Fixed django#13023 - Removed ambiguity with regard to the max_num opt…

…ion of formsets and as a result of admin inlines. Thanks to Gabriel Hurley for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12872 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -225,6 +225,7 @@ answer newbie questions, and generally made Django that much better:
     John Huddleston <huddlej@wwu.edu>
     Rob Hudson <http://rob.cogit8.org/>
     Jason Huggins <http://www.jrandolph.com/blog/>
+    Gabriel Hurley <gabriel@strikeawe.com>
     Hyun Mi Ae
     Ibon <ibonso@gmail.com>
     Tom Insam

django/contrib/admin/media/js/inlines.js

@@ -32,8 +32,9 @@
 		};
 		var totalForms = $("#id_" + options.prefix + "-TOTAL_FORMS").attr("autocomplete", "off");
 		var maxForms = $("#id_" + options.prefix + "-MAX_NUM_FORMS").attr("autocomplete", "off");
-		// only show the add button if we are allowed to add more items
-		var showAddButton = ((maxForms.val() == 0) || ((maxForms.val()-totalForms.val()) > 0));
+		// only show the add button if we are allowed to add more items,
+        // note that max_num = None translates to a blank string.
+		var showAddButton = maxForms.val() == '' || (maxForms.val()-totalForms.val()) > 0;
 		$(this).each(function(i) {
 			$(this).not("." + options.emptyCssClass).addClass(options.formCssClass);
 		});
@@ -77,7 +78,7 @@
 				// Update number of total forms
 				$(totalForms).val(nextIndex + 1);
 				// Hide add button in case we've hit the max, except we want to add infinitely
-				if ((maxForms.val() != 0) && (maxForms.val() <= totalForms.val())) {
+				if ((maxForms.val() != '') && (maxForms.val() <= totalForms.val())) {
 					addButton.parent().hide();
 				}
 				// The delete button of each row triggers a bunch of other things
@@ -93,7 +94,7 @@
 					var forms = $("." + options.formCssClass);
 					$("#id_" + options.prefix + "-TOTAL_FORMS").val(forms.length);
 					// Show add button again once we drop below max
-					if ((maxForms.val() == 0) || (maxForms.val() >= forms.length)) {
+					if ((maxForms.val() == '') || (maxForms.val() >= forms.length)) {
 						addButton.parent().show();
 					}
 					// Also, update names and ids for all remaining form controls

django/contrib/admin/options.py

@@ -1179,7 +1179,7 @@ class InlineModelAdmin(BaseModelAdmin):
     fk_name = None
     formset = BaseInlineFormSet
     extra = 3
-    max_num = 0
+    max_num = None
     template = None
     verbose_name = None
     verbose_name_plural = None

django/contrib/admin/validation.py

@@ -170,11 +170,15 @@ def validate_inline(cls, parent, parent_model):
     fk = _get_foreign_key(parent_model, cls.model, fk_name=cls.fk_name, can_fail=True)
 
     # extra = 3
-    # max_num = 0
-    for attr in ('extra', 'max_num'):
-        if not isinstance(getattr(cls, attr), int):
-            raise ImproperlyConfigured("'%s.%s' should be a integer."
-                    % (cls.__name__, attr))
+    if not isinstance(getattr(cls, 'extra'), int):
+        raise ImproperlyConfigured("'%s.extra' should be a integer."
+                % cls.__name__)
+
+    # max_num = None
+    max_num = getattr(cls, 'max_num', None)
+    if max_num is not None and not isinstance(max_num, int):
+        raise ImproperlyConfigured("'%s.max_num' should be an integer or None (default)."
+                % cls.__name__)
 
     # formset
     if hasattr(cls, 'formset') and not issubclass(cls.formset, BaseModelFormSet):

django/contrib/contenttypes/generic.py

@@ -337,7 +337,7 @@ 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=0,
+                                  max_num=None,
                                   formfield_callback=lambda f: f.formfield()):
     """
     Returns an ``GenericInlineFormSet`` for the given kwargs.

django/forms/formsets.py

@@ -25,7 +25,7 @@ class ManagementForm(Form):
     def __init__(self, *args, **kwargs):
         self.base_fields[TOTAL_FORM_COUNT] = IntegerField(widget=HiddenInput)
         self.base_fields[INITIAL_FORM_COUNT] = IntegerField(widget=HiddenInput)
-        self.base_fields[MAX_NUM_FORM_COUNT] = IntegerField(widget=HiddenInput)
+        self.base_fields[MAX_NUM_FORM_COUNT] = IntegerField(required=False, widget=HiddenInput)
         super(ManagementForm, self).__init__(*args, **kwargs)
 
 class BaseFormSet(StrAndUnicode):
@@ -69,8 +69,13 @@ def total_form_count(self):
         if self.data or self.files:
             return self.management_form.cleaned_data[TOTAL_FORM_COUNT]
         else:
-            total_forms = self.initial_form_count() + self.extra
-            if total_forms > self.max_num > 0:
+            initial_forms = self.initial_form_count()
+            total_forms = initial_forms + 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:
+                total_forms = initial_forms
+            elif total_forms > self.max_num >= 0:
                 total_forms = self.max_num
         return total_forms
 
@@ -81,7 +86,7 @@ def initial_form_count(self):
         else:
             # Use the length of the inital data if it's there, 0 otherwise.
             initial_forms = self.initial and len(self.initial) or 0
-            if initial_forms > self.max_num > 0:
+            if initial_forms > self.max_num >= 0:
                 initial_forms = self.max_num
         return initial_forms
 
@@ -324,7 +329,7 @@ def as_table(self):
         return mark_safe(u'\n'.join([unicode(self.management_form), forms]))
 
 def formset_factory(form, formset=BaseFormSet, extra=1, can_order=False,
-                    can_delete=False, max_num=0):
+                    can_delete=False, max_num=None):
     """Return a FormSet for the given form class."""
     attrs = {'form': form, 'extra': extra,
              'can_order': can_order, 'can_delete': can_delete,

django/forms/models.py

@@ -448,10 +448,10 @@ def get_queryset(self):
             if not qs.ordered:
                 qs = qs.order_by(self.model._meta.pk.name)
 
-            if self.max_num > 0:
-                self._queryset = qs[:self.max_num]
-            else:
-                self._queryset = qs
+            # Removed queryset limiting here. As per discussion re: #13023
+            # on django-dev, max_num should not prevent existing
+            # related objects/inlines from being displayed.
+            self._queryset = qs
         return self._queryset
 
     def save_new(self, form, commit=True):
@@ -649,7 +649,7 @@ def pk_is_not_editable(pk):
 def modelformset_factory(model, form=ModelForm, formfield_callback=lambda f: f.formfield(),
                          formset=BaseModelFormSet,
                          extra=1, can_delete=False, can_order=False,
-                         max_num=0, fields=None, exclude=None):
+                         max_num=None, fields=None, exclude=None):
     """
     Returns a FormSet class for the given Django model class.
     """
@@ -799,7 +799,7 @@ def _get_foreign_key(parent_model, model, fk_name=None, can_fail=False):
 def 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=0,
+                          extra=3, can_order=False, can_delete=True, max_num=None,
                           formfield_callback=lambda f: f.formfield()):
     """
     Returns an ``InlineFormSet`` for the given kwargs.

docs/topics/forms/formsets.txt

@@ -71,7 +71,7 @@ Limiting the maximum number of forms
 ------------------------------------
 
 The ``max_num`` parameter to ``formset_factory`` gives you the ability to
-force the maximum number of forms the formset will display::
+limit the maximum number of empty forms the formset will display::
 
     >>> ArticleFormSet = formset_factory(ArticleForm, extra=2, max_num=1)
     >>> formset = ArticleFormset()
@@ -80,8 +80,20 @@ force the maximum number of forms the formset will display::
     <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" id="id_form-0-title" /></td></tr>
     <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" id="id_form-0-pub_date" /></td></tr>
 
-A ``max_num`` value of ``0`` (the default) puts no limit on the number forms
-displayed.
+.. versionchanged:: 1.2
+
+If the value of ``max_num`` is geater than the number of existing related
+objects, up to ``extra`` additional blank forms will be added to the formset,
+so long as the total number of forms does not exceed ``max_num``.
+
+A ``max_num`` value of ``None`` (the default) puts no limit on the number of
+forms displayed. Please note that the default value of ``max_num`` was changed
+from ``0`` to ``None`` in version 1.2 to allow ``0`` as a valid value.
+
+.. versionadded:: 1.2
+
+The dynamic "Add Another" link in the Django admin will not appear if
+``max_num`` is less than the number of currently displayed forms.
 
 Formset validation
 ------------------
@@ -102,7 +114,7 @@ provide an invalid article::
     >>> data = {
     ...     'form-TOTAL_FORMS': u'2',
     ...     'form-INITIAL_FORMS': u'0',
-    ...     'form-MAX_NUM_FORMS': u'0',
+    ...     'form-MAX_NUM_FORMS': u'',
     ...     'form-0-title': u'Test',
     ...     'form-0-pub_date': u'16 June 1904',
     ...     'form-1-title': u'Test',
@@ -190,7 +202,7 @@ is where you define your own validation that works at the formset level::
     >>> data = {
     ...     'form-TOTAL_FORMS': u'2',
     ...     'form-INITIAL_FORMS': u'0',
-    ...     'form-MAX_NUM_FORMS': u'0',
+    ...     'form-MAX_NUM_FORMS': u'',
     ...     'form-0-title': u'Test',
     ...     'form-0-pub_date': u'16 June 1904',
     ...     'form-1-title': u'Test',
@@ -249,7 +261,7 @@ happen when the user changes these values::
     >>> data = {
     ...     'form-TOTAL_FORMS': u'3',
     ...     'form-INITIAL_FORMS': u'2',
-    ...     'form-MAX_NUM_FORMS': u'0',
+    ...     'form-MAX_NUM_FORMS': u'',
     ...     'form-0-title': u'Article #1',
     ...     'form-0-pub_date': u'2008-05-10',
     ...     'form-0-ORDER': u'2',
@@ -287,7 +299,7 @@ Lets create a formset with the ability to delete::
     ... ])
     >>> for form in formset.forms:
     ....    print form.as_table()
-    <input type="hidden" name="form-TOTAL_FORMS" value="3" id="id_form-TOTAL_FORMS" /><input type="hidden" name="form-INITIAL_FORMS" value="2" id="id_form-INITIAL_FORMS" /><input type="hidden" name="form-MAX_NUM_FORMS" value="0" id="id_form-MAX_NUM_FORMS" />
+    <input type="hidden" name="form-TOTAL_FORMS" value="3" id="id_form-TOTAL_FORMS" /><input type="hidden" name="form-INITIAL_FORMS" value="2" id="id_form-INITIAL_FORMS" /><input type="hidden" name="form-MAX_NUM_FORMS" id="id_form-MAX_NUM_FORMS" />
     <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" value="Article #1" id="id_form-0-title" /></td></tr>
     <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" value="2008-05-10" id="id_form-0-pub_date" /></td></tr>
     <tr><th><label for="id_form-0-DELETE">Delete:</label></th><td><input type="checkbox" name="form-0-DELETE" id="id_form-0-DELETE" /></td></tr>
@@ -305,7 +317,7 @@ delete fields you can access them with ``deleted_forms``::
     >>> data = {
     ...     'form-TOTAL_FORMS': u'3',
     ...     'form-INITIAL_FORMS': u'2',
-    ...     'form-MAX_NUM_FORMS': u'0',
+    ...     'form-MAX_NUM_FORMS': u'',
     ...     'form-0-title': u'Article #1',
     ...     'form-0-pub_date': u'2008-05-10',
     ...     'form-0-DELETE': u'on',

docs/topics/forms/modelforms.txt

@@ -369,7 +369,7 @@ Overriding the default field types or widgets
 The default field types, as described in the `Field types`_ table above, are
 sensible defaults. If you have a ``DateField`` in your model, chances are you'd
 want that to be represented as a ``DateField`` in your form. But
-``ModelForm`` gives you the flexibility of changing the form field type and 
+``ModelForm`` gives you the flexibility of changing the form field type and
 widget for a given model field.
 
 To specify a custom widget for a field, use the ``widgets`` attribute of the
@@ -401,7 +401,7 @@ field, you could do the following::
 
     class ArticleForm(ModelForm):
         pub_date = MyDateFormField()
-    
+
         class Meta:
             model = Article
 
@@ -557,7 +557,7 @@ with the ``Author`` model. It works just like a regular formset::
 
     >>> formset = AuthorFormSet()
     >>> print formset
-    <input type="hidden" name="form-TOTAL_FORMS" value="1" id="id_form-TOTAL_FORMS" /><input type="hidden" name="form-INITIAL_FORMS" value="0" id="id_form-INITIAL_FORMS" /><input type="hidden" name="form-MAX_NUM_FORMS" value="0" id="id_form-MAX_NUM_FORMS" />
+    <input type="hidden" name="form-TOTAL_FORMS" value="1" id="id_form-TOTAL_FORMS" /><input type="hidden" name="form-INITIAL_FORMS" value="0" id="id_form-INITIAL_FORMS" /><input type="hidden" name="form-MAX_NUM_FORMS" id="id_form-MAX_NUM_FORMS" />
     <tr><th><label for="id_form-0-name">Name:</label></th><td><input id="id_form-0-name" type="text" name="form-0-name" maxlength="100" /></td></tr>
     <tr><th><label for="id_form-0-title">Title:</label></th><td><select name="form-0-title" id="id_form-0-title">
     <option value="" selected="selected">---------</option>
@@ -653,22 +653,24 @@ are saved properly.
 Limiting the number of editable objects
 ---------------------------------------
 
+.. versionchanged:: 1.2
+
 As with regular formsets, you can use the ``max_num`` parameter to
-``modelformset_factory`` to limit the number of forms displayed. With
-model formsets, this property limits the query to select only the maximum
-number of objects needed::
+``modelformset_factory`` to limit the number of extra forms displayed.
+
+``max_num`` does not prevent existing objects from being displayed::
 
     >>> Author.objects.order_by('name')
     [<Author: Charles Baudelaire>, <Author: Paul Verlaine>, <Author: Walt Whitman>]
 
-    >>> AuthorFormSet = modelformset_factory(Author, max_num=2, extra=1)
+    >>> AuthorFormSet = modelformset_factory(Author, max_num=1)
     >>> formset = AuthorFormSet(queryset=Author.objects.order_by('name'))
-    >>> formset.initial
-    [{'id': 1, 'name': u'Charles Baudelaire'}, {'id': 3, 'name': u'Paul Verlaine'}]
+    >>> [x.name for x in formset.get_queryset()]
+    [u'Charles Baudelaire', u'Paul Verlaine', u'Walt Whitman']
 
-If the value of ``max_num`` is higher than the number of objects returned, up to
-``extra`` additional blank forms will be added to the formset, so long as the
-total number of forms does not exceed ``max_num``::
+If the value of ``max_num`` is geater than the number of existing related
+objects, up to ``extra`` additional blank forms will be added to the formset,
+so long as the total number of forms does not exceed ``max_num``::
 
     >>> AuthorFormSet = modelformset_factory(Author, max_num=4, extra=2)
     >>> formset = AuthorFormSet(queryset=Author.objects.order_by('name'))
@@ -679,6 +681,11 @@ total number of forms does not exceed ``max_num``::
     <tr><th><label for="id_form-2-name">Name:</label></th><td><input id="id_form-2-name" type="text" name="form-2-name" value="Walt Whitman" maxlength="100" /><input type="hidden" name="form-2-id" value="2" id="id_form-2-id" /></td></tr>
     <tr><th><label for="id_form-3-name">Name:</label></th><td><input id="id_form-3-name" type="text" name="form-3-name" maxlength="100" /><input type="hidden" name="form-3-id" id="id_form-3-id" /></td></tr>
 
+.. versionchanged:: 1.2
+
+A ``max_num`` value of ``None`` (the default) puts no limit on the number of
+forms displayed.
+
 Using a model formset in a view
 -------------------------------