History¶

1.1.1 (2020-10-30)¶

Python 2, 3.5 and 3.6 support removal. If you need it, use a version below 1.1.0.
Python 3.9 support, including support for built-in generic types (list[int] vs typing.List[int]).
cattrs now includes functions to generate specialized structuring and unstructuring hooks. Specialized hooks are faster and support overrides (omit_if_default and rename). See the cattr.gen module.
cattrs now includes a converter variant, cattr.GenConverter, that automatically generates specialized hooks for attrs classes. This converter will become the default in the future.
Generating specialized structuring hooks now invokes attr.resolve_types on a class if the class makes use of the new PEP 563 annotations.
cattrs now depends on attrs >= 20.1.0, because of attr.resolve_types.
Specialized hooks now support generic classes. The default converter will generate and use a specialized hook upon encountering a generic class.

The disambiguation function generator now supports unions of attrs classes and NoneType.

Removed the undocumented Converter.unstruct_strat property setter.
Removed the ability to set the Converter.structure_attrs instance field.

As an alternative, create a new Converter::

.. code-block:: python

>>> converter = cattr.Converter(unstruct_strat=cattr.UnstructureStrategy.AS_TUPLE)
Some micro-optimizations were applied; a structure(unstructure(obj)) roundtrip is now up to 2 times faster.

structure/unstructure now supports using functions as well as classes for deciding the appropriate function.
added Converter.register_structure_hook_func, to register a function instead of a class for determining handler func.
added Converter.register_unstructure_hook_func, to register a function instead of a class for determining handler func.
vendored typing is no longer needed, nor provided.
Attributes with default values can now be structured if they are missing in the input. (#15)
Optional attributes can no longer be structured if they are missing in the input.

In other words, this no longer works:

.. code-block:: python

@attr.s

class A:

a: Optional[int] = attr.ib()

>>> cattr.structure({}, A)
cattr.typed removed since the functionality is now present in attrs itself. Replace instances of cattr.typed(type) with attr.ib(type=type).

Converter.loads is now Converter.structure, and Converter.dumps is now Converter.unstructure.
Python 2.7 is supported.
Moved cattr.typing to cattr.vendor.typing to support different vendored versions of typing.py for Python 2 and Python 3.
Type metadata can be added to attrs classes using cattr.typed.

Python 3.4 is no longer supported.
Introduced cattr.typing for use with Python versions 3.5.2 and 3.6.0.
Minor changes to work with newer versions of typing.
- Bare Optionals are not supported any more (use Optional[Any]).
Attempting to load unrecognized classes will result in a ValueError, and a helpful message to register a loads hook.
Loading attrs classes is now documented.
The global converter is now documented.
cattr.loads_attrs_fromtuple and cattr.loads_attrs_fromdict are now exposed.