[1.0.X] Fixed #9649 -- Better error handling in model creation.

Previously, you could explicitly assign None to a non-null ForeignKey
(or other) field when creating the model (Child(parent=None), etc). We
now throw an exception when you do that, which matches the behaviour
when you assign None to the attribute after creation.

Thanks to ales.zoulek@gmail.com and ondrej.kohout@gmail.com for some
analysis of this problem.

Backport of r9983 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9984 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 12 insertions, 1 deletions

diff --git a/tests/regressiontests/many_to_one_regress/models.py b/tests/regressiontests/many_to_one_regress/models.py
index 2039bd5ddf..3f35bef62c 100644
--- a/tests/regressiontests/many_to_one_regress/models.py
+++ b/tests/regressiontests/many_to_one_regress/models.py
@@ -1,5 +1,5 @@
 """
-Regression tests for a few FK bugs: #1578, #6886
+Regression tests for a few ForeignKey bugs.
 """
 
 from django.db import models
@@ -106,6 +106,17 @@ Traceback (most recent call last):
     ...
 ValueError: Cannot assign "<First: First object>": "Child.parent" must be a "Parent" instance.
 
+# Nor can you explicitly assign None to Child.parent during object creation
+# (regression for #9649).
+>>> Child(name='xyzzy', parent=None)
+Traceback (most recent call last):
+    ...
+ValueError: Cannot assign None: "Child.parent" does not allow null values.
+>>> Child.objects.create(name='xyzzy', parent=None)
+Traceback (most recent call last):
+    ...
+ValueError: Cannot assign None: "Child.parent" does not allow null values.
+
 # Creation using keyword argument should cache the related object.
 >>> p = Parent.objects.get(name="Parent")
 >>> c = Child(parent=p)