Fixed #494 -- Added ability to specify classes on admin inline fieldsets.

This includes the ability to collapse inlines by specifying a class named
'collapse'.

django/contrib/admin/helpers.py

@@ -235,6 +235,7 @@ class InlineAdminFormSet(object):
         if prepopulated_fields is None:
             prepopulated_fields = {}
         self.prepopulated_fields = prepopulated_fields
+        self.classes = ' '.join(inline.classes) if inline.classes else ''
 
     def __iter__(self):
         for form, original in zip(self.formset.initial_forms, self.formset.get_queryset()):

django/contrib/admin/options.py

@@ -1800,6 +1800,7 @@ class InlineModelAdmin(BaseModelAdmin):
     can_delete = True
     show_change_link = False
     checks_class = InlineModelAdminChecks
+    classes = None
 
     def __init__(self, parent_model, admin_site):
         self.admin_site = admin_site
@@ -1819,6 +1820,8 @@ class InlineModelAdmin(BaseModelAdmin):
               'inlines%s.js' % extra]
         if self.filter_vertical or self.filter_horizontal:
             js.extend(['SelectBox.js', 'SelectFilter2.js'])
+        if self.classes and 'collapse' in self.classes:
+            js.append('collapse%s.js' % extra)
         return forms.Media(js=['admin/js/%s' % url for url in js])
 
     def get_extra(self, request, obj=None, **kwargs):

django/contrib/admin/templates/admin/edit_inline/stacked.html

@@ -3,6 +3,7 @@
      id="{{ inline_admin_formset.formset.prefix }}-group"
      data-inline-type="stacked"
      data-inline-formset="{{ inline_admin_formset.inline_formset_data }}">
+<fieldset class="module {{ inline_admin_formset.classes }}">
   <h2>{{ inline_admin_formset.opts.verbose_name_plural|capfirst }}</h2>
 {{ inline_admin_formset.formset.management_form }}
 {{ inline_admin_formset.formset.non_form_errors }}
@@ -20,4 +21,5 @@
   {% if inline_admin_form.needs_explicit_pk_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
   {{ inline_admin_form.fk_field.field }}
 </div>{% endfor %}
+</fieldset>
 </div>

django/contrib/admin/templates/admin/edit_inline/tabular.html

@@ -4,7 +4,7 @@
      data-inline-formset="{{ inline_admin_formset.inline_formset_data }}">
   <div class="tabular inline-related {% if forloop.last %}last-related{% endif %}">
 {{ inline_admin_formset.formset.management_form }}
-<fieldset class="module">
+<fieldset class="module {{ inline_admin_formset.classes }}">
    <h2>{{ inline_admin_formset.opts.verbose_name_plural|capfirst }}</h2>
    {{ inline_admin_formset.formset.non_form_errors }}
    <table>