _check_readonly_fields_item(self, cls, model, field_name, label):
        if callable(field_name):
            return []
        elif hasattr(cls, field_name):
            return []
        elif hasattr(model, field_name):
            return []
        else:
            try:
                model._meta.get_field(field_name)
            except FieldDoesNotExist:
                return [
                    checks.Error(
                        "The value of '%s' is not a callable, an attribute of '%s', or an attribute of '%s.%s'." % (
                            label, cls.__name__, model._meta.app_label, model._meta.object_name
                        ),
                        hint=None,
                        obj=cls,
                        id='admin.E035',
                    )
                ]
            else:
                return [] 

def _check_radio_fields_value(self, cls, model, val, label):
        """ Check type of a value of `radio_fields` dictionary. """

        from django.contrib.admin.options import HORIZONTAL, VERTICAL

        if val not in (HORIZONTAL, VERTICAL):
            return [
                checks.Error(
                    "The value of '%s' must be either admin.HORIZONTAL or admin.VERTICAL." % label,
                    hint=None,
                    obj=cls,
                    id='admin.E024',
                )
            ]
        else:
            return [] 

def _check_radio_fields_key(self, cls, model, field_name, label):
        """ Check that a key of `radio_fields` dictionary is name of existing
        field and that the field is a ForeignKey or has `choices` defined. """

        try:
            field = model._meta.get_field(field_name)
        except FieldDoesNotExist:
            return refer_to_missing_field(field=field_name, option=label,
                                          model=model, obj=cls, id='admin.E022')
        else:
            if not (isinstance(field, models.ForeignKey) or field.choices):
                return [
                    checks.Error(
                        "The value of '%s' refers to '%s', which is not an "
                        "instance of ForeignKey, and does not have a 'choices' definition." % (
                            label, field_name
                        ),
                        hint=None,
                        obj=cls,
                        id='admin.E023',
                    )
                ]
            else:
                return [] 

def _check_exclude(self, cls, model):
        """ Check that exclude is a sequence without duplicates. """

        if cls.exclude is None:  # default value is None
            return []
        elif not isinstance(cls.exclude, (list, tuple)):
            return must_be('a list or tuple', option='exclude', obj=cls, id='admin.E014')
        elif len(cls.exclude) > len(set(cls.exclude)):
            return [
                checks.Error(
                    "The value of 'exclude' contains duplicate field(s).",
                    hint=None,
                    obj=cls,
                    id='admin.E015',
                )
            ]
        else:
            return [] 

def _check_generic_foreign_key_existence(self):
        target = self.rel.to
        if isinstance(target, ModelBase):
            # Using `vars` is very ugly approach, but there is no better one,
            # because GenericForeignKeys are not considered as fields and,
            # therefore, are not included in `target._meta.local_fields`.
            fields = target._meta.virtual_fields
            if any(isinstance(field, GenericForeignKey) and
                    field.ct_field == self.content_type_field_name and
                    field.fk_field == self.object_id_field_name
                    for field in fields):
                return []
            else:
                return [
                    checks.Error(
                        ("The GenericRelation defines a relation with the model "
                         "'%s.%s', but that model does not have a GenericForeignKey.") % (
                            target._meta.app_label, target._meta.object_name
                        ),
                        hint=None,
                        obj=self,
                        id='contenttypes.E004',
                    )
                ]
        else:
            return [] 

def _check_exclude_of_parent_model(self, cls, parent_model):
        # Do not perform more specific checks if the base checks result in an
        # error.
        errors = super(InlineModelAdminChecks, self)._check_exclude(cls, parent_model)
        if errors:
            return []

        # Skip if `fk_name` is invalid.
        if self._check_relation(cls, parent_model):
            return []

        if cls.exclude is None:
            return []

        fk = _get_foreign_key(parent_model, cls.model, fk_name=cls.fk_name)
        if fk.name in cls.exclude:
            return [
                checks.Error(
                    "Cannot exclude the field '%s', because it is the foreign key "
                    "to the parent model '%s.%s'." % (
                        fk.name, parent_model._meta.app_label, parent_model._meta.object_name
                    ),
                    hint=None,
                    obj=cls,
                    id='admin.E201',
                )
            ]
        else:
            return [] 

def _check_model(cls):
        errors = []
        if cls._meta.proxy:
            if cls._meta.local_fields or cls._meta.local_many_to_many:
                errors.append(
                    checks.Error(
                        "Proxy model '%s' contains model fields." % cls.__name__,
                        id='models.E017',
                    )
                )
        return errors 

def _check_m2m_through_same_relationship(cls):
        """ Check if no relationship model is used by more than one m2m field.
        """

        errors = []
        seen_intermediary_signatures = []

        fields = cls._meta.local_many_to_many

        # Skip when the target model wasn't found.
        fields = (f for f in fields if isinstance(f.remote_field.model, ModelBase))

        # Skip when the relationship model wasn't found.
        fields = (f for f in fields if isinstance(f.remote_field.through, ModelBase))

        for f in fields:
            signature = (f.remote_field.model, cls, f.remote_field.through)
            if signature in seen_intermediary_signatures:
                errors.append(
                    checks.Error(
                        "The model has two many-to-many relations through "
                        "the intermediate model '%s'." % f.remote_field.through._meta.label,
                        obj=cls,
                        id='models.E003',
                    )
                )
            else:
                seen_intermediary_signatures.append(signature)
        return errors 

def _check_inlines_item(self, cls, model, inline, label):
        """ Check one inline model admin. """
        inline_label = '.'.join([inline.__module__, inline.__name__])

        from django.contrib.admin.options import BaseModelAdmin

        if not issubclass(inline, BaseModelAdmin):
            return [
                checks.Error(
                    "'%s' must inherit from 'BaseModelAdmin'." % inline_label,
                    hint=None,
                    obj=cls,
                    id='admin.E104',
                )
            ]
        elif not inline.model:
            return [
                checks.Error(
                    "'%s' must have a 'model' attribute." % inline_label,
                    hint=None,
                    obj=cls,
                    id='admin.E105',
                )
            ]
        elif not issubclass(inline.model, models.Model):
            return must_be('a Model', option='%s.model' % inline_label,
                           obj=cls, id='admin.E106')
        else:
            return inline.check(model) 

def _check_id_field(cls):
        """Check if `id` field is a primary key."""
        fields = [f for f in cls._meta.local_fields if f.name == 'id' and f != cls._meta.pk]
        # fields is empty or consists of the invalid "id" field
        if fields and not fields[0].primary_key and cls._meta.pk.name == 'id':
            return [
                checks.Error(
                    "'id' can only be used as a field name if the field also "
                    "sets 'primary_key=True'.",
                    obj=cls,
                    id='models.E004',
                )
            ]
        else:
            return [] 

def _check_ordering_item(self, cls, model, field_name, label):
        """ Check that `ordering` refers to existing fields. """

        if field_name == '?' and len(cls.ordering) != 1:
            return [
                checks.Error(
                    ("The value of 'ordering' has the random ordering marker '?', "
                     "but contains other fields as well."),
                    hint='Either remove the "?", or remove the other fields.',
                    obj=cls,
                    id='admin.E032',
                )
            ]
        elif field_name == '?':
            return []
        elif '__' in field_name:
            # Skip ordering in the format field1__field2 (FIXME: checking
            # this format would be nice, but it's a little fiddly).
            return []
        else:
            if field_name.startswith('-'):
                field_name = field_name[1:]

            try:
                model._meta.get_field(field_name)
            except FieldDoesNotExist:
                return refer_to_missing_field(field=field_name, option=label,
                                              model=model, obj=cls, id='admin.E033')
            else:
                return [] 

def _check_prepopulated_fields_key(self, cls, model, field_name, label):
        """ Check a key of `prepopulated_fields` dictionary, i.e. check that it
        is a name of existing field and the field is one of the allowed types.
        """

        forbidden_field_types = (
            models.DateTimeField,
            models.ForeignKey,
            models.ManyToManyField
        )

        try:
            field = model._meta.get_field(field_name)
        except FieldDoesNotExist:
            return refer_to_missing_field(field=field_name, option=label,
                                          model=model, obj=cls, id='admin.E027')
        else:
            if isinstance(field, forbidden_field_types):
                return [
                    checks.Error(
                        "The value of '%s' refers to '%s', which must not be a DateTimeField, "
                        "ForeignKey or ManyToManyField." % (
                            label, field_name
                        ),
                        hint=None,
                        obj=cls,
                        id='admin.E028',
                    )
                ]
            else:
                return [] 

def _check_latitude_field(self):
        opts = self.model._meta
        try:
            opts.get_field(self.latitude_field_name)
        except FieldDoesNotExist:
            return [
                checks.Error(
                    "The OSMField '%s' references the non-existent latitude field '%s'."
                    % (self.name, self.latitude_field_name,),
                    hint=None,
                    obj=self,
                    id="osm_field.E001",
                )
            ]
        else:
            return [] 

def _check_fieldsets_item(self, cls, model, fieldset, label):
        """ Check an item of `fieldsets`, i.e. check that this is a pair of a
        set name and a dictionary containing "fields" key. """

        if not isinstance(fieldset, (list, tuple)):
            return must_be('a list or tuple', option=label, obj=cls, id='admin.E008')
        elif len(fieldset) != 2:
            return must_be('of length 2', option=label, obj=cls, id='admin.E009')
        elif not isinstance(fieldset[1], dict):
            return must_be('a dictionary', option='%s[1]' % label, obj=cls, id='admin.E010')
        elif 'fields' not in fieldset[1]:
            return [
                checks.Error(
                    "The value of '%s[1]' must contain the key 'fields'." % label,
                    hint=None,
                    obj=cls,
                    id='admin.E011',
                )
            ]
        elif not isinstance(fieldset[1]['fields'], (list, tuple)):
            return must_be('a list or tuple', option="%s[1]['fields']" % label, obj=cls, id='admin.E008')

        fields = flatten(fieldset[1]['fields'])
        if len(fields) != len(set(fields)):
            return [
                checks.Error(
                    "There are duplicate field(s) in '%s[1]'." % label,
                    hint=None,
                    obj=cls,
                    id='admin.E012',
                )
            ]
        return list(chain(*[
            self._check_field_spec(cls, model, fieldset_fields, '%s[1]["fields"]' % label)
            for fieldset_fields in fieldset[1]['fields']
        ]))