Fixed #7369: fixed a corner-case involving select_related() following non-null... (31d9dc07) · Commits · Dom Sekotill / django

django/db/models/sql/query.py

+12 −4

Original line number	Diff line number	Diff line
		@@ -851,7 +851,7 @@ class Query(object):
		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 @@ class Query(object):
		(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 @@ class Query(object):
		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 @@ class Query(object):
		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):

tests/regressiontests/null_fk/init.py

0 → 100644

+0 −0

Empty file added.

tests/regressiontests/null_fk/models.py

0 → 100644

+55 −0

Original line number	Diff line number	Diff line
		"""
		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)]

		"""}