# pep484 stubs for Django [](https://github.com/typeddjango/django-stubs/actions?query=workflow%3Atest) [](http://mypy-lang.org/) [](https://gitter.im/mypy-django/Lobby) [](https://stackoverflow.com/questions/tagged/django-stubs) This package contains [type stubs](https://www.python.org/dev/peps/pep-0561/) and a custom mypy plugin to provide more precise static types and type inference for Django framework. Django uses some Python "magic" that makes having precise types for some code patterns problematic. This is why we need this project. The final goal is to be able to get precise types for most common patterns. ## Installation ```bash pip install django-stubs[compatible-mypy] ``` To make mypy aware of the plugin, you need to add ```ini [mypy] plugins = mypy_django_plugin.main [mypy.plugins.django-stubs] django_settings_module = "myproject.settings" ``` in your `mypy.ini` or `setup.cfg` [file](https://mypy.readthedocs.io/en/latest/config_file.html). [pyproject.toml](https://mypy.readthedocs.io/en/stable/config_file.html#using-a-pyproject-toml-file) configurations are also supported: ```toml [tool.mypy] plugins = ["mypy_django_plugin.main"] [tool.django-stubs] django_settings_module = "myproject.settings" ``` Two things happening here: 1. We need to explicitly list our plugin to be loaded by `mypy` 2. Our plugin also requires `django` settings module (what you put into `DJANGO_SETTINGS_MODULE` variable) to be specified This fully working [typed boilerplate](https://github.com/wemake-services/wemake-django-template) can serve you as an example. ## Version compatibility We rely on different `django` and `mypy` versions: | django-stubs | mypy version | django version | python version |--------------| ---- | ---- | ---- | | 1.12.0 | 0.931+ | 3.2.x or 4.0.x | ^3.7 | 1.11.0 | 0.931+ | 3.2.x | ^3.7 | 1.10.0 | 0.931+ | 3.2.x | ^3.7 | 1.9.0 | 0.910 | 3.2.x | ^3.6 | 1.8.0 | 0.812 | 3.1.x | ^3.6 | 1.7.0 | 0.790 | 2.2.x \|\| 3.x | ^3.6 | 1.6.0 | 0.780 | 2.2.x \|\| 3.x | ^3.6 | 1.5.0 | 0.770 | 2.2.x \|\| 3.x | ^3.6 | 1.4.0 | 0.760 | 2.2.x \|\| 3.x | ^3.6 | 1.3.0 | 0.750 | 2.2.x \|\| 3.x | ^3.6 | 1.2.0 | 0.730 | 2.2.x | ^3.6 | 1.1.0 | 0.720 | 2.2.x | ^3.6 | 0.12.x | old semantic analyzer (<0.711), dmypy support | 2.1.x | ^3.6 ## FAQ ### Is this an official Django project? No, it is not. We are independent from Django at the moment. There's a [proposal](https://github.com/django/deps/pull/65) to merge our project into the Django itself. You can show your support by liking the PR. ### Is it safe to use this in production? Yes, it is! This project does not affect your runtime at all. It only affects `mypy` type checking process. But, it does not make any sense to use this project without `mypy`. ### mypy crashes when I run it with this plugin installed The current implementation uses Django's runtime to extract information about models, so it might crash if your installed apps or `models.py` are broken. In other words, if your `manage.py runserver` crashes, mypy will crash too. You can also run `mypy` with [`--tb`](https://mypy.readthedocs.io/en/stable/command_line.html#cmdoption-mypy-show-traceback) option to get extra information about the error. ### I cannot use QuerySet or Manager with type annotations You can get a `TypeError: 'type' object is not subscriptable` when you will try to use `QuerySet[MyModel]`, `Manager[MyModel]` or some other Django-based Generic types. This happens because these Django classes do not support [`__class_getitem__`](https://www.python.org/dev/peps/pep-0560/#class-getitem) magic method in runtime. 1. You can go with our [`django_stubs_ext`](https://github.com/typeddjango/django-stubs/tree/master/django_stubs_ext) helper, that patches all the types we use as Generic in django. Install it: ```bash pip install django-stubs-ext # as a production dependency ``` And then place in your top-level settings: ```python import django_stubs_ext django_stubs_ext.monkeypatch() ``` Note: This monkey patching approach will only work when using Python 3.7 and higher, when the `__class_getitem__` magic method was introduced. 2. You can use strings instead: `'QuerySet[MyModel]'` and `'Manager[MyModel]'`, this way it will work as a type for `mypy` and as a regular `str` in runtime. ### How can I create a HttpRequest that's guaranteed to have an authenticated user? Django's built in `HttpRequest` has the attribute `user` that resolves to the type ```python Union[User, AnonymousUser] ``` where `User` is the user model specified by the `AUTH_USER_MODEL` setting. If you want a `HttpRequest` that you can type-annotate with where you know that the user is authenticated you can subclass the normal `HttpRequest` class like so: ```python from django.http import HttpRequest from my_user_app.models import MyUser class AuthenticatedHttpRequest(HttpRequest): user: MyUser ``` And then use `AuthenticatedHttpRequest` instead of the standard `HttpRequest` for when you know that the user is authenticated. For example in views using the `@login_required` decorator. ### My QuerySet methods are returning Any rather than my Model `QuerySet.as_manager()` is not currently supported. If you are using `MyQuerySet.as_manager()`, then your `Manager`/`QuerySet` methods will all not be linked to your model. Example: ```python from django.db import models class MyModelQuerySet(models.QuerySet): pass class MyModel(models.Model): bar = models.IntegerField() objects = MyModelQuerySet.as_manager() def use_my_model(): foo = MyModel.objects.get(id=1) # This is `Any` but it should be `MyModel` return foo.xyz # No error, but there should be ``` There is a workaround: use `Manager.from_queryset` instead. Example: ```python from django.db import models class MyModelQuerySet(models.QuerySet): pass MyModelManager = models.Manager.from_queryset(MyModelQuerySet) class MyModel(models.Model): bar = models.IntegerField() objects = MyModelManager() def use_my_model(): foo = MyModel.objects.get(id=1) return foo.xyz # Gives an error ``` ### How do I annotate cases where I called QuerySet.annotate? Django-stubs provides a special type, `django_stubs_ext.WithAnnotations[Model]`, which indicates that the `Model` has been annotated, meaning it allows getting/setting extra attributes on the model instance. Optionally, you can provide a `TypedDict` of these attributes, e.g. `WithAnnotations[MyModel, MyTypedDict]`, to specify which annotated attributes are present. Currently, the mypy plugin can recognize that specific names were passed to `QuerySet.annotate` and include them in the type, but does not record the types of these attributes. The knowledge of the specific annotated fields is not yet used in creating more specific types for `QuerySet`'s `values`, `values_list`, or `filter` methods, however knowledge that the model was annotated _is_ used to create a broader type result type for `values`/`values_list`, and to allow `filter`ing on any field. ```python from typing import TypedDict from django_stubs_ext import WithAnnotations from django.db import models from django.db.models.expressions import Value class MyModel(models.Model): username = models.CharField(max_length=100) def func(m: WithAnnotations[MyModel]) -> str: return m.asdf # OK, since the model is annotated as allowing any attribute func(MyModel.objects.annotate(foo=Value("")).get(id=1)) # OK func(MyModel.objects.get(id=1)) # Error, since this model will not allow access to any attribute class MyTypedDict(TypedDict): foo: str def func2(m: WithAnnotations[MyModel, MyTypedDict]) -> str: print(m.bar) # Error, since field "bar" is not in MyModel or MyTypedDict. return m.foo # OK, since we said field "foo" was allowed func(MyModel.objects.annotate(foo=Value("")).get(id=1)) # OK func(MyModel.objects.annotate(bar=Value("")).get(id=1)) # Error ``` ## Related projects - [`awesome-python-typing`](https://github.com/typeddjango/awesome-python-typing) - Awesome list of all typing-related things in Python. - [`djangorestframework-stubs`](https://github.com/typeddjango/djangorestframework-stubs) - Stubs for Django REST Framework. - [`pytest-mypy-plugins`](https://github.com/typeddjango/pytest-mypy-plugins) - `pytest` plugin that we use for testing `mypy` stubs and plugins. - [`wemake-django-template`](https://github.com/wemake-services/wemake-django-template) - Create new typed Django projects in seconds. ## To get help We have Gitter here: If you think you have more generic typing issue, please refer to and their Gitter. ## Contributing This project is open source and community driven. As such we encourage contributions big and small. You can contribute by doing any of the following: 1. Contribute code (e.g. improve stubs, add plugin capabilities, write tests etc) - to do so please follow the [contribution guide](./CONTRIBUTING.md). 2. Assist in code reviews and discussions in issues. 3. Identify bugs and issues and report these 4. Ask and answer questions on [StackOverflow](https://stackoverflow.com/questions/tagged/django-stubs) You can always also reach out in gitter to discuss your contributions!