[change] Updated fallback choice fields

- Removed dependency for using get_field_value method to access
  value of a field.
- Simplified logic for choice fields
- Added FallbackDecimalField

README.rst

@@ -905,12 +905,6 @@ Model class inheriting ``UUIDModel`` which provides two additional fields:
 Which use respectively ``AutoCreatedField``, ``AutoLastModifiedField`` from ``model_utils.fields``
 (self-updating fields providing the creation date-time and the last modified date-time).
 
-``openwisp_utils.base.FallBackModelMixin``
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Model mixin that implements ``get_field_value`` method which can be used
-to get value of fallback fields.
-
 Custom Fields
 -------------
 
@@ -927,10 +921,10 @@ A model field which provides a random key or token, widely used across openwisp
 
 This field extends Django's `BooleanField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#booleanfield>`_
 and provides additional functionality for handling choices with a fallback value.
-The field will use the **fallback value** whenever the field is set to ``None``.
+The field will return the **fallback value** whenever the field is set to ``None``.
 
 This field is particularly useful when you want to present a choice between enabled
-and disabled options, with an additional "Default" option that reflects the fallback value.
+and disabled options.
 
 .. code-block:: python
 
@@ -940,9 +934,6 @@ and disabled options, with an additional "Default" option that reflects the fall
 
     class MyModel(models.Model):
         is_active = FallbackBooleanChoiceField(
-            null=True,
-            blank=True,
-            default=None,
             fallback=app_settings.IS_ACTIVE_FALLBACK,
         )
 
@@ -951,7 +942,7 @@ and disabled options, with an additional "Default" option that reflects the fall
 
 This field extends Django's `CharField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#charfield>`_
 and provides additional functionality for handling choices with a fallback value.
-The field will use the **fallback value** whenever the field is set to ``None``.
+The field will return the **fallback value** whenever the field is set to ``None``.
 
 .. code-block:: python
 
@@ -961,8 +952,6 @@ The field will use the **fallback value** whenever the field is set to ``None``.
 
     class MyModel(models.Model):
         is_first_name_required = FallbackCharChoiceField(
-            null=True,
-            blank=True,
             max_length=32,
             choices=(
                 ('disabled', _('Disabled')),
@@ -977,8 +966,7 @@ The field will use the **fallback value** whenever the field is set to ``None``.
 
 This field extends Django's `CharField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#charfield>`_
 and provides additional functionality for handling text fields with a fallback value.
-
-It allows populating the form with the fallback value when the actual value is set to ``null`` in the database.
+The field will return the **fallback value** whenever the field is set to ``None``.
 
 .. code-block:: python
 
@@ -988,8 +976,6 @@ It allows populating the form with the fallback value when the actual value is s
 
     class MyModel(models.Model):
         greeting_text = FallbackCharField(
-            null=True,
-            blank=True,
             max_length=200,
             fallback=app_settings.GREETING_TEXT,
         )
@@ -999,8 +985,7 @@ It allows populating the form with the fallback value when the actual value is s
 
 This field extends Django's `URLField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#urlfield>`_
 and provides additional functionality for handling URL fields with a fallback value.
-
-It allows populating the form with the fallback value when the actual value is set to ``null`` in the database.
+The field will return the **fallback value** whenever the field is set to ``None``.
 
 .. code-block:: python
 
@@ -1010,8 +995,6 @@ It allows populating the form with the fallback value when the actual value is s
 
     class MyModel(models.Model):
         password_reset_url = FallbackURLField(
-            null=True,
-            blank=True,
             max_length=200,
             fallback=app_settings.DEFAULT_PASSWORD_RESET_URL,
         )
@@ -1022,7 +1005,7 @@ It allows populating the form with the fallback value when the actual value is s
 This extends Django's `TextField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#django.db.models.TextField>`_
 and provides additional functionality for handling text fields with a fallback value.
 
-It allows populating the form with the fallback value when the actual value is set to ``null`` in the database.
+The field will returned the **fallback value** whenever the field is set to ``None``.
 
 .. code-block:: python
 
@@ -1032,8 +1015,6 @@ It allows populating the form with the fallback value when the actual value is s
 
     class MyModel(models.Model):
         extra_config = FallbackTextField(
-            null=True,
-            blank=True,
             max_length=200,
             fallback=app_settings.EXTRA_CONFIG,
         )
@@ -1044,7 +1025,7 @@ It allows populating the form with the fallback value when the actual value is s
 This extends Django's `PositiveIntegerField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#positiveintegerfield>`_
 and provides additional functionality for handling positive integer fields with a fallback value.
 
-It allows populating the form with the fallback value when the actual value is set to ``null`` in the database.
+The field will returned the **fallback value** whenever the field is set to ``None``.
 
 .. code-block:: python
 
@@ -1054,11 +1035,30 @@ It allows populating the form with the fallback value when the actual value is s
 
     class MyModel(models.Model):
         count = FallbackPositiveIntegerField(
-            blank=True,
-            null=True,
             fallback=app_settings.DEFAULT_COUNT,
         )
 
+``openwisp_utils.fields.FallbackDecimalField``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This extends Django's `DecimalField <https://docs.djangoproject.com/en/4.2/ref/models/fields/#decimalfield>`_
+and provides additional functionality for handling positive integer fields with a fallback value.
+
+The field will returned the **fallback value** whenever the field is set to ``None``.
+
+.. code-block:: python
+
+    from django.db import models
+    from openwisp_utils.fields import FallbackDecimalField
+    from myapp import settings as app_settings
+
+    class MyModel(models.Model):
+        price = FallbackDecimalField(
+            max_digits=4,
+            decimal_places=2,
+            fallback=app_settings.DEFAULT_price,
+        )
+
 Admin utilities
 ---------------
 

openwisp_utils/base.py

@@ -26,12 +26,3 @@ class TimeStampedEditableModel(UUIDModel):
 
     class Meta:
         abstract = True
-
-
-class FallbackModelMixin(object):
-    def get_field_value(self, field_name):
-        value = getattr(self, field_name)
-        field = self._meta.get_field(field_name)
-        if value is None and hasattr(field, 'fallback'):
-            return field.fallback
-        return value

openwisp_utils/fields.py

@@ -1,7 +1,9 @@
 from django import forms
 from django.db.models.fields import (
+    BLANK_CHOICE_DASH,
     BooleanField,
     CharField,
+    DecimalField,
     PositiveIntegerField,
     TextField,
     URLField,
@@ -39,6 +41,15 @@ def __init__(
 
 
 class FallbackMixin(object):
+    """
+    Returns the fallback value when the value of the field
+    is falsy (None or '').
+
+    It does not set the field's value to "None" when the value
+    is equal to the fallback value. This allows overriding of
+    the value when a user knows that the default will get changed.
+    """
+
     def __init__(self, fallback, *args, **kwargs):
         self.fallback = fallback
         opts = dict(blank=True, null=True, default=None)
@@ -50,17 +61,6 @@ def deconstruct(self):
         kwargs['fallback'] = self.fallback
         return (name, path, args, kwargs)
 
-
-class FallbackFromDbValueMixin:
-    """
-    Returns the fallback value when the value of the field
-    is falsy (None or '').
-
-    It does not set the field's value to "None" when the value
-    is equal to the fallback value. This allows overriding of
-    the value when a user knows that the default will get changed.
-    """
-
     def from_db_value(self, value, expression, connection):
         if value is None:
             return self.fallback
@@ -90,16 +90,12 @@ def clean(self, value, model_instance):
 
 class FallbackBooleanChoiceField(FallbackMixin, BooleanField):
     def formfield(self, **kwargs):
-        default_value = _('Enabled') if self.fallback else _('Disabled')
         kwargs.update(
             {
-                "form_class": forms.NullBooleanField,
+                "form_class": forms.BooleanField,
                 'widget': forms.Select(
-                    choices=[
-                        (
-                            '',
-                            _('Default') + f' ({default_value})',
-                        ),
+                    choices=BLANK_CHOICE_DASH
+                    + [
                         (True, _('Enabled')),
                         (False, _('Disabled')),
                     ]
@@ -110,14 +106,6 @@ def formfield(self, **kwargs):
 
 
 class FallbackCharChoiceField(FallbackMixin, CharField):
-    def get_choices(self, **kwargs):
-        for choice, value in self.choices:
-            if choice == self.fallback:
-                default = value
-                break
-        kwargs.update({'blank_choice': [('', _('Default') + f' ({default})')]})
-        return super().get_choices(**kwargs)
-
     def formfield(self, **kwargs):
         kwargs.update(
             {
@@ -127,15 +115,11 @@ def formfield(self, **kwargs):
         return super().formfield(**kwargs)
 
 
-class FallbackPositiveIntegerField(
-    FallbackMixin, FallbackFromDbValueMixin, PositiveIntegerField
-):
+class FallbackPositiveIntegerField(FallbackMixin, PositiveIntegerField):
     pass
 
 
-class FallbackCharField(
-    FallbackMixin, FalsyValueNoneMixin, FallbackFromDbValueMixin, CharField
-):
+class FallbackCharField(FallbackMixin, FalsyValueNoneMixin, CharField):
     """
     Populates the form with the fallback value
     if the value is set to null in the database.
@@ -144,9 +128,7 @@ class FallbackCharField(
     pass
 
 
-class FallbackURLField(
-    FallbackMixin, FalsyValueNoneMixin, FallbackFromDbValueMixin, URLField
-):
+class FallbackURLField(FallbackMixin, FalsyValueNoneMixin, URLField):
     """
     Populates the form with the fallback value
     if the value is set to null in the database.
@@ -155,21 +137,23 @@ class FallbackURLField(
     pass
 
 
-class FallbackTextField(
-    FallbackMixin, FalsyValueNoneMixin, FallbackFromDbValueMixin, TextField
-):
+class FallbackTextField(FallbackMixin, FalsyValueNoneMixin, TextField):
     """
     Populates the form with the fallback value
     if the value is set to null in the database.
     """
 
     def formfield(self, **kwargs):
-        kwargs.update({'form_class': FallbackTextFormField})
+        kwargs.update(
+            {
+                'form_class': forms.CharField,
+                'widget': forms.Textarea(
+                    attrs={'rows': 2, 'cols': 34, 'style': 'width:auto'}
+                ),
+            }
+        )
         return super().formfield(**kwargs)
 
 
-class FallbackTextFormField(forms.CharField):
-    def widget_attrs(self, widget):
-        attrs = super().widget_attrs(widget)
-        attrs.update({'rows': 2, 'cols': 34, 'style': 'width:auto'})
-        return attrs
+class FallbackDecimalField(FallbackMixin, DecimalField):
+    pass

openwisp_utils/metric_collection/tests/test_models.py

@@ -26,7 +26,6 @@ def setUp(self):
         # The post_migrate signal creates the first OpenwispVersion object
         # and uses the actual modules installed in the Python environment.
         # This would cause tests to fail when other modules are also installed.
-        # import ipdb; ipdb.set_trace()
         OpenwispVersion.objects.update(
             module_version={
                 'OpenWISP Version': '23.0.0a',

tests/test_project/migrations/0008_book_price.py

@@ -0,0 +1,26 @@
+# Generated by Django 4.2.7 on 2024-07-24 15:20
+
+from django.db import migrations
+import openwisp_utils.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("test_project", "0007_radiusaccounting_start_time_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="book",
+            name="price",
+            field=openwisp_utils.fields.FallbackDecimalField(
+                blank=True,
+                decimal_places=2,
+                default=None,
+                fallback=20.0,
+                max_digits=4,
+                null=True,
+            ),
+        ),
+    ]

tests/test_project/models.py

@@ -1,23 +1,19 @@
 from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.translation import gettext_lazy as _
-from openwisp_utils.base import (
-    FallbackModelMixin,
-    KeyField,
-    TimeStampedEditableModel,
-    UUIDModel,
-)
+from openwisp_utils.base import KeyField, TimeStampedEditableModel, UUIDModel
 from openwisp_utils.fields import (
     FallbackBooleanChoiceField,
     FallbackCharChoiceField,
     FallbackCharField,
+    FallbackDecimalField,
     FallbackPositiveIntegerField,
     FallbackTextField,
     FallbackURLField,
 )
 
 
-class Shelf(FallbackModelMixin, TimeStampedEditableModel):
+class Shelf(TimeStampedEditableModel):
     TYPES = (
         ('HORROR', 'HORROR'),
         ('FANTASY', 'FANTASY'),
@@ -67,6 +63,7 @@ class Book(TimeStampedEditableModel):
     name = models.CharField(_('name'), max_length=64)
     author = models.CharField(_('author'), max_length=64)
     shelf = models.ForeignKey('test_project.Shelf', on_delete=models.CASCADE)
+    price = FallbackDecimalField(max_digits=4, decimal_places=2, fallback=20.0)
 
     def __str__(self):
         return self.name
@@ -98,7 +95,7 @@ class RadiusAccounting(models.Model):
     )
 
 
-class OrganizationRadiusSettings(FallbackModelMixin, models.Model):
+class OrganizationRadiusSettings(models.Model):
     is_active = FallbackBooleanChoiceField(
         fallback=False,
     )