Marshmallow

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

Features:

- *Backwards-incompatible*: Validation does not occur on serialization (:issue:`1132`).
This significantly improves serialization performance.
- *Backwards-incompatible*: ``DateTime`` does not affect timezone information
on serialization and deserialization (:issue:`1234`, :pr:`1278`).
- Add ``NaiveDateTime`` and ``AwareDateTime`` to enforce timezone awareness
(:issue:`1234`, :pr:`1287`).
- *Backwards-incompatible*: ``List`` does not wrap single values in a list on
serialization (:pr:`1307`).
- *Backwards-incompatible*: ``Schema.handle_error`` receives ``many`` and ``partial`` as keyword arguments (:pr:`1321`).
- Use ``raise from`` more uniformly to improve stack traces (:pr:`1313`).
- Rename ``Nested.__schema`` to ``Nested._schema`` to prevent name mangling (:issue:`1289`).
- Performance improvements (:pr:`1309`).

Deprecations/Removals:

- ``LocalDateTime`` is removed (:issue:`1234`).
- ``marshmallow.utils.utc`` is removed. Use ``datetime.timezone.utc`` instead.

Bug fixes:

- Fix behavior of ``List(Nested("self"))`` (`779 (comment) <https://github.com/marshmallow-code/marshmallow/issues/779#issuecomment-396354987>`_).

Support:

- Document usage of ``validate.Regexp``'s usage ``re.search`` (:issue:`1285`). Thanks :user:`macdonaldezra`.

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

Features:

- Propagate ``only`` and ``exclude`` parameters to ``Nested`` fields
within ``List`` and ``Dict`` (:issue:`779`, :issue:`946`).
- Use ``email.utils.parsedate_to_datetime`` instead of conditionally
using dateutil for parsing RFC dates (:pr:`1246`).
- Use internal util functions instead of conditionally using dateutil
for parsing ISO 8601 datetimes, dates and times. Timezone info is now
correctly deserialized whether or not dateutil is installed. (:pr:`1265`)
- Improve error messages for ``validate.Range``.
- Use ``raise from error`` for better stack traces (:pr:`1254`). Thanks
:user:`fuhrysteve`.
- python-dateutil is no longer used. This resolves the inconsistent behavior
based on the presence of python-dateutil (:issue:`497`, :issue:`1234`).

Bug fixes:

- Fix method resolution for ``__init__`` method of ``fields.Email`` and
``fields.URL`` (:issue:`1268`). Thanks :user:`dursk` for the catch and patch.
- Includes bug fixes from 2.19.4 and 2.19.5.

Other changes:

- *Backwards-incompatible*: Rename ``fields.List.container`` to ``fields.List.inner``,
``fields.Dict.key_container`` to ``fields.Dict.key_field``, and
``fields.Dict.value_container`` to ``fields.Dict.value_field``.
- Switch to Azure Pipelines for CI (:issue:`1261`).

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

Features:

- *Backwards-incompatible*: ``many`` is passed as a keyword argument to methods decorated with
``pre_load``, ``post_load``, ``pre_dump``, ``post_dump``,
and ``validates_schema``. ``partial`` is passed as a keyword argument to
methods decorated with ``pre_load``, ``post_load`` and ``validates_schema``.
``**kwargs`` should be added to all decorated methods.
- Add ``min_inclusive`` and ``max_exclusive`` parameters to
``validate.Range`` (:issue:`1221`). Thanks :user:`kdop` for the PR.

Bug fixes:

- Fix propagation of ``partial`` to ``Nested`` containers (part of :issue:`779`).
- Includes bug fix from 2.19.3.

Other changes:

- *Backwards-incompatible*: Use keyword-only arguments (:issue:`1216`).

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

Support:

- *Backwards-incompatible*: Remove support for Python 2 (:issue:`1120`).
Only Python>=3.5 is supported.
Thank you :user:`rooterkyberian` for the suggestion and the PR.
- *Backwards-incompatible*: Remove special-casing in ``fields.List`` and
``fields.Tuple`` for accessing nested attributes (:pr:`1188`).
Use ``fields.List(fields.Pluck(...))`` instead.
- Add ``python_requires`` to ``setup.py`` (:pr:`1194`).
Thanks :user:`hugovk`.
- Upgrade syntax with ``pyupgrade`` in pre-commit (:pr:`1195`). Thanks
again :user:`hugovk`.

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

Features:

- Allow input value to be included in error messages
for a number of fields (:pr:`1129`). Thanks :user:`hdoupe` for the PR.
- Improve default error messages for ``OneOf`` and ``ContainsOnly``
(:issue:`885`). Thanks :user:`mcgfeller` for the suggestion
and :user:`maxalbert` for the PR.

Deprecations/Removals:

- Remove ``fields.FormattedString`` (:issue:`1141`). Use
``fields.Function`` or ``fields.Method`` instead.

Bug fixes:

- Includes bug fix from 2.19.2.

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

Features:

- Add ``fields.Tuple`` (:issue:`1103`) Thanks :user:`zblz` for the PR.
- Add ``fields.Mapping``, which makes it easier to support other
mapping types (e.g. ``OrderedDict``) (:issue:`1092`).
Thank :user:`sayanarijit` for the suggestion and the PR.