Fixed #1661 -- Added logic for string-form model references in the 'to' argument of OneToOneFields. Includes regression test.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3197 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/related.py

@@ -515,8 +515,13 @@ class ForeignKey(RelatedField, Field):
 
 class OneToOneField(RelatedField, IntegerField):
     def __init__(self, to, to_field=None, **kwargs):
+        try:
+            to_name = to._meta.object_name.lower()
+        except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
+            assert isinstance(to, basestring), "OneToOneField(%r) is invalid. First parameter to OneToOneField must be either a model, a model name, or the string %r" % (to, RECURSIVE_RELATIONSHIP_CONSTANT)
+        else:
+            to_field = to_field or to._meta.pk.name
         kwargs['verbose_name'] = kwargs.get('verbose_name', '')
-        to_field = to_field or to._meta.pk.name
 
         if kwargs.has_key('edit_inline_type'):
             import warnings

tests/regressiontests/string_lookup/models.py

@@ -21,9 +21,22 @@ class Whiz(models.Model):
     def __str__(self):
         return "Whiz %s" % self.name
 
+class Child(models.Model):
+    parent = models.OneToOneField('Base')
+    name = models.CharField(maxlength = 50)
+
+    def __str__(self):
+        return "Child %s" % self.name
+    
+class Base(models.Model):
+    name = models.CharField(maxlength = 50)
+
+    def __str__(self):
+        return "Base %s" % self.name
+
 API_TESTS = """
-# Regression test for #1662: Check that string form referencing of models works, both as
-# pre and post reference
+# Regression test for #1661 and #1662: Check that string form referencing of models works, 
+# both as pre and post reference, on all RelatedField types.
 
 >>> f1 = Foo(name="Foo1")
 >>> f1.save()
@@ -45,4 +58,12 @@ API_TESTS = """
 >>> b1.back
 <Foo: Foo Foo1>
 
+>>> base1 = Base(name="Base1")
+>>> base1.save()
+
+>>> child1 = Child(name="Child1", parent=base1)
+>>> child1.save()
+
+>>> child1.parent
+<Base: Base Base1>
 """