Fixed #6886: Tightened up ForeignKey and OneToOne field assignment. Specifically:

  * Raise a ValueError if you try to assign the wrong type of object.
  * Raise a ValueError if you try to assign None to a field not specified with null=True.
  * Cache the set value at set time instead of just at lookup time.

This is a slightly backwards-incompatible change; see BackwardsIncompatibleChanges for more details.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7574 bcc190cf-cafb-0310-a4f2-bffc1f526a37

2 files changed, 82 insertions, 2 deletions

diff --git a/tests/regressiontests/many_to_one_regress/models.py b/tests/regressiontests/many_to_one_regress/models.py
index 57bbcd8489..4e49df1555 100644
--- a/tests/regressiontests/many_to_one_regress/models.py
+++ b/tests/regressiontests/many_to_one_regress/models.py
@@ -1,3 +1,7 @@
+"""
+Regression tests for a few FK bugs: #1578, #6886
+"""
+
 from django.db import models
 
 # If ticket #1578 ever slips back in, these models will not be able to be
@@ -25,10 +29,48 @@ class Child(models.Model):
 
 
 __test__ = {'API_TESTS':"""
->>> Third.AddManipulator().save(dict(id='3', name='An example', another=None)) 
+>>> Third.objects.create(id='3', name='An example')
 <Third: Third object>
 >>> parent = Parent(name = 'fred')
 >>> parent.save()
->>> Child.AddManipulator().save(dict(name='bam-bam', parent=parent.id))
+>>> Child.objects.create(name='bam-bam', parent=parent)
 <Child: Child object>
+
+#
+# Tests of ForeignKey assignment and the related-object cache (see #6886)
+#
+>>> p = Parent.objects.create(name="Parent")
+>>> c = Child.objects.create(name="Child", parent=p)
+
+# Look up the object again so that we get a "fresh" object
+>>> c = Child.objects.get(name="Child")
+>>> p = c.parent
+
+# Accessing the related object again returns the exactly same object
+>>> c.parent is p
+True
+
+# But if we kill the cache, we get a new object
+>>> del c._parent_cache
+>>> c.parent is p
+False
+
+# Assigning a new object results in that object getting cached immediately
+>>> p2 = Parent.objects.create(name="Parent 2")
+>>> c.parent = p2
+>>> c.parent is p2
+True
+
+# Assigning None fails: Child.parent is null=False
+>>> c.parent = None
+Traceback (most recent call last):
+    ...
+ValueError: Cannot assign None: "Child.parent" does not allow null values.
+
+# You also can't assign an object of the wrong type here
+>>> c.parent = First(id=1, second=1)
+Traceback (most recent call last):
+    ...
+ValueError: Cannot assign "<First: First object>": "Child.parent" must be a "Parent" instance.
+
 """}
diff --git a/tests/regressiontests/one_to_one_regress/models.py b/tests/regressiontests/one_to_one_regress/models.py
index c68fdfc780..99022882f2 100644
--- a/tests/regressiontests/one_to_one_regress/models.py
+++ b/tests/regressiontests/one_to_one_regress/models.py
@@ -50,4 +50,42 @@ __test__ = {'API_TESTS':"""
 <Restaurant: Demon Dogs the restaurant>
 >>> p1.bar
 <Bar: Demon Dogs the bar>
+
+#
+# Regression test for #6886 (the related-object cache)
+# 
+
+# Look up the objects again so that we get "fresh" objects
+>>> p = Place.objects.get(name="Demon Dogs")
+>>> r = p.restaurant
+
+# Accessing the related object again returns the exactly same object
+>>> p.restaurant is r
+True
+
+# But if we kill the cache, we get a new object
+>>> del p._restaurant_cache
+>>> p.restaurant is r
+False
+
+# Reassigning the Restaurant object results in an immediate cache update
+# We can't use a new Restaurant because that'll violate one-to-one, but
+# with a new *instance* the is test below will fail if #6886 regresses.
+>>> r2 = Restaurant.objects.get(pk=r.pk)
+>>> p.restaurant = r2
+>>> p.restaurant is r2
+True
+
+# Assigning None fails: Place.restaurant is null=False
+>>> p.restaurant = None
+Traceback (most recent call last):
+    ...
+ValueError: Cannot assign None: "Place.restaurant" does not allow null values.
+
+# You also can't assign an object of the wrong type here
+>>> p.restaurant = p
+Traceback (most recent call last):
+    ...
+ValueError: Cannot assign "<Place: Demon Dogs the place>": "Place.restaurant" must be a "Restaurant" instance.
+
 """}