Marshmallow

+++++++++++++++++++++

Features:

- Make the error messages for "unknown fields" and "invalid data type"
configurable (:issue:`852`). Thanks :user:`Dunstrom` for the PR.
- ``fields.Boolean`` parses ``"yes"``/``"no"`` values (:pr:`1081`).
Thanks :user:`r1b`.

Other changes:

- *Backwards-incompatible with previous 3.x versions*: Change ordering
of ``keys`` and ``values`` arguments to ``fields.Dict``.
- Remove unused code in ``marshmallow.utils``: ``is_indexable_but_not_string``,
``float_to_decimal``, ``decimal_to_fixed``, ``from_iso`` (:pr:`1088`).
- Remove unused ``marshmallow.compat.string_types``.

Bug fixes:

- Includes bug fix from 2.18.0.

+++++++++++++++++++++

Features:

- Add ``register`` *class Meta* option to allow bypassing marshmallow's
internal class registry when memory usage is critical (:issue:`660`).

Bug fixes:

- Fix serializing dict-like objects with properties (:issue:`1060`).
Thanks :user:`taion` for the fix.
- Fix populating ``ValidationError.valid_data`` for ``List`` and
``Dict`` fields (:issue:`766`).

Other changes:

- Add ``marshmallow.__version_info__`` (:pr:`1074`).
- Remove the ``marshmallow.marshalling`` internal module (:pr:`1070`).
- A ``ValueError`` is raised when the ``missing`` parameter is passed
for required fields (:issue:`1040`).
- Extra keyword arguments passed to ``ValidationError`` in validators
are no longer passed to the final ``ValidationError`` raised upon
validation completion (:issue:`996`).

+++++++++++++++++++++

Features:

- *Backwards-incompatible*: Rework ``ValidationError`` API.
It now expects a single field name, and error structures are merged
in the final ``ValidationError`` raised when validation completes.
This allows schema-level validators to raise errors for individual
fields (:issue:`441`). Thanks :user:`maximkulkin` for
writing the original ``merge_errors`` implementation in :pr:`442` and thanks
:user:`lafrech` for completing the implementation in :pr:`1026`.

Bug fixes:

- Fix ``TypeError`` when serializing ``None`` with ``Pluck`` (:pr:`1049`).
Thanks :user:`toffan` for the catch and patch.

+++++++++++++++++++++

Bug fixes:

- Includes bug fixes from 2.16.2 and 2.16.3.

+++++++++++++++++++++

Features:

- Support partial loading of nested fields (:pr:`438`). Thanks
:user:`arbor-dwatson` for the PR. *Note*: Subclasses of ``fields.Nested``
now take an additional ``partial`` parameter in the ``_deserialize``
method.

Bug fixes:

- Restore ``Schema.TYPE_MAPPING``, which was removed in 3.0.0b17 (:issue:`1012`).

Other changes:

- *Backwards-incompatible*: ``_serialize`` and ``_deserialize`` methods of
all ``fields.Field`` subclasses must accept ``**kwargs`` (:pr:`1007`).

+++++++++++++++++++++

Bug fixes:

- Fix ``Date`` deserialization when using custom format (:issue:`1001`). Thanks
:user:`Ondkloss` for reporting.

Deprecations/Removals:

- ``prefix`` parameter or ``Schema`` class is removed (:issue:`991`). The same
can be achieved using a ``post_dump`` method.