Fixed #7885 -- Prevent duplicates in fields and fieldsets declarations. Thanks...

try:

    set

except NameError:

    from sets import Set as set   # Python 2.3 fallback

from django.core.exceptions import ImproperlyConfigured

from django.db import models

            _check_form_field_existsw('fields', field)

        if cls.fieldsets:

            raise ImproperlyConfigured('Both fieldsets and fields are specified in %s.' % cls.__name__)

        if len(cls.fields) > len(set(cls.fields)):

            raise ImproperlyConfigured('There are duplicate field(s) in %s.fields' % cls.__name__)

    # fieldsets

    if cls.fieldsets: # default value is None

                raise ImproperlyConfigured("`fields` key is required in "

                        "%s.fieldsets[%d][1] field options dict."

                        % (cls.__name__, idx))

        for field in flatten_fieldsets(cls.fieldsets):

        flattened_fieldsets = flatten_fieldsets(cls.fieldsets)

        if len(flattened_fieldsets) > len(set(flattened_fieldsets)):

            raise ImproperlyConfigured('There are duplicate field(s) in %s.fieldsets' % cls.__name__)

        for field in flattened_fieldsets:

            _check_form_field_existsw("fieldsets[%d][1]['fields']" % idx, field)

    # form

...

ImproperlyConfigured: Both fieldsets and fields are specified in ValidationTestModelAdmin.

>>> class ValidationTestModelAdmin(ModelAdmin): 

...     fieldsets = [(None, {'fields': ['name', 'name']})] 

>>> validate(ValidationTestModelAdmin, ValidationTestModel) 

Traceback (most recent call last): 

... 

ImproperlyConfigured: There are duplicate field(s) in ValidationTestModelAdmin.fieldsets

>>> class ValidationTestModelAdmin(ModelAdmin):

...     fields = ["name", "name"]

>>> validate(ValidationTestModelAdmin, ValidationTestModel)

Traceback (most recent call last):

...

ImproperlyConfigured: There are duplicate field(s) in ValidationTestModelAdmin.fields

# form

>>> class FakeForm(object):