Fixed #13138: Ensure required=False on a model form field overrides

blank=False on the underlying model field during model form clean, 
in order to maintain backward compatibility. Thanks to saxon75 for 
the report.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@12802 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/modeltests/model_forms/mforms.py

@@ -1,6 +1,7 @@
+from django import forms
 from django.forms import ModelForm
 
-from models import Product, Price, Book, DerivedBook, ExplicitPK, Post, DerivedPost
+from models import Product, Price, Book, DerivedBook, ExplicitPK, Post, DerivedPost, Writer
 
 class ProductForm(ModelForm):
     class Meta:
@@ -30,3 +31,9 @@ class PostForm(ModelForm):
 class DerivedPostForm(ModelForm):
     class Meta:
         model = DerivedPost
+
+class CustomWriterForm(ModelForm):
+   name = forms.CharField(required=False)
+
+   class Meta:
+       model = Writer

tests/modeltests/model_forms/tests.py

@@ -2,7 +2,8 @@ import datetime
 from django.test import TestCase
 from django import forms
 from models import Category, Writer, Book, DerivedBook, Post
-from mforms import ProductForm, PriceForm, BookForm, DerivedBookForm, ExplicitPKForm, PostForm, DerivedPostForm
+from mforms import (ProductForm, PriceForm, BookForm, DerivedBookForm, 
+                   ExplicitPKForm, PostForm, DerivedPostForm, CustomWriterForm)
 
 
 class IncompleteCategoryFormWithFields(forms.ModelForm):
@@ -37,6 +38,10 @@ class ValidationTest(TestCase):
         form = IncompleteCategoryFormWithExclude(data={'name': 'some name', 'slug': 'some-slug'})
         assert form.is_valid()
 
+    def test_notrequired_overrides_notblank(self):
+        form = CustomWriterForm({})
+        assert form.is_valid()
+
 # unique/unique_together validation
 class UniqueTest(TestCase):
     def setUp(self):