Ticket #10673: annotation_test.diff

tests/regressiontests/aggregation_regress/models.py

@@ -15 +15 @@
     def __unicode__(self):
         return self.name
 
+class PublisherManager(models.Manager):
+    use_for_related_fields = True   # Line A
+    def get_query_set(self):
+        qs = super(PublisherManager, self).get_query_set()
+        qs = qs.annotate(n_books=models.Count('book'))  # Line B
+        return qs
+
 class Publisher(models.Model):
     name = models.CharField(max_length=300)
     num_awards = models.IntegerField()
 
+    objects_alternate = PublisherManager() # Line C
+    objects = models.Manager() # Line D
+
     def __unicode__(self):
         return self.name
 
@@ -259 +269 @@
 >>> Book.objects.annotate(Count('publisher')).values('publisher').count()
 6
 
+# If the default manager adds an annotation and sets use_for_related_fields, saves can fail.
+>>> p = Publisher.objects_alternate.all()[0]
+>>> p.n_books
+2
+>>> p.save() # Failure. Commenting line A or B or swapping lines C and D, above, will yield success.
 """
 }