Marshmallow

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

Features:

- ``List`` field respects the ``attribute`` argument of the inner field. Thanks :user:`jmcarp`.
- The ``container`` field ``List`` field has access to its parent ``Schema`` via its ``parent`` attribute. Thanks again :user:`jmcarp`.

Deprecation/Removals:

- Legacy validator functions have been removed (:issue:`73`). Use the class-based validators in ``marshmallow.validate`` instead.

Bug fixes:

- ``fields.Nested`` correctly serializes nested ``sets`` (:issue:`233`). Thanks :user:`traut`.

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

Features:

- Add ``marshmallow.validates_schema`` decorator for defining schema-level validators (:issue:`116`).
- Add ``marshmallow.validates`` decorator for defining field validators as Schema methods (:issue:`116`). Thanks :user:`philtay`.
- Performance improvements.
- Defining ``__marshallable__`` on complex objects is no longer necessary.
- Add ``fields.Constant``. Thanks :user:`kevinastone`.

Deprecation/Removals:

- Remove ``skip_missing`` class Meta option. By default, missing inputs are excluded from serialized output (:issue:`211`).
- Remove optional ``context`` parameter that gets passed to methods for ``Method`` fields.
- ``Schema.validator`` is deprecated. Use ``marshmallow.validates_schema`` instead.
- ``utils.get_func_name`` is removed. Use ``utils.get_callable_name`` instead.

Bug fixes:

- Fix serializing values from keyed tuple types (regression of :issue:`28`). Thanks :user:`makmanalp` for reporting.

Other changes:

- Remove unnecessary call to ``utils.get_value`` for ``Function`` and ``Method`` fields (:issue:`208`). Thanks :user:`jmcarp`.
- Serializing a collection without passing ``many=True`` will not result in an error. Be very careful to pass the ``many`` argument when necessary.

Support:

- Documentation: Update Flask and Peewee examples. Update Quickstart.

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

Features:

- Add useful ``__repr__`` methods to validators (:issue:`204`). Thanks :user:`philtay`.
- *Backwards-incompatible*: By default, ``NaN``, ``Infinity``, and ``-Infinity`` are invalid values for ``fields.Decimal``. Pass ``allow_nan=True`` to allow these values. Thanks :user:`philtay`.

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

Features:

- Errored fields will not appear in (de)serialized output dictionaries (:issue:`153`, :issue:`202`).
- Instantiate ``OPTIONS_CLASS`` in ``SchemaMeta``. This makes ``Schema.opts`` available in metaclass methods. It also causes validation to occur earlier (upon ``Schema`` class declaration rather than instantiation).
- Add ``SchemaMeta.get_declared_fields`` class method to support adding additional declared fields.

Deprecation/Removals:

- Remove ``allow_null`` parameter of ``fields.Nested`` (:issue:`203`).

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

Features:

- *Backwards-incompatible*: When ``many=True``, the errors dictionary returned by ``dump`` and ``load`` will be keyed on the indices of invalid items in the (de)serialized collection (:issue:`75`). Add ``index_errors=False`` on a Schema's ``class Meta`` options to disable this behavior.
- *Backwards-incompatible*: By default, fields will raise a ValidationError if the input is ``None``. The ``allow_none`` parameter can override this behavior.
- *Backwards-incompatible*: A ``Field's`` ``default`` parameter is only used if explicitly set and the field's value is missing in the input to `Schema.dump`. If not set, the key will not be present in the serialized output for missing values . This is the behavior for *all* fields. ``fields.Str`` no longer defaults to ``''``, ``fields.Int`` no longer defaults to ``0``, etc. (:issue:`199`). Thanks :user:`jmcarp` for the feedback.
- In ``strict`` mode, a ``ValidationError`` is raised. Error messages are accessed via the ``ValidationError's`` ``messages`` attribute (:issue:`128`).
- Add ``allow_none`` parameter to ``fields.Field``. If ``False`` (the default), validation fails when the field's value is ``None`` (:issue:`76`, :issue:`111`). If ``allow_none`` is ``True``, ``None`` is considered valid and will deserialize to ``None``.
- Schema-level validators can store error messages for multiple fields (:issue:`118`). Thanks :user:`ksesong` for the suggestion.
- Add ``pre_load``, ``post_load``, ``pre_dump``, and ``post_dump`` Schema method decorators for defining pre- and post- processing routines (:issue:`153`, :issue:`179`). Thanks :user:`davidism`, :user:`taion`, and :user:`jmcarp` for the suggestions and feedback. Thanks :user:`taion` for the implementation.
- Error message for ``required`` validation is configurable. (:issue:`78`). Thanks :user:`svenstaro` for the suggestion. Thanks :user:`0xDCA` for the implementation.
- Add ``load_from`` parameter to fields (:issue:`125`). Thanks :user:`hakjoon`.
- Add ``load_only`` and ``dump_only`` parameters to fields (:issue:`61`, :issue:`87`). Thanks :user:`philtay`.
- Add `missing` parameter to fields (:issue:`115`). Thanks :user:`philtay`.
- Schema validators can take an optional ``raw_data`` argument which contains raw input data, incl. data not specified in the schema (:issue:`127`). Thanks :user:`ryanlowe0`.
- Add ``validate.OneOf`` (:issue:`135`) and ``validate.ContainsOnly`` (:issue:`149`) validators. Thanks :user:`philtay`.
- Error messages for validators can be interpolated with `{input}` and other values (depending on the validator).
- ``fields.TimeDelta`` always serializes to an integer value in order to avoid rounding errors (:issue:`105`). Thanks :user:`philtay`.
- Add ``include`` class Meta option to support field names which are Python keywords (:issue:`139`). Thanks :user:`nickretallack` for the suggestion.
- ``exclude`` parameter is respected when used together with ``only`` parameter (:issue:`165`). Thanks :user:`lustdante` for the catch and patch.
- ``fields.List`` works as expected with generators and sets (:issue:`185`). Thanks :user:`sergey-aganezov-jr`.

Deprecation/Removals:

- ``MarshallingError`` and ``UnmarshallingError`` error are deprecated in favor of a single ``ValidationError`` (:issue:`160`).
- ``context`` argument passed to Method fields is deprecated. Use ``self.context`` instead (:issue:`184`).
- Remove ``ForcedError``.
- Remove support for generator functions that yield validators (:issue:`74`). Plain generators of validators are still supported.
- The ``Select/Enum`` field is deprecated in favor of using ``validate.OneOf`` validator (:issue:`135`).
- Remove legacy, pre-1.0 API (``Schema.data`` and ``Schema.errors`` properties) (:issue:`73`).
- Remove ``null`` value.

Other changes:

- ``Marshaller``, ``Unmarshaller`` were moved to ``marshmallow.marshalling``. These should be considered private API (:issue:`129`).
- Make ``allow_null=True`` the default for ``Nested`` fields. This will make ``None`` serialize to ``None`` rather than a dictionary with empty values (:issue:`132`). Thanks :user:`nickrellack` for the suggestion.

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

Bug fixes:

- Fix validation error message for ``fields.Decimal``.
- Allow error message for ``fields.Boolean`` to be customized with the ``error`` parameter (like other fields).