* Use compat version of collections.abc.Mapping
Since the Mapping class will no longer be available to import directly
from the collections module in Python 3.8, we should use the
compatibility helper introduced in #6154 in the fields module.
* Alias and use compat version of collections.abc.MutableMapping
Since the MutableMapping class will no longer be available to import
directly from the collections module in Python 3.8, we should create an
alias for it in the compat module and use that instead.
The type bytes is available on all supported Pythons. On Python 2.7, it
is an alias for str, same as six.binary_type. Makes the code more
forward compatible with Python 3.
* Revert "Non-required fields with 'allow_null=True' should not imply a default value (#5639)"
This reverts commit 905a5579df.
Closes#5708
* Add test for allow_null + required=False
Ref #5708: allow_null should imply default=None, even for non-required fields.
* Re-order allow_null and default in field docs
default is prior to allow_null. allow_null implies an outgoing default=None.
* Adjust allow_null note.
Calling dict.keys() is unnecessary. The two are functionally equivalent
on modern Pythons.
Inspired by Lennart Regebro's talk "Prehistoric Patterns in Python" from
PyCon 2017.
https://www.youtube.com/watch?v=V5-JH23Vk0I
* Adding rounding parameter to DecimalField.
* Using standard `assert` instead of `self.fail()`.
* add testcase and PEP8 multilines fix
* flake8 fixes
* Use decimal module constants in tests.
* Add docs note for `rounding` parameter.
* Update remaing `include` calls
Missed as part of #5481 cleanup.
* Provide app_name in include_docs_urls
* Update remaining get_regex_pattern usages
* Allow functools.partial in is_simple_callable check
* Identify code that needs to be pulled out of/removed from compat.py
* Extract modern code from get_names_and_managers in compat.py and remove compat code
* Extract modern code from is_authenticated() in compat.py and remove.
* Extract modern code from is_anonymous() in compat.py and remove
* Extract modern code from get_related_model() from compat.py and remove
* Extract modern code from value_from_object() in compat.py and remove
* Update postgres compat
JSONField now always available.
* Remove DecimalValidator compat
* Remove get_remote_field compat
* Remove template_render compat
Plus isort.
* Remove set_many compat
* Remove include compat
## Description
The `choices` field for the `ChoiceField` class should be able to be edited after `ChoiceField.__init__` is called.
```
field = ChoiceField(choices=[1,2])
field.choices = [1] # Should no longer allow `2` as a choice
```
Currently, you must update `choices`, `grouped_choices`, and `choice_strings_to_values` to achieve this. This P/R keeps `grouped_choices` and `choice_strings_to_values` in sync whenever the `choices` are edited.
* Add regression test for #2505. Thanks @pySilver!
* Add regression test for #5087
* Revert "Cached the field's root and context property."
This reverts commit 792005806b.
Python Reference:
distutils.util.strtobool(val)
Convert a string representation of truth to true (1) or false (0).
True values are y, yes, t, true, on and 1; false values are n, no, f, false, off and 0. Raises ValueError if val is anything else.
