Fixed handling of multiple fields in a model pointing to the same related model.

Thanks to ElliotM, mk and oyvind for some excellent test cases for this. Fixed #7110, #7125.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7778 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/many_to_one_regress/models.py

@@ -28,6 +28,24 @@ class Child(models.Model):
     parent = models.ForeignKey(Parent)
 
 
+# Multiple paths to the same model (#7110, #7125)
+class Category(models.Model):
+    name = models.CharField(max_length=20)
+
+    def __unicode__(self):
+        return self.name
+
+class Record(models.Model):
+    category = models.ForeignKey(Category)
+
+class Relation(models.Model):
+    left = models.ForeignKey(Record, related_name='left_set')
+    right = models.ForeignKey(Record, related_name='right_set')
+
+    def __unicode__(self):
+        return u"%s - %s" % (self.left.category.name, self.right.category.name)
+
+
 __test__ = {'API_TESTS':"""
 >>> Third.objects.create(id='3', name='An example')
 <Third: Third object>
@@ -73,4 +91,26 @@ Traceback (most recent call last):
     ...
 ValueError: Cannot assign "<First: First object>": "Child.parent" must be a "Parent" instance.
 
+# Test of multiple ForeignKeys to the same model (bug #7125)
+
+>>> c1 = Category.objects.create(name='First')
+>>> c2 = Category.objects.create(name='Second')
+>>> c3 = Category.objects.create(name='Third')
+>>> r1 = Record.objects.create(category=c1)
+>>> r2 = Record.objects.create(category=c1)
+>>> r3 = Record.objects.create(category=c2)
+>>> r4 = Record.objects.create(category=c2)
+>>> r5 = Record.objects.create(category=c3)
+>>> r = Relation.objects.create(left=r1, right=r2)
+>>> r = Relation.objects.create(left=r3, right=r4)
+>>> r = Relation.objects.create(left=r1, right=r3)
+>>> r = Relation.objects.create(left=r5, right=r2)
+>>> r = Relation.objects.create(left=r3, right=r2)
+
+>>> Relation.objects.filter(left__category__name__in=['First'], right__category__name__in=['Second'])
+[<Relation: First - Second>]
+
+>>> Category.objects.filter(record__left_set__right__category__name='Second').order_by('name')
+[<Category: First>, <Category: Second>]
+
 """}

tests/regressiontests/select_related_regress/models.py

@@ -0,0 +1,60 @@
+from django.db import models
+
+class Building(models.Model):
+    name = models.CharField(max_length=10)
+
+    def __unicode__(self):
+        return u"Building: %s" % self.name
+
+class Device(models.Model):
+    building = models.ForeignKey('Building')
+    name = models.CharField(max_length=10)
+
+    def __unicode__(self):
+        return u"device '%s' in building %s" % (self.name, self.building)
+
+class Port(models.Model):
+    device = models.ForeignKey('Device')
+    number = models.CharField(max_length=10)
+
+    def __unicode__(self):
+        return u"%s/%s" % (self.device.name, self.number)
+
+class Connection(models.Model):
+    start = models.ForeignKey(Port, related_name='connection_start',
+            unique=True)
+    end = models.ForeignKey(Port, related_name='connection_end', unique=True)
+
+    def __unicode__(self):
+        return u"%s to %s" % (self.start, self.end)
+
+__test__ = {'API_TESTS': """
+Regression test for bug #7110. When using select_related(), we must query the
+Device and Building tables using two different aliases (each) in order to
+differentiate the start and end Connection fields. The net result is that both
+the "connections = ..." queries here should give the same results.
+
+>>> b=Building.objects.create(name='101')
+>>> dev1=Device.objects.create(name="router", building=b)
+>>> dev2=Device.objects.create(name="switch", building=b)
+>>> dev3=Device.objects.create(name="server", building=b)
+>>> port1=Port.objects.create(number='4',device=dev1)
+>>> port2=Port.objects.create(number='7',device=dev2)
+>>> port3=Port.objects.create(number='1',device=dev3)
+>>> c1=Connection.objects.create(start=port1, end=port2)
+>>> c2=Connection.objects.create(start=port2, end=port3)
+
+>>> connections=Connection.objects.filter(start__device__building=b, end__device__building=b).order_by('id')
+>>> [(c.id, unicode(c.start), unicode(c.end)) for c in connections]
+[(1, u'router/4', u'switch/7'), (2, u'switch/7', u'server/1')]
+
+>>> connections=Connection.objects.filter(start__device__building=b, end__device__building=b).select_related().order_by('id')
+>>> [(c.id, unicode(c.start), unicode(c.end)) for c in connections]
+[(1, u'router/4', u'switch/7'), (2, u'switch/7', u'server/1')]
+
+# This final query should only join seven tables (port, device and building
+# twice each, plus connection once).
+>>> connections.query.count_active_tables()
+7
+
+"""}