Another common use case is to overwrite ``attrs``'s defaults.

Mypy

Unfortunately, decorator wrapping currently `confuses<https://github.com/python/mypy/issues/5406>`_ mypy's ``attrs`` plugin.

At the moment, the best workaround is to hold your nose, write a fake mypy plugin, and mutate a bunch of global variables::

You can only use this trick to tell mypy that a class is actually an ``attrs`` class.

Pyright

Generic decorator wrapping is supported in ``pyright`` viathe provisionaldataclass_transform_ specification.

Generic decorator wrapping is supported in `pyright<https://github.com/microsoft/pyright>`_ viatheirdataclass_transform_ specification.

For a custom wrapping of the form::

..note::

..warning::

``dataclass_transform`` is supported **provisionally** as of ``pyright`` 1.1.135.

``dataclass_transform``is supported provisionally as of ``pyright``1.1.135.

Both the ``pyright``dataclass_transform_ specification and ``attrs``implementation may change in future versions.

Both the ``pyright``dataclass_transform_ specification and ``attrs`` implementation may changed in future versions.

Types

.. _dataclass_transform:https://github.com/microsoft/pyright/blob/1.1.135/specs/dataclass_transforms.md

.. _dataclass_transform:https://github.com/microsoft/pyright/blob/master/specs/dataclass_transforms.md

When this happens, ``attrs`` will simply put these string literals into the ``type`` attributes.

If you need to resolve these to real types, you can call `attr.resolve_types` which will update the attribute in place.

In practice though, types show their biggest usefulness in combination with tools likemypy_,pytype_ orpyright_ that have dedicated support for ``attrs`` classes.

In practice though, types show their biggest usefulness in combination with tools likemypy_,pytype_, orpyright_ that have dedicated support for ``attrs`` classes.

The addition of static types is certainly one of the most exciting features in the Python ecosystem and helps you writing *correct* and *verified self-documenting* code.

If you don't know where to start, Carl Meyer gave a great talk on `Type-checked Python in the Real World<https://www.youtube.com/watch?v=pMgmKJyWKn8>`_ at PyCon US 2018 that will help you to get started in no time.

mypy

Given the following definition, ``pyright`` will generate static type signatures for ``SomeClass`` attribute access, ``__init__``, ``__eq__``, and comparison methods::

..note::

..warning::

``dataclass_transform``-based types are supported provisionally as of ``pyright`` 1.1.135 and ``attrs`` 21.1.

Both the ``pyright``dataclass_transform_ specification and ``attrs`` implementation may changed in future versions.

The ``pyright`` inferred types are a subset of those supported by ``mypy``, including:

- The generated ``__init__`` signature only includes the attribute type annotations,

and does not include attribute ``converter`` types.

- The generated ``__init__`` signature only includes the attribute type annotations.

It currently does not include attribute ``converter`` types.

- The ``attr.frozen`` decorator is not typed with frozen attributes, which are properly typed via ``attr.define(frozen=True)``.

Your constructive feedback is welcome in both `attrs#795<https://github.com/python-attrs/attrs/issues/795>`_ and `pyright#1782<https://github.com/microsoft/pyright/discussions/1782>`_.

.. _mypy:http://mypy-lang.org

.. _pytype:https://google.github.io/pytype/

.. _pyright:https://github.com/microsoft/pyright

.. _dataclass_transform:https://github.com/microsoft/pyright/blob/1.1.135/specs/dataclass_transforms.md

.. _dataclass_transform:https://github.com/microsoft/pyright/blob/master/specs/dataclass_transforms.md

deps = nodeenv

commands =

nodeenv --prebuilt --node=lts --force {envdir}

npm install -g --no-package-lock --no-save pyright@1.1.135

npm install -g --no-package-lock --no-save pyright

pytest tests/test_pyright.py -vv