Fixed #24428 -- Fixed has_changed for fields with coercion

Thanks Carsten Fuchs for the report.

django/forms/fields.py

@@ -195,6 +195,7 @@ class Field(six.with_metaclass(RenameFieldMethods, object)):
             data = self.to_python(data)
             if hasattr(self, '_coerce'):
                 data = self._coerce(data)
+                initial_value = self._coerce(initial_value)
         except ValidationError:
             return True
         data_value = data if data is not None else ''

tests/forms_tests/tests/test_fields.py

@@ -1082,6 +1082,7 @@ class FieldsTests(SimpleTestCase):
         f = TypedChoiceField(choices=[(1, "+1"), (-1, "-1")], coerce=int, required=True)
         self.assertFalse(f.has_changed(None, ''))
         self.assertFalse(f.has_changed(1, '1'))
+        self.assertFalse(f.has_changed('1', '1'))
 
     def test_typedchoicefield_special_coerce(self):
         """

tests/model_forms/models.py

@@ -106,6 +106,23 @@ class Publication(models.Model):
         return self.title
 
 
+def default_mode():
+    return 'di'
+
+
+def default_category():
+    return 3
+
+
+class PublicationDefaults(models.Model):
+    MODE_CHOICES = (('di', 'direct'), ('de', 'delayed'))
+    CATEGORY_CHOICES = ((1, 'Games'), (2, 'Comics'), (3, 'Novel'))
+    title = models.CharField(max_length=30)
+    date_published = models.DateField(default=datetime.date.today)
+    mode = models.CharField(max_length=2, choices=MODE_CHOICES, default=default_mode)
+    category = models.IntegerField(choices=CATEGORY_CHOICES, default=default_category)
+
+
 class Author(models.Model):
     publication = models.OneToOneField(Publication, null=True, blank=True)
     full_name = models.CharField(max_length=255)

tests/model_forms/tests.py

@@ -28,8 +28,9 @@ from .models import (
     CustomErrorMessage, CustomFF, CustomFieldForExclusionModel, DateTimePost,
     DerivedBook, DerivedPost, Document, ExplicitPK, FilePathModel,
     FlexibleDatePost, Homepage, ImprovedArticle, ImprovedArticleWithParentLink,
-    Inventory, Person, Photo, Post, Price, Product, Publication, Student,
-    StumpJoke, TextFile, Triple, Writer, WriterProfile, test_images,
+    Inventory, Person, Photo, Post, Price, Product, Publication,
+    PublicationDefaults, Student, StumpJoke, TextFile, Triple, Writer,
+    WriterProfile, test_images,
 )
 
 if test_images:
@@ -2282,6 +2283,41 @@ class OtherModelFormTests(TestCase):
         </select></p>"""
             % {'blue_pk': colour.pk})
 
+    def test_callable_field_default(self):
+        class PublicationDefaultsForm(forms.ModelForm):
+            class Meta:
+                model = PublicationDefaults
+                fields = '__all__'
+
+        form = PublicationDefaultsForm()
+        self.assertHTMLEqual(
+            form.as_p(),
+            """<p><label for="id_title">Title:</label> <input id="id_title" maxlength="30" name="title" type="text" /></p>
+               <p><label for="id_date_published">Date published:</label>
+                    <input id="id_date_published" name="date_published" type="text" value="2015-03-04" />
+                    <input id="initial-id_date_published" name="initial-date_published" type="hidden" value="2015-03-04" /></p>
+               <p><label for="id_mode">Mode:</label> <select id="id_mode" name="mode">
+                    <option value="di" selected="selected">direct</option>
+                    <option value="de">delayed</option></select>
+                    <input id="initial-id_mode" name="initial-mode" type="hidden" value="di" /></p>
+               <p><label for="id_category">Category:</label> <select id="id_category" name="category">
+                    <option value="1">Games</option>
+                    <option value="2">Comics</option>
+                    <option value="3" selected="selected">Novel</option></select>
+                    <input id="initial-id_category" name="initial-category" type="hidden" value="3" />"""
+        )
+        empty_data = {
+            'title': '',
+            'date_published': '2015-03-04',
+            'initial-date_published': '2015-03-04',
+            'mode': 'di',
+            'initial-mode': 'di',
+            'category': '3',
+            'initial-category': '3',
+        }
+        bound_form = PublicationDefaultsForm(empty_data)
+        self.assertFalse(bound_form.has_changed())
+
 
 class ModelFormCustomErrorTests(TestCase):
     def test_custom_error_messages(self):