Marshmallow

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

Bug fixes:

- Errors reported by a schema-level validator for a field in a ``Nested`` field
are stored under corresponding field name, not ``_schema`` key (:pr:`862`).
- Includes bug fix from 2.15.4.

Other changes:

- *Backwards-incompatible*: The ``unknown`` option now defaults to ``RAISE``
(`524 (comment) <https://github.com/marshmallow-code/marshmallow/issues/524#issuecomment-397165731>`_,
:issue:`851`).
- *Backwards-incompatible*: When a schema error is raised with a ``dict`` as
payload, the ``dict`` overwrites any existing error list. Before this change,
it would be appended to the list.
- Raise a `StringNotCollectionError` if ``only`` or ``exclude`` is
passed as a string (:issue:`316`). Thanks :user:`paulocheque` for
reporting.

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

Features:

- The behavior to apply when encountering unknown fields while deserializing
can be controlled with the ``unknown`` option (:issue:`524`,
:issue:`747`, :issue:`127`).
It makes it possible to either "include", "exclude", or "raise".
Thanks :user:`tuukkamustonen` for the suggestion and thanks
:user:`ramnes` for the PR.

.. warning::

The default for ``unknown`` will be changed to ``RAISE`` in the
next release.

Other changes:

- *Backwards-incompatible*: Pre/Post-processors MUST return modified data.
Returning ``None`` does not imply data were mutated (:issue:`347`). Thanks
:user:`tdevelioglu` for reporting.
- *Backwards-incompatible*: ``only`` and ``exclude`` are bound by
declared and additional fields. A ``ValueError`` is raised if invalid
fields are passed (:issue:`636`). Thanks :user:`jan-23` for reporting.
Thanks :user:`ikilledthecat` and :user:`deckar01` for the PRs.
- Format code using pre-commit (:pr:`855`).

Deprecations/Removals:

- ``ValidationError.fields`` is removed (:issue:`840`). Access field
instances from ``Schema.fields``.

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

Features:

- Clean up code for schema hooks (:pr:`814`). Thanks :user:`taion`.
- Minor performance improvement from simplifying ``utils.get_value`` (:pr:`811`). Thanks again :user:`taion`.
- Add ``require_tld`` argument to ``fields.URL`` (:issue:`749`). Thanks
:user:`DenerKup` for reporting and thanks :user:`surik00` for the PR.
- ``fields.UUID`` deserializes ``bytes`` strings using ``UUID(bytes=b'...')`` (:pr:`625`).
Thanks :user:`JeffBerger` for the suggestion and the PR.

Bug fixes:

- Fields nested within ``Dict`` correctly inherit context from their
parent schema (:issue:`820`). Thanks :user:`RosanneZe` for reporting
and :user:`deckar01` for the PR.
- Includes bug fix from 2.15.3.

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

Bug fixes:

- Includes bugfixes from 2.15.2.

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

Features:

- *Backwards-incompatible*: ``missing`` and ``default`` values are
passed in deserialized form (:issue:`378`). Thanks :user:`chadrik` for
the suggestion and thanks :user:`lafrech` for the PR.

Bug fixes:

- Includes the bugfix from 2.15.1.

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

Features:

- *Backwards-incompatible*: Add ``data_key`` parameter to fields for
specifying the key in the input and output data dict. This
parameter replaces both ``load_from`` and ``dump_to`` (:issue:`717`).
Thanks :user:`lafrech`.
- *Backwards-incompatible*: When ``pass_original=True`` is passed to one
of the decorators and a collection is being (de)serialized, the
``original_data`` argument will be a single object unless
``pass_many=True`` is also passed to the decorator (:issue:`315`,
:issue:`743`). Thanks :user:`stj` for the PR.
- *Backwards-incompatible*: Don't recursively check nested required
fields when the ``Nested`` field's key is missing (:issue:`319`). This
reverts :pr:`235`. Thanks :user:`chekunkov` reporting and thanks
:user:`lafrech` for the PR.
- *Backwards-incompatible*: Change error message collection for ``Dict`` field (:issue:`730`). Note:
this is backwards-incompatible with previous 3.0.0bX versions.
Thanks :user:`shabble` for the report and thanks :user:`lafrech` for the PR.