[1.7.x] Fixed #17642 -- Added min_num support to modelformsets, inlines, and the admin.

Thanks Stephen Burrows for work on the patch as well.

django/contrib/admin/checks.py

@@ -850,6 +850,7 @@ class InlineModelAdminChecks(BaseModelAdminChecks):
         errors.extend(self._check_exclude_of_parent_model(cls, parent_model))
         errors.extend(self._check_extra(cls))
         errors.extend(self._check_max_num(cls))
+        errors.extend(self._check_min_num(cls))
         errors.extend(self._check_formset(cls))
         return errors
 
@@ -909,12 +910,22 @@ class InlineModelAdminChecks(BaseModelAdminChecks):
         else:
             return []
 
+    def _check_min_num(self, cls):
+        """ Check that min_num is an integer. """
+
+        if cls.min_num is None:
+            return []
+        elif not isinstance(cls.min_num, int):
+            return must_be('an integer', option='min_num', obj=cls, id='admin.E205')
+        else:
+            return []
+
     def _check_formset(self, cls):
         """ Check formset is a subclass of BaseModelFormSet. """
 
         if not issubclass(cls.formset, BaseModelFormSet):
             return must_inherit_from(parent='BaseModelFormSet', option='formset',
-                                     obj=cls, id='admin.E205')
+                                     obj=cls, id='admin.E206')
         else:
             return []
 

django/contrib/admin/options.py

@@ -1707,6 +1707,7 @@ class InlineModelAdmin(BaseModelAdmin):
     fk_name = None
     formset = BaseInlineFormSet
     extra = 3
+    min_num = None
     max_num = None
     template = None
     verbose_name = None
@@ -1739,6 +1740,10 @@ class InlineModelAdmin(BaseModelAdmin):
         """Hook for customizing the number of extra inline forms."""
         return self.extra
 
+    def get_min_num(self, request, obj=None, **kwargs):
+        """Hook for customizing the min number of inline forms."""
+        return self.min_num
+
     def get_max_num(self, request, obj=None, **kwargs):
         """Hook for customizing the max number of extra inline forms."""
         return self.max_num
@@ -1770,6 +1775,7 @@ class InlineModelAdmin(BaseModelAdmin):
             "exclude": exclude,
             "formfield_callback": partial(self.formfield_for_dbfield, request=request),
             "extra": self.get_extra(request, obj, **kwargs),
+            "min_num": self.get_min_num(request, obj, **kwargs),
             "max_num": self.get_max_num(request, obj, **kwargs),
             "can_delete": can_delete,
         }

django/contrib/contenttypes/admin.py

@@ -119,6 +119,7 @@ class GenericInlineModelAdmin(InlineModelAdmin):
             "can_delete": can_delete,
             "can_order": False,
             "fields": fields,
+            "min_num": self.min_num,
             "max_num": self.max_num,
             "exclude": exclude
         }

django/contrib/contenttypes/forms.py

@@ -56,9 +56,9 @@ def generic_inlineformset_factory(model, form=ModelForm,
                                   ct_field="content_type", fk_field="object_id",
                                   fields=None, exclude=None,
                                   extra=3, can_order=False, can_delete=True,
-                                  max_num=None,
-                                  formfield_callback=None, validate_max=False,
-                                  for_concrete_model=True):
+                                  max_num=None, formfield_callback=None,
+                                  validate_max=False, for_concrete_model=True,
+                                  min_num=None, validate_min=False):
     """
     Returns a ``GenericInlineFormSet`` for the given kwargs.
 
@@ -81,7 +81,8 @@ def generic_inlineformset_factory(model, form=ModelForm,
                                    formset=formset,
                                    extra=extra, can_delete=can_delete, can_order=can_order,
                                    fields=fields, exclude=exclude, max_num=max_num,
-                                   validate_max=validate_max)
+                                   validate_max=validate_max, min_num=min_num,
+                                   validate_min=validate_min)
     FormSet.ct_field = ct_field
     FormSet.ct_fk_field = fk_field
     FormSet.for_concrete_model = for_concrete_model

django/forms/models.py

@@ -810,7 +810,8 @@ def modelformset_factory(model, form=ModelForm, formfield_callback=None,
                          formset=BaseModelFormSet, extra=1, can_delete=False,
                          can_order=False, max_num=None, fields=None, exclude=None,
                          widgets=None, validate_max=False, localized_fields=None,
-                         labels=None, help_texts=None, error_messages=None):
+                         labels=None, help_texts=None, error_messages=None,
+                         min_num=None, validate_min=False):
     """
     Returns a FormSet class for the given Django model class.
     """
@@ -833,9 +834,9 @@ def modelformset_factory(model, form=ModelForm, formfield_callback=None,
                              formfield_callback=formfield_callback,
                              widgets=widgets, localized_fields=localized_fields,
                              labels=labels, help_texts=help_texts, error_messages=error_messages)
-    FormSet = formset_factory(form, formset, extra=extra, max_num=max_num,
+    FormSet = formset_factory(form, formset, extra=extra, min_num=min_num, max_num=max_num,
                               can_order=can_order, can_delete=can_delete,
-                              validate_max=validate_max)
+                              validate_min=validate_min, validate_max=validate_max)
     FormSet.model = model
     return FormSet
 
@@ -979,7 +980,8 @@ def inlineformset_factory(parent_model, model, form=ModelForm,
                           fields=None, exclude=None, extra=3, can_order=False,
                           can_delete=True, max_num=None, formfield_callback=None,
                           widgets=None, validate_max=False, localized_fields=None,
-                          labels=None, help_texts=None, error_messages=None):
+                          labels=None, help_texts=None, error_messages=None,
+                          min_num=None, validate_min=False):
     """
     Returns an ``InlineFormSet`` for the given kwargs.
 
@@ -999,8 +1001,10 @@ def inlineformset_factory(parent_model, model, form=ModelForm,
         'can_order': can_order,
         'fields': fields,
         'exclude': exclude,
+        'min_num': min_num,
         'max_num': max_num,
         'widgets': widgets,
+        'validate_min': validate_min,
         'validate_max': validate_max,
         'localized_fields': localized_fields,
         'labels': labels,

docs/ref/checks.txt

@@ -204,7 +204,8 @@ inline on a :class:`~django.contrib.admin.ModelAdmin`.
 * **admin.E202**: ``<model>`` has no ForeignKey to ``<parent model>``./``<model>`` has more than one ForeignKey to ``<parent model>``.
 * **admin.E203**: The value of ``extra`` must be an integer.
 * **admin.E204**: The value of ``max_num`` must be an integer.
-* **admin.E205**: The value of ``formset`` must inherit from ``BaseModelFormSet``.
+* **admin.E205**: The value of ``min_num`` must be an integer.
+* **admin.E206**: The value of ``formset`` must inherit from ``BaseModelFormSet``.
 
 GenericInlineModelAdmin
 ~~~~~~~~~~~~~~~~~~~~~~~

docs/ref/contrib/admin/index.txt

@@ -1994,6 +1994,16 @@ The ``InlineModelAdmin`` class adds:
     :meth:`InlineModelAdmin.get_max_num` also allows you to customize the
     maximum number of extra forms.
 
+.. attribute:: InlineModelAdmin.min_num
+
+    .. versionadded:: 1.7
+
+    This controls the minimum number of forms to show in the inline.
+    See :func:`~django.forms.models.modelformset_factory` for more information.
+
+    :meth:`InlineModelAdmin.get_min_num` also allows you to customize the
+    minimum number of displayed forms.
+
 .. attribute:: InlineModelAdmin.raw_id_fields
 
     By default, Django's admin uses a select-box interface (<select>) for
@@ -2074,6 +2084,16 @@ The ``InlineModelAdmin`` class adds:
                     return max_num - 5
                 return max_num
 
+.. method:: InlineModelAdmin.get_min_num(request, obj=None, **kwargs)
+
+    .. versionadded:: 1.7
+
+    Returns the minimum number of inline forms to use. By default,
+    returns the :attr:`InlineModelAdmin.min_num` attribute.
+
+    Override this method to programmatically determine the minimum number of
+    inline forms. For example, this may be based on the model instance
+    (passed as the keyword argument ``obj``).
 
 Working with a model with two or more foreign keys to the same parent model
 ---------------------------------------------------------------------------

docs/ref/contrib/contenttypes.txt

@@ -500,7 +500,7 @@ The :mod:`django.contrib.contenttypes.forms` module provides:
 
         This class used to be defined in ``django.contrib.contenttypes.generic``.
 
-.. function:: generic_inlineformset_factory(model, form=ModelForm, formset=BaseGenericInlineFormSet, ct_field="content_type", fk_field="object_id", fields=None, exclude=None, extra=3, can_order=False, can_delete=True, max_num=None, formfield_callback=None, validate_max=False, for_concrete_model=True)
+.. function:: generic_inlineformset_factory(model, form=ModelForm, formset=BaseGenericInlineFormSet, ct_field="content_type", fk_field="object_id", fields=None, exclude=None, extra=3, can_order=False, can_delete=True, max_num=None, formfield_callback=None, validate_max=False, for_concrete_model=True, min_num=None, validate_min=False)
 
     Returns a ``GenericInlineFormSet`` using
     :func:`~django.forms.models.modelformset_factory`.
@@ -521,6 +521,10 @@ The :mod:`django.contrib.contenttypes.forms` module provides:
 
         This function used to be defined in ``django.contrib.contenttypes.generic``.
 
+    .. versionchanged:: 1.7
+
+        ``min_num`` and ``validate_min`` were added.
+
 
 .. module:: django.contrib.contenttypes.admin
 

docs/ref/forms/models.txt

@@ -45,7 +45,7 @@ Model Form Functions
     The ``localized_fields``, ``labels``, ``help_texts``, and
     ``error_messages`` parameters were added.
 
-.. function:: modelformset_factory(model, form=ModelForm, formfield_callback=None, formset=BaseModelFormSet, extra=1, can_delete=False, can_order=False, max_num=None, fields=None, exclude=None, widgets=None, validate_max=False, localized_fields=None, labels=None, help_texts=None, error_messages=None)
+.. function:: modelformset_factory(model, form=ModelForm, formfield_callback=None, formset=BaseModelFormSet, extra=1, can_delete=False, can_order=False, max_num=None, fields=None, exclude=None, widgets=None, validate_max=False, localized_fields=None, labels=None, help_texts=None, error_messages=None, min_num=None, validate_min=False)
 
     Returns a ``FormSet`` class for the given ``model`` class.
 
@@ -66,7 +66,7 @@ Model Form Functions
         The ``widgets``, ``validate_max``, ``localized_fields``, ``labels``,
         ``help_texts``, and ``error_messages`` parameters were added.
 
-.. function:: inlineformset_factory(parent_model, model, form=ModelForm, formset=BaseInlineFormSet, fk_name=None, fields=None, exclude=None, extra=3, can_order=False, can_delete=True, max_num=None, formfield_callback=None, widgets=None, validate_max=False, localized_fields=None, labels=None, help_texts=None, error_messages=None)
+.. function:: inlineformset_factory(parent_model, model, form=ModelForm, formset=BaseInlineFormSet, fk_name=None, fields=None, exclude=None, extra=3, can_order=False, can_delete=True, max_num=None, formfield_callback=None, widgets=None, validate_max=False, localized_fields=None, labels=None, help_texts=None, error_messages=None, min_num=None, validate_min=False)
 
     Returns an ``InlineFormSet`` using :func:`modelformset_factory` with
     defaults of ``formset=``:class:`~django.forms.models.BaseInlineFormSet`,

tests/admin_inlines/tests.py

@@ -1,13 +1,14 @@
 from __future__ import unicode_literals
 
+from django.contrib.admin import TabularInline, ModelAdmin
 from django.contrib.admin.tests import AdminSeleniumWebDriverTestCase
 from django.contrib.admin.helpers import InlineAdminForm
 from django.contrib.auth.models import User, Permission
 from django.contrib.contenttypes.models import ContentType
-from django.test import TestCase, override_settings
+from django.test import TestCase, override_settings, RequestFactory
 
 # local test models
-from .admin import InnerInline
+from .admin import InnerInline, site as admin_site
 from .models import (Holder, Inner, Holder2, Inner2, Holder3, Inner3, Person,
     OutfitItem, Fashionista, Teacher, Parent, Child, Author, Book, Profile,
     ProfileCollection, ParentModelWithCustomPk, ChildModel1, ChildModel2,
@@ -28,6 +29,7 @@ class TestInline(TestCase):
 
         result = self.client.login(username='super', password='secret')
         self.assertEqual(result, True)
+        self.factory = RequestFactory()
 
     def tearDown(self):
         self.client.logout()
@@ -221,6 +223,62 @@ class TestInline(TestCase):
         self.assertContains(response, max_forms_input % 2)
         self.assertContains(response, total_forms_hidden)
 
+    def test_min_num(self):
+        """
+        Ensure that min_num and extra determine number of forms.
+        """
+        class MinNumInline(TabularInline):
+            model = BinaryTree
+            min_num = 2
+            extra = 3
+
+        modeladmin = ModelAdmin(BinaryTree, admin_site)
+        modeladmin.inlines = [MinNumInline]
+
+        min_forms = '<input id="id_binarytree_set-MIN_NUM_FORMS" name="binarytree_set-MIN_NUM_FORMS" type="hidden" value="2" />'
+        total_forms = '<input id="id_binarytree_set-TOTAL_FORMS" name="binarytree_set-TOTAL_FORMS" type="hidden" value="5" />'
+
+        request = self.factory.get('/admin/admin_inlines/binarytree/add/')
+        request.user = User(username='super', is_superuser=True)
+        response = modeladmin.changeform_view(request)
+        self.assertContains(response, min_forms)
+        self.assertContains(response, total_forms)
+
+    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)
+
+        class MinNumInline(TabularInline):
+            model = BinaryTree
+            extra = 3
+
+            def get_min_num(self, request, obj=None, **kwargs):
+                if obj:
+                    return 5
+                return 2
+
+        modeladmin = ModelAdmin(BinaryTree, admin_site)
+        modeladmin.inlines = [MinNumInline]
+
+        min_forms = '<input id="id_binarytree_set-MIN_NUM_FORMS" name="binarytree_set-MIN_NUM_FORMS" type="hidden" value="%d" />'
+        total_forms = '<input id="id_binarytree_set-TOTAL_FORMS" name="binarytree_set-TOTAL_FORMS" type="hidden" value="%d" />'
+
+        request = self.factory.get('/admin/admin_inlines/binarytree/add/')
+        request.user = User(username='super', is_superuser=True)
+        response = modeladmin.changeform_view(request)
+        self.assertContains(response, min_forms % 2)
+        self.assertContains(response, total_forms % 5)
+
+        request = self.factory.get("/admin/admin_inlines/binarytree/%d/" % bt_head.id)
+        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)
+
     def test_inline_nonauto_noneditable_pk(self):
         response = self.client.get('/admin/admin_inlines/author/add/')
         self.assertContains(response,

tests/generic_inline_admin/admin.py

@@ -1,8 +1,8 @@
 from django.contrib import admin
 from django.contrib.contenttypes.admin import GenericTabularInline
 
-from .models import (Media, PhoneNumber, Episode, EpisodeExtra, Contact,
-    Category, EpisodePermanent, EpisodeMaxNum)
+from .models import (Media, PhoneNumber, Episode, Contact,
+    Category, EpisodePermanent)
 
 
 site = admin.AdminSite(name="admin")
@@ -18,17 +18,6 @@ class EpisodeAdmin(admin.ModelAdmin):
     ]
 
 
-class MediaExtraInline(GenericTabularInline):
-    model = Media
-    extra = 0
-
-
-class MediaMaxNumInline(GenericTabularInline):
-    model = Media
-    extra = 5
-    max_num = 2
-
-
 class PhoneNumberInline(GenericTabularInline):
     model = PhoneNumber
 
@@ -39,8 +28,6 @@ class MediaPermanentInline(GenericTabularInline):
 
 
 site.register(Episode, EpisodeAdmin)
-site.register(EpisodeExtra, inlines=[MediaExtraInline])
-site.register(EpisodeMaxNum, inlines=[MediaMaxNumInline])
 site.register(Contact, inlines=[PhoneNumberInline])
 site.register(Category)
 site.register(EpisodePermanent, inlines=[MediaPermanentInline])

tests/generic_inline_admin/models.py

@@ -27,26 +27,6 @@ class Media(models.Model):
     def __str__(self):
         return self.url
 
-#
-# These models let us test the different GenericInline settings at
-# different urls in the admin site.
-#
-
-#
-# Generic inline with extra = 0
-#
-
-
-class EpisodeExtra(Episode):
-    pass
-
-
-#
-# Generic inline with extra and max_num
-#
-class EpisodeMaxNum(Episode):
-    pass
-
 
 #
 # Generic inline with unique_together

tests/generic_inline_admin/tests.py

@@ -4,16 +4,16 @@ import warnings
 
 from django.contrib import admin
 from django.contrib.admin.sites import AdminSite
+from django.contrib.auth.models import User
 from django.contrib.contenttypes.admin import GenericTabularInline
 from django.contrib.contenttypes.forms import generic_inlineformset_factory
 from django.forms.formsets import DEFAULT_MAX_NUM
 from django.forms.models import ModelForm
-from django.test import TestCase, override_settings
+from django.test import TestCase, override_settings, RequestFactory
 
 # local test models
-from .admin import MediaInline, MediaPermanentInline
-from .models import (Episode, EpisodeExtra, EpisodeMaxNum, Media,
-    EpisodePermanent, Category)
+from .admin import MediaInline, MediaPermanentInline, site as admin_site
+from .models import Episode, Media, EpisodePermanent, Category
 
 
 @override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',),
@@ -136,6 +136,7 @@ class GenericInlineAdminParametersTest(TestCase):
 
     def setUp(self):
         self.client.login(username='super', password='secret')
+        self.factory = RequestFactory()
 
     def tearDown(self):
         self.client.logout()
@@ -165,9 +166,18 @@ class GenericInlineAdminParametersTest(TestCase):
         """
         With extra=0, there should be one form.
         """
-        e = self._create_object(EpisodeExtra)
-        response = self.client.get('/generic_inline_admin/admin/generic_inline_admin/episodeextra/%s/' % e.pk)
-        formset = response.context['inline_admin_formsets'][0].formset
+        class ExtraInline(GenericTabularInline):
+            model = Media
+            extra = 0
+
+        modeladmin = admin.ModelAdmin(Episode, admin_site)
+        modeladmin.inlines = [ExtraInline]
+
+        e = self._create_object(Episode)
+        request = self.factory.get('/generic_inline_admin/admin/generic_inline_admin/episode/%s/' % e.pk)
+        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(), 1)
         self.assertEqual(formset.initial_form_count(), 1)
 
@@ -175,12 +185,43 @@ class GenericInlineAdminParametersTest(TestCase):
         """
         With extra=5 and max_num=2, there should be only 2 forms.
         """
-        e = self._create_object(EpisodeMaxNum)
-        response = self.client.get('/generic_inline_admin/admin/generic_inline_admin/episodemaxnum/%s/' % e.pk)
-        formset = response.context['inline_admin_formsets'][0].formset
+        class MaxNumInline(GenericTabularInline):
+            model = Media
+            extra = 5
+            max_num = 2
+
+        modeladmin = admin.ModelAdmin(Episode, admin_site)
+        modeladmin.inlines = [MaxNumInline]
+
+        e = self._create_object(Episode)
+        request = self.factory.get('/generic_inline_admin/admin/generic_inline_admin/episode/%s/' % e.pk)
+        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(), 2)
         self.assertEqual(formset.initial_form_count(), 1)
 
+    def testMinNumParam(self):
+        """
+        With extra=3 and min_num=2, there should be six forms.
+        See #22628 - this will change when that's fixed.
+        """
+        class MinNumInline(GenericTabularInline):
+            model = Media
+            extra = 3
+            min_num = 2
+
+        modeladmin = admin.ModelAdmin(Episode, admin_site)
+        modeladmin.inlines = [MinNumInline]
+
+        e = self._create_object(Episode)
+        request = self.factory.get('/generic_inline_admin/admin/generic_inline_admin/episode/%s/' % e.pk)
+        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.initial_form_count(), 1)
+
 
 @override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
 class GenericInlineAdminWithUniqueTogetherTest(TestCase):

tests/model_formsets/tests.py

@@ -366,6 +366,33 @@ class ModelFormsetTest(TestCase):
             '<Author: Walt Whitman>',
         ])
 
+    def test_min_num(self):
+        # Test the behavior of min_num with model formsets. It should be
+        # added to extra.
+        qs = Author.objects.none()
+
+        AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=0)
+        formset = AuthorFormSet(queryset=qs)
+        self.assertEqual(len(formset.forms), 0)
+
+        AuthorFormSet = modelformset_factory(Author, fields="__all__", min_num=1, extra=0)
+        formset = AuthorFormSet(queryset=qs)
+        self.assertEqual(len(formset.forms), 1)
+
+        AuthorFormSet = modelformset_factory(Author, fields="__all__", min_num=1, extra=1)
+        formset = AuthorFormSet(queryset=qs)
+        self.assertEqual(len(formset.forms), 2)
+
+    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)
+
     def test_custom_save_method(self):
         class PoetForm(forms.ModelForm):
             def save(self, commit=True):

tests/modeladmin/tests.py

@@ -1444,6 +1444,33 @@ class MaxNumCheckTests(CheckTestCase):
         self.assertIsValid(ValidationTestModelAdmin, ValidationTestModel)
 
 
+class MinNumCheckTests(CheckTestCase):
+
+    def test_not_integer(self):
+        class ValidationTestInline(TabularInline):
+            model = ValidationTestInlineModel
+            min_num = "hello"
+
+        class ValidationTestModelAdmin(ModelAdmin):
+            inlines = [ValidationTestInline]
+
+        self.assertIsInvalid(
+            ValidationTestModelAdmin, ValidationTestModel,
+            "The value of 'min_num' must be an integer.",
+            'admin.E205',
+            invalid_obj=ValidationTestInline)
+
+    def test_valid_case(self):
+        class ValidationTestInline(TabularInline):
+            model = ValidationTestInlineModel
+            min_num = 2
+
+        class ValidationTestModelAdmin(ModelAdmin):
+            inlines = [ValidationTestInline]
+
+        self.assertIsValid(ValidationTestModelAdmin, ValidationTestModel)
+
+
 class FormsetCheckTests(CheckTestCase):
 
     def test_invalid_type(self):
@@ -1460,7 +1487,7 @@ class FormsetCheckTests(CheckTestCase):
         self.assertIsInvalid(
             ValidationTestModelAdmin, ValidationTestModel,
             "The value of 'formset' must inherit from 'BaseModelFormSet'.",
-            'admin.E205',
+            'admin.E206',
             invalid_obj=ValidationTestInline)
 
     def test_valid_case(self):