Fixed #11404. Added `FormSet.has_changed, for consistancy with Form.has_changed`. Thanks to michelts for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16773 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/forms/formsets.py

@@ -300,6 +300,12 @@ class BaseFormSet(StrAndUnicode):
         """
         pass
 
+    def has_changed(self):
+        """
+        Returns true if data in any form differs from initial.
+        """
+        return any(form.has_changed() for form in self)
+
     def add_fields(self, form, index):
         """A hook for adding extra fields on to each form instance."""
         if self.can_order:

docs/topics/forms/formsets.txt

@@ -150,6 +150,20 @@ As we can see, ``formset.errors`` is a list whose entries correspond to the
 forms in the formset. Validation was performed for each of the two forms, and
 the expected error message appears for the second item.
 
+We can also check if form data differs from the initial data (i.e. the form was
+sent without any data)::
+
+    >>> data = {
+    ...     'form-TOTAL_FORMS': u'1',
+    ...     'form-INITIAL_FORMS': u'0',
+    ...     'form-MAX_NUM_FORMS': u'',
+    ...     'form-0-title': u'',
+    ...     'form-0-pub_date': u'',
+    ... }
+    >>> formset = ArticleFormSet(data)
+    >>> formset.has_changed()
+    False
+
 .. _understanding-the-managementform:
 
 Understanding the ManagementForm

tests/regressiontests/forms/tests/formsets.py

@@ -73,9 +73,11 @@ class FormsFormsetTestCase(TestCase):
         self.assertTrue(formset.is_valid())
         self.assertEqual([form.cleaned_data for form in formset.forms], [{'votes': 100, 'choice': u'Calexico'}])
 
-        # If a FormSet was not passed any data, its is_valid method should return False.
+        # If a FormSet was not passed any data, its is_valid and has_changed
+        # methods should return False.
         formset = ChoiceFormSet()
         self.assertFalse(formset.is_valid())
+        self.assertFalse(formset.has_changed())
 
     def test_formset_validation(self):
         # FormSet instances can also have an error attribute if validation failed for
@@ -93,6 +95,31 @@ class FormsFormsetTestCase(TestCase):
         self.assertFalse(formset.is_valid())
         self.assertEqual(formset.errors, [{'votes': [u'This field is required.']}])
 
+    def test_formset_has_changed(self):
+        # FormSet instances has_changed method will be True if any data is
+        # passed to his forms, even if the formset didn't validate
+        data = {
+            'choices-TOTAL_FORMS': '1', # the number of forms rendered
+            'choices-INITIAL_FORMS': '0', # the number of forms with initial data
+            'choices-MAX_NUM_FORMS': '0', # max number of forms
+            'choices-0-choice': '',
+            'choices-0-votes': '',
+        }
+        blank_formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+        self.assertFalse(blank_formset.has_changed())
+
+        # invalid formset test
+        data['choices-0-choice'] = 'Calexico'
+        invalid_formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+        self.assertFalse(invalid_formset.is_valid())
+        self.assertTrue(invalid_formset.has_changed())
+
+        # valid formset test
+        data['choices-0-votes'] = '100'
+        valid_formset = ChoiceFormSet(data, auto_id=False, prefix='choices')
+        self.assertTrue(valid_formset.is_valid())
+        self.assertTrue(valid_formset.has_changed())
+
     def test_formset_initial_data(self):
         # We can also prefill a FormSet with existing data by providing an ``initial``
         # argument to the constructor. ``initial`` should be a list of dicts. By default,