Z3c.form

----------------

- Nothing changed yet.

----------------

- HTMLFormElement.attributes: Allow to extend HTML attributes programmatically.

----------------

- Add support for Python 3.11.

- Drop support for Python 2.7, 3.5, 3.6.

- Drop deprecated support for ``python setup.py test``.

- HTMLFormElement.addClass: Improve removal of duplicates. It's now possible to
add multiple classes as whitespace separated string and still detect class
duplicates.

----------------

- Add support for Python 3.10.

- Update tests to ``lxml > 4.7``, thus requiring at least that version.
(`107 <https://github.com/zopefoundation/z3c.form/issues/107>`_)

- Remove unused ``ISubformFactory.
(`110 <https://github.com/zopefoundation/z3c.form/issues/110>`_)
[petschki]

----------------

- Fix ``MultiConverter.toFieldValue`` tuple typed field support
(when ``field._type`` is a tuple of types, not a single type).

- Add Python 3.9 compatibility and testing.

- Apply ``zopefoundation.meta`` config

- Fix tests for the ``zope.schema.Bool`` required default change.

- Fix tests for the ``zope.interface repr()`` change.

- Fix compatibility with changed repeat syntax.
Fixes `issue 94 <https://github.com/zopefoundation/z3c.form/issues/94>`_.

- Some fixes in spanish translation.
[erral]

- Drop support for Python 3.4.

- Add support for Python 3.8b4.

- Try to fix the buggy hidden mode behaviour of checkbox widgets.
Fixes `issue 89 <https://github.com/zopefoundation/z3c.form/issues/89>`_.

------------------

- Fix an edge case when field ``missing_value`` is not None but a custom
value that works as ``None``.
That ended up calling ``zope.i18n NumberFormat.format`` with ``None`` what
then failed.