Fixed #28077 -- Added support for PostgreSQL opclasses in Index.

Thanks Vinay Karanam for the initial patch.

tests/indexes/models.py

@@ -52,3 +52,8 @@ if connection.vendor == 'postgresql':
         headline = models.CharField(max_length=100, db_index=True)
         body = models.TextField(db_index=True)
         slug = models.CharField(max_length=40, unique=True)
+
+
+class IndexedArticle2(models.Model):
+    headline = models.CharField(max_length=100)
+    body = models.TextField()

tests/indexes/tests.py

@@ -1,11 +1,14 @@
-from unittest import skipUnless
+from unittest import skipIf, skipUnless
 
 from django.db import connection
+from django.db.models import Index
 from django.db.models.deletion import CASCADE
 from django.db.models.fields.related import ForeignKey
 from django.test import TestCase, TransactionTestCase
 
-from .models import Article, ArticleTranslation, IndexTogetherSingleList
+from .models import (
+    Article, ArticleTranslation, IndexedArticle2, IndexTogetherSingleList,
+)
 
 
 class SchemaIndexesTests(TestCase):
@@ -66,8 +69,33 @@ class SchemaIndexesTests(TestCase):
         index_sql = connection.schema_editor()._model_indexes_sql(IndexTogetherSingleList)
         self.assertEqual(len(index_sql), 1)
 
-    @skipUnless(connection.vendor == 'postgresql', "This is a postgresql-specific issue")
-    def test_postgresql_text_indexes(self):
+
+@skipIf(connection.vendor == 'postgresql', 'opclasses are PostgreSQL only')
+class SchemaIndexesNotPostgreSQLTests(TransactionTestCase):
+    available_apps = ['indexes']
+
+    def test_create_index_ignores_opclasses(self):
+        index = Index(
+            name='test_ops_class',
+            fields=['headline'],
+            opclasses=['varchar_pattern_ops'],
+        )
+        with connection.schema_editor() as editor:
+            # This would error if opclasses weren't ingored.
+            editor.add_index(IndexedArticle2, index)
+
+
+@skipUnless(connection.vendor == 'postgresql', 'PostgreSQL tests')
+class SchemaIndexesPostgreSQLTests(TransactionTestCase):
+    available_apps = ['indexes']
+    get_opclass_query = '''
+        SELECT opcname, c.relname FROM pg_opclass AS oc
+        JOIN pg_index as i on oc.oid = ANY(i.indclass)
+        JOIN pg_class as c on c.oid = i.indexrelid
+        WHERE c.relname = '%s'
+    '''
+
+    def test_text_indexes(self):
         """Test creation of PostgreSQL-specific text indexes (#12234)"""
         from .models import IndexedArticle
         index_sql = [str(statement) for statement in connection.schema_editor()._model_indexes_sql(IndexedArticle)]
@@ -78,12 +106,39 @@ class SchemaIndexesTests(TestCase):
         # index (#19441).
         self.assertIn('("slug" varchar_pattern_ops)', index_sql[4])
 
-    @skipUnless(connection.vendor == 'postgresql', "This is a postgresql-specific issue")
-    def test_postgresql_virtual_relation_indexes(self):
+    def test_virtual_relation_indexes(self):
         """Test indexes are not created for related objects"""
         index_sql = connection.schema_editor()._model_indexes_sql(Article)
         self.assertEqual(len(index_sql), 1)
 
+    def test_ops_class(self):
+        index = Index(
+            name='test_ops_class',
+            fields=['headline'],
+            opclasses=['varchar_pattern_ops'],
+        )
+        with connection.schema_editor() as editor:
+            editor.add_index(IndexedArticle2, index)
+        with editor.connection.cursor() as cursor:
+            cursor.execute(self.get_opclass_query % 'test_ops_class')
+            self.assertEqual(cursor.fetchall(), [('varchar_pattern_ops', 'test_ops_class')])
+
+    def test_ops_class_multiple_columns(self):
+        index = Index(
+            name='test_ops_class_multiple',
+            fields=['headline', 'body'],
+            opclasses=['varchar_pattern_ops', 'text_pattern_ops'],
+        )
+        with connection.schema_editor() as editor:
+            editor.add_index(IndexedArticle2, index)
+        with editor.connection.cursor() as cursor:
+            cursor.execute(self.get_opclass_query % 'test_ops_class_multiple')
+            expected_ops_classes = (
+                ('varchar_pattern_ops', 'test_ops_class_multiple'),
+                ('text_pattern_ops', 'test_ops_class_multiple'),
+            )
+            self.assertCountEqual(cursor.fetchall(), expected_ops_classes)
+
 
 @skipUnless(connection.vendor == 'mysql', 'MySQL tests')
 class SchemaIndexesMySQLTests(TransactionTestCase):