====================== System check framework ====================== .. currentmodule:: django.core.checks The system check framework is a set of static checks for validating Django projects. It detects common problems and provides hints for how to fix them. The framework is extensible so you can easily add your own checks. For details on how to add your own checks and integrate them with Django's system checks, see the :doc:`System check topic guide `. API Reference ============= ``CheckMessage`` ----------------- .. class:: CheckMessage(level, msg, hint=None, obj=None, id=None) The warnings and errors raised by system checks must be instances of ``CheckMessage``. An instance encapsulates a single reportable error or warning. It also provides context and hints applicable to the message, and a unique identifier that is used for filtering purposes. Constructor arguments are: ``level`` The severity of the message. Use one of the predefined values: ``DEBUG``, ``INFO``, ``WARNING``, ``ERROR``, ``CRITICAL``. If the level is greater or equal to ``ERROR``, then Django will prevent management commands from executing. Messages with level lower than ``ERROR`` (i.e. warnings) are reported to the console, but can be silenced. ``msg`` A short (less than 80 characters) string describing the problem. The string should *not* contain newlines. ``hint`` A single-line string providing a hint for fixing the problem. If no hint can be provided, or the hint is self-evident from the error message, the hint can be omitted, or a value of ``None`` can be used. ``obj`` Optional. An object providing context for the message (for example, the model where the problem was discovered). The object should be a model, field, or manager or any other object that defines ``__str__`` method (on Python 2 you need to define ``__unicode__`` method). The method is used while reporting all messages and its result precedes the message. ``id`` Optional string. A unique identifier for the issue. Identifiers should follow the pattern ``applabel.X001``, where ``X`` is one of the letters ``CEWID``, indicating the message severity (``C`` for criticals, ``E`` for errors and so). The number can be allocated by the application, but should be unique within that application. There are subclasses to make creating messages with common levels easier. When using them you can omit the ``level`` argument because it is implied by the class name. .. class:: Debug(msg, hint=None, obj=None, id=None) .. class:: Info(msg, hint=None, obj=None, id=None) .. class:: Warning(msg, hint=None obj=None, id=None) .. class:: Error(msg, hint=None, obj=None, id=None) .. class:: Critical(msg, hint=None, obj=None, id=None) Builtin checks ============== .. _system-check-builtin-tags: Builtin tags ------------ Django's system checks are organized using the following tags: * ``models``: Checks governing model, field and manager definitions. * ``signals``: Checks on signal declarations and handler registrations. * ``admin``: Checks of any admin site declarations. * ``compatibility``: Flagging potential problems with version upgrades. * ``security``: Checks security related configuration. * ``templates``: Checks template related configuration. * ``caches``: Checks cache related configuration. * ``urls``: Checks URL configuration. Some checks may be registered with multiple tags. Core system checks ------------------ Models ~~~~~~ * **models.E001**: ```` is not of the form ``app_label.app_name``. * **models.E002**: ```` references ````, which has not been installed, or is abstract. * **models.E003**: The model has two many-to-many relations through the intermediate model ``.``. * **models.E004**: ``id`` can only be used as a field name if the field also sets ``primary_key=True``. * **models.E005**: The field ```` from parent model ```` clashes with the field ```` from parent model ````. * **models.E006**: The field clashes with the field ```` from model ````. * **models.E007**: Field ```` has column name ```` that is used by another field. * **models.E008**: ``index_together`` must be a list or tuple. * **models.E009**: All ``index_together`` elements must be lists or tuples. * **models.E010**: ``unique_together`` must be a list or tuple. * **models.E011**: All ``unique_together`` elements must be lists or tuples. * **models.E012**: ``index_together/unique_together`` refers to the non-existent field ````. * **models.E013**: ``index_together/unique_together`` refers to a ``ManyToManyField`` ````, but ``ManyToManyField``\s are not supported for that option. * **models.E014**: ``ordering`` must be a tuple or list (even if you want to order by only one field). * **models.E015**: ``ordering`` refers to the non-existent field ````. * **models.E016**: ``index_together/unique_together`` refers to field ```` which is not local to model ````. * **models.E017**: Proxy model ```` contains model fields. * **models.E018**: Autogenerated column name too long for field ````. Maximum length is ```` for database ````. * **models.E019**: Autogenerated column name too long for M2M field ````. Maximum length is ```` for database ````. * **models.E020**: The ``.check()`` class method is currently overridden. * **models.E021**: ``ordering`` and ``order_with_respect_to`` cannot be used together. Fields ~~~~~~ * **fields.E001**: Field names must not end with an underscore. * **fields.E002**: Field names must not contain ``"__"``. * **fields.E003**: ``pk`` is a reserved word that cannot be used as a field name. * **fields.E004**: ``choices`` must be an iterable (e.g., a list or tuple). * **fields.E005**: ``choices`` must be an iterable returning ``(actual value, human readable name)`` tuples. * **fields.E006**: ``db_index`` must be ``None``, ``True`` or ``False``. * **fields.E007**: Primary keys must not have ``null=True``. * **fields.E100**: ``AutoField``\s must set primary_key=True. * **fields.E110**: ``BooleanField``\s do not accept null values. * **fields.E120**: ``CharField``\s must define a ``max_length`` attribute. * **fields.E121**: ``max_length`` must be a positive integer. * **fields.W122**: ``max_length`` is ignored when used with ``IntegerField``. * **fields.E130**: ``DecimalField``\s must define a ``decimal_places`` attribute. * **fields.E131**: ``decimal_places`` must be a non-negative integer. * **fields.E132**: ``DecimalField``\s must define a ``max_digits`` attribute. * **fields.E133**: ``max_digits`` must be a non-negative integer. * **fields.E134**: ``max_digits`` must be greater or equal to ``decimal_places``. * **fields.E140**: ``FilePathField``\s must have either ``allow_files`` or ``allow_folders`` set to True. * **fields.E150**: ``GenericIPAddressField``\s cannot accept blank values if null values are not allowed, as blank values are stored as nulls. * **fields.E160**: The options ``auto_now``, ``auto_now_add``, and ``default`` are mutually exclusive. Only one of these options may be present. * **fields.W161**: Fixed default value provided. * **fields.E900**: ``IPAddressField`` has been removed except for support in historical migrations. * **fields.W900**: ``IPAddressField`` has been deprecated. Support for it (except in historical migrations) will be removed in Django 1.9. *This check appeared in Django 1.7 and 1.8*. * **fields.W901**: ``CommaSeparatedIntegerField`` has been deprecated. Support for it (except in historical migrations) will be removed in Django 2.0. File Fields ~~~~~~~~~~~ * **fields.E200**: ``unique`` is not a valid argument for a ``FileField``. * **fields.E201**: ``primary_key`` is not a valid argument for a ``FileField``. * **fields.E210**: Cannot use ``ImageField`` because Pillow is not installed. Related Fields ~~~~~~~~~~~~~~ * **fields.E300**: Field defines a relation with model ````, which is either not installed, or is abstract. * **fields.E301**: Field defines a relation with the model ```` which has been swapped out. * **fields.E302**: Accessor for field ```` clashes with field ````. * **fields.E303**: Reverse query name for field ```` clashes with field ````. * **fields.E304**: Field name ```` clashes with accessor for ````. * **fields.E305**: Field name ```` clashes with reverse query name for ````. * **fields.E306**: Related name must be a valid Python identifier or end with a ``'+'``. * **fields.E310**: No subset of the fields ````, ````, ... on model ```` is unique. Add ``unique=True`` on any of those fields or add at least a subset of them to a unique_together constraint. * **fields.E311**: ```` must set ``unique=True`` because it is referenced by a ``ForeignKey``. * **fields.E320**: Field specifies ``on_delete=SET_NULL``, but cannot be null. * **fields.E321**: The field specifies ``on_delete=SET_DEFAULT``, but has no default value. * **fields.E330**: ``ManyToManyField``\s cannot be unique. * **fields.E331**: Field specifies a many-to-many relation through model ````, which has not been installed. * **fields.E332**: Many-to-many fields with intermediate tables must not be symmetrical. * **fields.E333**: The model is used as an intermediate model by ````, but it has more than two foreign keys to ````, which is ambiguous. You must specify which two foreign keys Django should use via the ``through_fields`` keyword argument. * **fields.E334**: The model is used as an intermediate model by ````, but it has more than one foreign key from ````, which is ambiguous. You must specify which foreign key Django should use via the ``through_fields`` keyword argument. * **fields.E335**: The model is used as an intermediate model by ````, but it has more than one foreign key to ````, which is ambiguous. You must specify which foreign key Django should use via the ``through_fields`` keyword argument. * **fields.E336**: The model is used as an intermediary model by ````, but it does not have foreign key to ```` or ````. * **fields.E337**: Field specifies ``through_fields`` but does not provide the names of the two link fields that should be used for the relation through ````. * **fields.E338**: The intermediary model ```` has no field ````. * **fields.E339**: ``.`` is not a foreign key to ````. * **fields.W340**: ``null`` has no effect on ``ManyToManyField``. * **fields.W341**: ``ManyToManyField`` does not support ``validators``. * **fields.W342**: Setting ``unique=True`` on a ``ForeignKey`` has the same effect as using a ``OneToOneField``. Signals ~~~~~~~ * **signals.E001**: ```` was connected to the ```` signal with a lazy reference to the ```` sender, which has not been installed. Backwards Compatibility ~~~~~~~~~~~~~~~~~~~~~~~ The following checks are performed to warn the user of any potential problems that might occur as a result of a version upgrade. * **1_6.W001**: Some project unit tests may not execute as expected. *This check was removed in Django 1.8 due to false positives*. * **1_6.W002**: ``BooleanField`` does not have a default value. *This check was removed in Django 1.8 due to false positives*. * **1_7.W001**: Django 1.7 changed the global defaults for the ``MIDDLEWARE_CLASSES.`` ``django.contrib.sessions.middleware.SessionMiddleware``, ``django.contrib.auth.middleware.AuthenticationMiddleware``, and ``django.contrib.messages.middleware.MessageMiddleware`` were removed from the defaults. If your project needs these middleware then you should configure this setting. *This check was removed in Django 1.9*. * **1_8.W001**: The standalone ``TEMPLATE_*`` settings were deprecated in Django 1.8 and the :setting:`TEMPLATES` dictionary takes precedence. You must put the values of the following settings into your defaults ``TEMPLATES`` dict: ``TEMPLATE_DIRS``, ``TEMPLATE_CONTEXT_PROCESSORS``, ``TEMPLATE_DEBUG``, ``TEMPLATE_LOADERS``, ``TEMPLATE_STRING_IF_INVALID``. Admin ----- Admin checks are all performed as part of the ``admin`` tag. The following checks are performed on any :class:`~django.contrib.admin.ModelAdmin` (or subclass) that is registered with the admin site: * **admin.E001**: The value of ``raw_id_fields`` must be a list or tuple. * **admin.E002**: The value of ``raw_id_fields[n]`` refers to ````, which is not an attribute of ````. * **admin.E003**: The value of ``raw_id_fields[n]`` must be a foreign key or a many-to-many field. * **admin.E004**: The value of ``fields`` must be a list or tuple. * **admin.E005**: Both ``fieldsets`` and ``fields`` are specified. * **admin.E006**: The value of ``fields`` contains duplicate field(s). * **admin.E007**: The value of ``fieldsets`` must be a list or tuple. * **admin.E008**: The value of ``fieldsets[n]`` must be a list or tuple. * **admin.E009**: The value of ``fieldsets[n]`` must be of length 2. * **admin.E010**: The value of ``fieldsets[n][1]`` must be a dictionary. * **admin.E011**: The value of ``fieldsets[n][1]`` must contain the key ``fields``. * **admin.E012**: There are duplicate field(s) in ``fieldsets[n][1]``. * **admin.E013**: ``fields[n]/fieldsets[n][m]`` cannot include the many-to-many field ````, because that field manually specifies a relationship model. * **admin.E014**: The value of ``exclude`` must be a list or tuple. * **admin.E015**: The value of ``exclude`` contains duplicate field(s). * **admin.E016**: The value of ``form`` must inherit from ``BaseModelForm``. * **admin.E017**: The value of ``filter_vertical`` must be a list or tuple. * **admin.E018**: The value of ``filter_horizontal`` must be a list or tuple. * **admin.E019**: The value of ``filter_vertical[n]/filter_vertical[n]`` refers to ````, which is not an attribute of ````. * **admin.E020**: The value of ``filter_vertical[n]/filter_vertical[n]`` must be a many-to-many field. * **admin.E021**: The value of ``radio_fields`` must be a dictionary. * **admin.E022**: The value of ``radio_fields`` refers to ````, which is not an attribute of ````. * **admin.E023**: The value of ``radio_fields`` refers to ````, which is not a ``ForeignKey``, and does not have a ``choices`` definition. * **admin.E024**: The value of ``radio_fields[]`` must be either ``admin.HORIZONTAL`` or ``admin.VERTICAL``. * **admin.E025**: The value of ``view_on_site`` must be either a callable or a boolean value. * **admin.E026**: The value of ``prepopulated_fields`` must be a dictionary. * **admin.E027**: The value of ``prepopulated_fields`` refers to ````, which is not an attribute of ````. * **admin.E028**: The value of ``prepopulated_fields`` refers to ````, which must not be a ``DateTimeField``, a foreign key or a many-to-many field. * **admin.E029**: The value of ``prepopulated_fields[]`` must be a list or tuple. * **admin.E030**: The value of ``prepopulated_fields`` refers to ````, which is not an attribute of ````. * **admin.E031**: The value of ``ordering`` must be a list or tuple. * **admin.E032**: The value of ``ordering`` has the random ordering marker ``?``, but contains other fields as well. * **admin.E033**: The value of ``ordering`` refers to ````, which is not an attribute of ````. * **admin.E034**: The value of ``readonly_fields`` must be a list or tuple. * **admin.E035**: The value of ``readonly_fields[n]`` is not a callable, an attribute of ````, or an attribute of ````. ``ModelAdmin`` ~~~~~~~~~~~~~~ The following checks are performed on any :class:`~django.contrib.admin.ModelAdmin` that is registered with the admin site: * **admin.E101**: The value of ``save_as`` must be a boolean. * **admin.E102**: The value of ``save_on_top`` must be a boolean. * **admin.E103**: The value of ``inlines`` must be a list or tuple. * **admin.E104**: ```` must inherit from ``BaseModelAdmin``. * **admin.E105**: ```` must have a ``model`` attribute. * **admin.E106**: The value of ``.model`` must be a ``Model``. * **admin.E107**: The value of ``list_display`` must be a list or tuple. * **admin.E108**: The value of ``list_display[n]`` refers to ``