Fixed #26533 -- Renamed Widget._format_value() to format_value().

django/contrib/admin/widgets.py

@@ -376,7 +376,7 @@ class AdminURLFieldWidget(forms.URLInput):
     def render(self, name, value, attrs=None):
         html = super(AdminURLFieldWidget, self).render(name, value, attrs)
         if value:
-            value = force_text(self._format_value(value))
+            value = force_text(self.format_value(value))
             final_attrs = {'href': smart_urlquote(value)}
             html = format_html(
                 '<p class="url">{} <a{}>{}</a><br />{} {}</p>',

django/forms/widgets.py

@@ -15,6 +15,9 @@ from django.templatetags.static import static
 from django.utils import datetime_safe, formats, six
 from django.utils.datastructures import MultiValueDict
 from django.utils.dates import MONTHS
+from django.utils.deprecation import (
+    RemovedInDjango20Warning, RenameMethodsBase,
+)
 from django.utils.encoding import (
     force_str, force_text, python_2_unicode_compatible,
 )
@@ -174,7 +177,13 @@ class SubWidget(object):
         return self.parent_widget.render(*args)
 
 
-class Widget(six.with_metaclass(MediaDefiningClass)):
+class RenameWidgetMethods(MediaDefiningClass, RenameMethodsBase):
+    renamed_methods = (
+        ('_format_value', 'format_value', RemovedInDjango20Warning),
+    )
+
+
+class Widget(six.with_metaclass(RenameWidgetMethods)):
     needs_multipart_form = False  # Determines does this widget need multipart form
     is_localized = False
     is_required = False
@@ -248,7 +257,7 @@ class Input(Widget):
     """
     input_type = None  # Subclasses must define this.
 
-    def _format_value(self, value):
+    def format_value(self, value):
         if self.is_localized:
             return formats.localize_input(value)
         return value
@@ -259,7 +268,7 @@ class Input(Widget):
         final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)
         if value != '':
             # Only add the 'value' attribute if a value is non-empty.
-            final_attrs['value'] = force_text(self._format_value(value))
+            final_attrs['value'] = force_text(self.format_value(value))
         return format_html('<input{} />', flatatt(final_attrs))
 
 
@@ -443,7 +452,7 @@ class DateTimeBaseInput(TextInput):
         super(DateTimeBaseInput, self).__init__(attrs)
         self.format = format if format else None
 
-    def _format_value(self, value):
+    def format_value(self, value):
         return formats.localize_input(value, self.format or formats.get_format(self.format_key)[0])
 
 

docs/internals/deprecation.txt

@@ -163,6 +163,8 @@ details on these changes.
 * In multi-table inheritance, implicit promotion of a ``OneToOneField`` to a
   ``parent_link`` will be removed.
 
+* Support for ``Widget._format_value()`` will be removed.
+
 .. _deprecation-removed-in-1.10:
 
 1.10

docs/ref/forms/widgets.txt

@@ -228,6 +228,17 @@ foundation for custom widgets.
            In older versions, this attribute was only defined on the date
            and time widgets (as ``False``).
 
+    .. method:: format_value(value)
+
+        Cleans and returns a value for use in the widget template. ``value``
+        isn't guaranteed to be valid input, therefore subclass implementations
+        should program defensively.
+
+        .. versionchanged:: 1.10
+
+            In older versions, this method is a private API named
+            ``_format_value()``. The old name will work until Django 2.0.
+
     .. method:: id_for_label(self, id_)
 
         Returns the HTML ID attribute of this widget for use by a ``<label>``,

docs/releases/1.10.txt

@@ -983,6 +983,10 @@ Miscellaneous
 * In multi-table inheritance, implicit promotion of a ``OneToOneField`` to a
   ``parent_link`` is deprecated. Add ``parent_link=True`` to such fields.
 
+* The private API ``Widget._format_value()`` is made public and renamed to
+  :meth:`~django.forms.Widget.format_value`. The old name will work
+  through a deprecation period.
+
 .. _removed-features-1.10:
 
 Features removed in 1.10

tests/forms_tests/field_tests/test_datefield.py

@@ -69,7 +69,7 @@ class DateFieldTest(SimpleTestCase):
             'mydate_year': '2008',
             'mydate_month': '4',
             'mydate_day': '1',
-            'initial-mydate': HiddenInput()._format_value(date(2008, 4, 1)),
+            'initial-mydate': HiddenInput().format_value(date(2008, 4, 1)),
         }, initial={'mydate': date(2008, 4, 1)})
         self.assertFalse(b.has_changed())
 
@@ -77,7 +77,7 @@ class DateFieldTest(SimpleTestCase):
             'mydate_year': '2008',
             'mydate_month': '4',
             'mydate_day': '22',
-            'initial-mydate': HiddenInput()._format_value(date(2008, 4, 1)),
+            'initial-mydate': HiddenInput().format_value(date(2008, 4, 1)),
         }, initial={'mydate': date(2008, 4, 1)})
         self.assertTrue(b.has_changed())
 
@@ -85,7 +85,7 @@ class DateFieldTest(SimpleTestCase):
             'mydate_year': '2008',
             'mydate_month': '4',
             'mydate_day': '22',
-            'initial-mydate': HiddenInput()._format_value(date(2008, 4, 1)),
+            'initial-mydate': HiddenInput().format_value(date(2008, 4, 1)),
         }, initial={'mydate': date(2008, 4, 22)})
         self.assertTrue(b.has_changed())
 
@@ -93,7 +93,7 @@ class DateFieldTest(SimpleTestCase):
             'mydate_year': '2008',
             'mydate_month': '4',
             'mydate_day': '22',
-            'initial-mydate': HiddenInput()._format_value(date(2008, 4, 22)),
+            'initial-mydate': HiddenInput().format_value(date(2008, 4, 22)),
         }, initial={'mydate': date(2008, 4, 1)})
         self.assertFalse(b.has_changed())