Fixed #22628 -- Took initial forms into account when combining FormSet.min_num and FormSet.extra.

Forwardport of 79f15ab1ef from stable/1.7.x

django/forms/formsets.py

@@ -114,7 +114,7 @@ class BaseFormSet(object):
             return min(self.management_form.cleaned_data[TOTAL_FORM_COUNT], self.absolute_max)
         else:
             initial_forms = self.initial_form_count()
-            total_forms = initial_forms + self.extra
+            total_forms = max(initial_forms, self.min_num) + self.extra
             # Allow all existing related objects/inlines to be displayed,
             # but don't allow extra beyond max_num.
             if initial_forms > self.max_num >= 0:
@@ -158,8 +158,9 @@ class BaseFormSet(object):
                 defaults['initial'] = self.initial[i]
             except IndexError:
                 pass
-        # Allow extra forms to be empty.
-        if i >= self.initial_form_count():
+        # Allow extra forms to be empty, unless they're part of
+        # the minimum forms.
+        if i >= self.initial_form_count() and i >= self.min_num:
             defaults['empty_permitted'] = True
         defaults.update(kwargs)
         form = self.form(**defaults)
@@ -422,7 +423,6 @@ def formset_factory(form, formset=BaseFormSet, extra=1, can_order=False,
     # limit is simply max_num + DEFAULT_MAX_NUM (which is 2*DEFAULT_MAX_NUM
     # if max_num is None in the first place)
     absolute_max = max_num + DEFAULT_MAX_NUM
-    extra += min_num
     attrs = {'form': form, 'extra': extra,
              'can_order': can_order, 'can_delete': can_delete,
              'min_num': min_num, 'max_num': max_num,

tests/admin_inlines/tests.py

@@ -247,7 +247,6 @@ class TestInline(TestCase):
     def test_custom_min_num(self):
         """
         Ensure that get_min_num is called and used correctly.
-        See #22628 - this will change when that's fixed.
         """
         bt_head = BinaryTree.objects.create(name="Tree Head")
         BinaryTree.objects.create(name="First Child", parent=bt_head)
@@ -277,7 +276,7 @@ class TestInline(TestCase):
         request.user = User(username='super', is_superuser=True)
         response = modeladmin.changeform_view(request, object_id=str(bt_head.id))
         self.assertContains(response, min_forms % 5)
-        self.assertContains(response, total_forms % 9)
+        self.assertContains(response, total_forms % 8)
 
     def test_inline_nonauto_noneditable_pk(self):
         response = self.client.get('/admin/admin_inlines/author/add/')

tests/forms_tests/tests/test_formsets.py

@@ -216,7 +216,7 @@ class FormsFormsetTestCase(TestCase):
 
     def test_min_num_displaying_more_than_one_blank_form(self):
         # We can also display more than 1 empty form passing min_num argument
-        # to formset_factory. It will increment the extra argument
+        # to formset_factory. It will (essentially) increment the extra argument
         ChoiceFormSet = formset_factory(Choice, extra=1, min_num=1)
 
         formset = ChoiceFormSet(auto_id=False, prefix='choices')
@@ -225,6 +225,10 @@ class FormsFormsetTestCase(TestCase):
         for form in formset.forms:
             form_output.append(form.as_ul())
 
+        # Min_num forms are required; extra forms can be empty.
+        self.assertFalse(formset.forms[0].empty_permitted)
+        self.assertTrue(formset.forms[1].empty_permitted)
+
         self.assertHTMLEqual('\n'.join(form_output), """<li>Choice: <input type="text" name="choices-0-choice" /></li>
 <li>Votes: <input type="number" name="choices-0-votes" /></li>
 <li>Choice: <input type="text" name="choices-1-choice" /></li>

tests/generic_inline_admin/tests.py

@@ -204,8 +204,7 @@ class GenericInlineAdminParametersTest(TestCase):
 
     def testMinNumParam(self):
         """
-        With extra=3 and min_num=2, there should be six forms.
-        See #22628 - this will change when that's fixed.
+        With extra=3 and min_num=2, there should be five forms.
         """
         class MinNumInline(GenericTabularInline):
             model = Media
@@ -220,7 +219,7 @@ class GenericInlineAdminParametersTest(TestCase):
         request.user = User(username='super', is_superuser=True)
         response = modeladmin.changeform_view(request, object_id=str(e.pk))
         formset = response.context_data['inline_admin_formsets'][0].formset
-        self.assertEqual(formset.total_form_count(), 6)
+        self.assertEqual(formset.total_form_count(), 5)
         self.assertEqual(formset.initial_form_count(), 1)
 
 

tests/model_formsets/tests.py

@@ -395,13 +395,12 @@ class ModelFormsetTest(TestCase):
 
     def test_min_num_with_existing(self):
         # Test the behavior of min_num with existing objects.
-        # See #22628 - this will change when that's fixed.
         Author.objects.create(name='Charles Baudelaire')
         qs = Author.objects.all()
 
         AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=0, min_num=1)
         formset = AuthorFormSet(queryset=qs)
-        self.assertEqual(len(formset.forms), 2)
+        self.assertEqual(len(formset.forms), 1)
 
     def test_custom_save_method(self):
         class PoetForm(forms.ModelForm):