From d2f087f092db01f3933de0fc7a4220bc2a8b269d Mon Sep 17 00:00:00 2001
From: Matt Westcott <matthew@torchbox.com>
Date: Sat, 23 Apr 2016 13:22:48 +0100
Subject: [PATCH] Remove useless get_indexed_objects method from TagSearchable
 (#2498)

Indexing the tags of TagSearchable subclasses (such as wagtailimages.Image) is done by following
the model's 'tags' relation, and wagtailsearch is smart enough to prefetch that automatically
(as the test demonstrates). Prefetching 'tagged_items__tag' just adds two useless queries :-)
---
 wagtail/wagtailadmin/taggable.py           |  4 ----
 wagtail/wagtailimages/tests/test_models.py | 15 +++++++++++++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/wagtail/wagtailadmin/taggable.py b/wagtail/wagtailadmin/taggable.py
index 56b4f9d82..d174c16a6 100644
--- a/wagtail/wagtailadmin/taggable.py
+++ b/wagtail/wagtailadmin/taggable.py
@@ -21,10 +21,6 @@ class TagSearchable(index.Indexed):
         ]),
     ], name='search_fields on TagSearchable subclasses')
 
-    @classmethod
-    def get_indexed_objects(cls):
-        return super(TagSearchable, cls).get_indexed_objects().prefetch_related('tagged_items__tag')
-
     @classmethod
     def popular_tags(cls):
         content_type = ContentType.objects.get_for_model(cls)
diff --git a/wagtail/wagtailimages/tests/test_models.py b/wagtail/wagtailimages/tests/test_models.py
index 58a715d68..146e69ad2 100644
--- a/wagtail/wagtailimages/tests/test_models.py
+++ b/wagtail/wagtailimages/tests/test_models.py
@@ -132,6 +132,21 @@ class TestImageQuerySet(TestCase):
         results = Image.objects.order_by('-title').search("Test")
         self.assertEqual(list(results), [zzz_image, aaa_image])
 
+    def test_search_indexing_prefetches_tags(self):
+        for i in range(0, 10):
+            image = Image.objects.create(
+                title="Test image %d" % i,
+                file=get_test_image_file(),
+            )
+            image.tags.add('aardvark', 'artichoke', 'armadillo')
+
+        with self.assertNumQueries(2):
+            results = {
+                image.title: [tag.name for tag in image.tags.all()]
+                for image in Image.get_indexed_objects()
+            }
+            self.assertTrue('aardvark' in results['Test image 0'])
+
 
 class TestImagePermissions(TestCase):
     def setUp(self):