Corrected a regression in validation of admin fieldsets with nested definitions from r11744. Thanks to Davor Lučić for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11752 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/admin/validation.py

@@ -219,7 +219,12 @@ def validate_base(cls, model):
                 raise ImproperlyConfigured("'fields' key is required in "
                         "%s.fieldsets[%d][1] field options dict."
                         % (cls.__name__, idx))
-            for field in fieldset[1]['fields']:
+            for fields in fieldset[1]['fields']:
+                # The entry in fields might be a tuple. If it is a standalone
+                # field, make it into a tuple to make processing easier.
+                if type(fields) != tuple:
+                    fields = (fields,)
+                for field in fields:
                     check_formfield(cls, model, opts, "fieldsets[%d][1]['fields']" % idx, field)
                     try:
                         f = opts.get_field(field)

tests/regressiontests/admin_validation/models.py

@@ -32,6 +32,8 @@ class Author(models.Model):
 
 class Book(models.Model):
     name = models.CharField(max_length=100)
+    subtitle = models.CharField(max_length=100)
+    price = models.FloatField()
     authors = models.ManyToManyField(Author, through='AuthorsBooks')
 
 
@@ -131,6 +133,13 @@ Traceback (most recent call last):
    ...
 ImproperlyConfigured: 'FieldsetBookAdmin.fieldsets[1][1]['fields']' can't include the ManyToManyField field 'authors' because 'authors' manually specifies a 'through' model.
 
+>>> class NestedFieldsetAdmin(admin.ModelAdmin):
+...    fieldsets = (
+...        ('Main', {'fields': ('price', ('name', 'subtitle'))}),
+...    )
+
+>>> validate(NestedFieldsetAdmin, Book)
+
 # Regression test for #12209 -- If the explicitly provided through model
 # is specified as a string, the admin should still be able use
 # Model.m2m_field.through