Fixed #16855 -- select_related() chains as expected.

select_related('foo').select_related('bar') is now equivalent to
select_related('foo', 'bar').

Also reworded docs to recommend select_related(*fields) over select_related()

2 files changed, 19 insertions, 1 deletions

diff --git a/tests/select_related/models.py b/tests/select_related/models.py
index ec41957adf..11ef7db91f 100644
--- a/tests/select_related/models.py
+++ b/tests/select_related/models.py
@@ -66,3 +66,12 @@ class Species(models.Model):
     genus = models.ForeignKey(Genus)
     def __str__(self):
         return self.name
+
+# and we'll invent a new thing so we have a model with two foreign keys
+@python_2_unicode_compatible
+class HybridSpecies(models.Model):
+    name = models.CharField(max_length=50)
+    parent_1 = models.ForeignKey(Species, related_name='child_1')
+    parent_2 = models.ForeignKey(Species, related_name='child_2')
+    def __str__(self):
+        return self.name
diff --git a/tests/select_related/tests.py b/tests/select_related/tests.py
index f07e28df99..8949d99788 100644
--- a/tests/select_related/tests.py
+++ b/tests/select_related/tests.py
@@ -2,7 +2,7 @@ from __future__ import unicode_literals
 
 from django.test import TestCase
 
-from .models import Domain, Kingdom, Phylum, Klass, Order, Family, Genus, Species
+from .models import Domain, Kingdom, Phylum, Klass, Order, Family, Genus, Species, HybridSpecies
 
 
 class SelectRelatedTests(TestCase):
@@ -144,3 +144,12 @@ class SelectRelatedTests(TestCase):
     def test_none_clears_list(self):
         queryset = Species.objects.select_related('genus').select_related(None)
         self.assertEqual(queryset.query.select_related, False)
+
+    def test_chaining(self):
+        parent_1, parent_2 = Species.objects.all()[:2]
+        HybridSpecies.objects.create(name='hybrid', parent_1=parent_1, parent_2=parent_2)
+        queryset = HybridSpecies.objects.select_related('parent_1').select_related('parent_2')
+        with self.assertNumQueries(1):
+            obj = queryset[0]
+            self.assertEquals(obj.parent_1, parent_1)
+            self.assertEquals(obj.parent_2, parent_2)