[1.0.X] Fixed #9188 -- Fixed a case where we were generating syntacti…

…cally invalid SQL in some exclude() queries.

Backport of r9588 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9589 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/query.py

@@ -1695,7 +1695,6 @@ def set_start(self, start):
         alias = self.get_initial_alias()
         field, col, opts, joins, last, extra = self.setup_joins(
                 start.split(LOOKUP_SEP), opts, alias, False)
-        self.unref_alias(alias)
         alias = joins[last[-1]]
         self.select = [(alias, self.alias_map[alias][RHS_JOIN_COL])]
         self.select_fields = [field]

tests/regressiontests/queries/models.py

@@ -227,6 +227,17 @@ class ReservedName(models.Model):
     def __unicode__(self):
         return self.name
 
+# A simpler shared-foreign-key setup that can expose some problems.
+class SharedConnection(models.Model):
+    data = models.CharField(max_length=10)
+
+class PointerA(models.Model):
+    connection = models.ForeignKey(SharedConnection)
+
+class PointerB(models.Model):
+    connection = models.ForeignKey(SharedConnection)
+
+
 __test__ = {'API_TESTS':"""
 >>> t1 = Tag.objects.create(name='t1')
 >>> t2 = Tag.objects.create(name='t2', parent=t1)
@@ -986,6 +997,14 @@ def __unicode__(self):
 >>> qs = Author.objects.order_by().order_by('name')
 >>> 'ORDER BY' in qs.query.as_sql()[0]
 True
+
+Bug #9188 -- incorrect SQL was being generated for certain types of
+exclude() queries that crossed multi-valued relations.
+
+>>> PointerA.objects.filter(connection__pointerb__id=1)
+[]
+>>> PointerA.objects.exclude(connection__pointerb__id=1)
+[]
 """}
 
 # In Python 2.3 and the Python 2.6 beta releases, exceptions raised in __len__