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Fixed #7369: fixed a corner-case involving select_related() following…

… non-null FKs after null ones. Thanks, George Vilches

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7597 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit 31d9dc07aa6d8c424bc84821d529cf3356e04a71 1 parent 8398ea6
Jacob Kaplan-Moss jacobian authored
16 django/db/models/sql/query.py
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@@ -851,7 +851,7 @@ def join(self, connection, always_create=False, exclusions=(),
return alias
def fill_related_selections(self, opts=None, root_alias=None, cur_depth=1,
- used=None, requested=None, restricted=None):
+ used=None, requested=None, restricted=None, nullable=None):
"""
Fill in the information needed for a select_related query. The current
depth is measured as the number of connections away from the root model
@@ -883,6 +883,10 @@ def fill_related_selections(self, opts=None, root_alias=None, cur_depth=1,
(not restricted and f.null) or f.rel.parent_link):
continue
table = f.rel.to._meta.db_table
+ if nullable or f.null:
+ promote = True
+ else:
+ promote = False
if model:
int_opts = opts
alias = root_alias
@@ -891,12 +895,12 @@ def fill_related_selections(self, opts=None, root_alias=None, cur_depth=1,
int_opts = int_model._meta
alias = self.join((alias, int_opts.db_table, lhs_col,
int_opts.pk.column), exclusions=used,
- promote=f.null)
+ promote=promote)
else:
alias = root_alias
alias = self.join((alias, table, f.column,
f.rel.get_related_field().column), exclusions=used,
- promote=f.null)
+ promote=promote)
used.add(alias)
self.related_select_cols.extend([(alias, f2.column)
for f2 in f.rel.to._meta.fields])
@@ -905,8 +909,12 @@ def fill_related_selections(self, opts=None, root_alias=None, cur_depth=1,
next = requested.get(f.name, {})
else:
next = False
+ if f.null is not None:
+ new_nullable = f.null
+ else:
+ new_nullable = None
self.fill_related_selections(f.rel.to._meta, alias, cur_depth + 1,
- used, next, restricted)
+ used, next, restricted, new_nullable)
def add_filter(self, filter_expr, connector=AND, negate=False, trim=False,
can_reuse=None):
0  tests/regressiontests/null_fk/__init__.py
View
No changes.
55 tests/regressiontests/null_fk/models.py
View
@@ -0,0 +1,55 @@
+"""
+Regression tests for proper working of ForeignKey(null=True). Tests these bugs:
+
+ * #7369: FK non-null after null relationship on select_related() generates an invalid query
+
+"""
+
+from django.db import models
+
+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)
+
+ def __unicode__(self):
+ return self.comment_text
+
+__test__ = {'API_TESTS':"""
+
+>>> s = SystemInfo.objects.create(system_name='First forum')
+>>> 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')
+
+# Starting from comment, make sure that a .select_related(...) with a specified
+# set of fields will properly LEFT JOIN multiple levels of NULLs (and the things
+# that come after the NULLs, or else data that should exist won't).
+>>> c = Comment.objects.select_related().get(id=1)
+>>> c.post
+<Post: First Post>
+>>> c = Comment.objects.select_related().get(id=2)
+>>> print c.post
+None
+
+>>> comments = Comment.objects.select_related('post__forum__system_info').all()
+>>> [(c.id, c.post.id) for c in comments]
+[(1, 1), (2, None)]
+>>> [(c.comment_text, c.post.title) for c in comments]
+[(u'My first comment', u'First Post'), (u'My second comment', None)]
+
+"""}
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