Fixed #7512 -- Fixed an oversight when I first fixed ordering on nullable

foreign keys (r7761). Thanks to George Vilches for the test case here.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8783 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/query.py

@@ -658,8 +658,9 @@ class Query(object):
             self.ref_alias(alias)
 
         # Must use left outer joins for nullable fields.
+        must_promote = False
         for join in joins:
-            self.promote_alias(join)
+            must_promote = self.promote_alias(join, must_promote)
 
         # If we get to this point and the field is a relation to another model,
         # append the default ordering for that model.

tests/regressiontests/null_fk_ordering/models.py

@@ -0,0 +1,95 @@
+"""
+Regression tests for proper working of ForeignKey(null=True). Tests these bugs:
+
+    * #7512: including a nullable foreign key reference in Meta ordering has un
+xpected results
+
+"""
+
+from django.db import models
+
+# The first two models represent a very simple null FK ordering case.
+class Author(models.Model):
+    name = models.CharField(max_length=150)
+
+class Article(models.Model):
+    title = models.CharField(max_length=150)
+    author = models.ForeignKey(Author, null=True)
+
+    def __unicode__(self):
+        return u'Article titled: %s' % (self.title, )
+
+    class Meta:
+        ordering = ['author__name', ]
+
+
+# These following 4 models represent a far more complex ordering case.
+class SystemInfo(models.Model):
+    system_name = models.CharField(max_length=32)
+
+class Forum(models.Model):
+    system_info = models.ForeignKey(SystemInfo)
+    forum_name = models.CharField(max_length=32)
+
+class Post(models.Model):
+    forum = models.ForeignKey(Forum, null=True)
+    title = models.CharField(max_length=32)
+
+    def __unicode__(self):
+        return self.title
+
+class Comment(models.Model):
+    post = models.ForeignKey(Post, null=True)
+    comment_text = models.CharField(max_length=250)
+
+    class Meta:
+        ordering = ['post__forum__system_info__system_name', 'comment_text']
+
+    def __unicode__(self):
+        return self.comment_text
+
+class Comment(models.Model):
+    post = models.ForeignKey(Post, null=True)
+    comment_text = models.CharField(max_length=250)
+
+    class Meta:
+        ordering = ['post__forum__system_info__system_name', 'comment_text']
+
+    def __unicode__(self):
+        return self.comment_text
+
+__test__ = {'API_TESTS': """
+# Regression test for #7512 -- ordering across nullable Foreign Keys shouldn't
+# exclude results
+>>> author_1 = Author.objects.create(name='Tom Jones')
+>>> author_2 = Author.objects.create(name='Bob Smith')
+>>> article_1 = Article.objects.create(title='No author on this article')
+>>> article_2 = Article.objects.create(author=author_1, title='This article written by Tom Jones')
+>>> article_3 = Article.objects.create(author=author_2, title='This article written by Bob Smith')
+
+# We can't compare results directly (since different databases sort NULLs to
+# different ends of the ordering), but we can check that all results are
+# returned.
+>>> len(list(Article.objects.all())) == 3
+True
+
+>>> s = SystemInfo.objects.create(system_name='System Info')
+>>> f = Forum.objects.create(system_info=s, forum_name='First forum')
+>>> p = Post.objects.create(forum=f, title='First Post')
+>>> c1 = Comment.objects.create(post=p, comment_text='My first comment')
+>>> c2 = Comment.objects.create(comment_text='My second comment')
+>>> s2 = SystemInfo.objects.create(system_name='More System Info')
+>>> f2 = Forum.objects.create(system_info=s2, forum_name='Second forum')
+>>> p2 = Post.objects.create(forum=f2, title='Second Post')
+>>> c3 = Comment.objects.create(comment_text='Another first comment')
+>>> c4 = Comment.objects.create(post=p2, comment_text='Another second comment')
+
+# We have to test this carefully. Some databases sort NULL values before
+# everything else, some sort them afterwards. So we extract the ordered list
+# and check the length. Before the fix, this list was too short (some values
+# were omitted).
+>>> len(list(Comment.objects.all())) == 4
+True
+
+"""
+}