Fixed #30903 -- Fixed migrations crash on PostgreSQL when adding Index with opclasses and ordering.

AUTHORS

@@ -340,6 +340,7 @@ answer newbie questions, and generally made Django that much better:
     Gustavo Picon
     hambaloney
     Hang Park <hangpark@kaist.ac.kr>
+    Hannes Ljungberg <hannes.ljungberg@gmail.com>
     Hannes Struß <x@hannesstruss.de>
     Hasan Ramezani <hasan.r67@gmail.com>
     Hawkeye

django/db/backends/ddl_references.py

@@ -110,13 +110,14 @@ class IndexColumns(Columns):
 
     def __str__(self):
         def col_str(column, idx):
-            try:
-                col = self.quote_name(column) + self.col_suffixes[idx]
-            except IndexError:
-                col = self.quote_name(column)
             # Index.__init__() guarantees that self.opclasses is the same
             # length as self.columns.
-            return '{} {}'.format(col, self.opclasses[idx])
+            col = '{} {}'.format(self.quote_name(column), self.opclasses[idx])
+            try:
+                col = '{} {}'.format(col, self.col_suffixes[idx])
+            except IndexError:
+                pass
+            return col
 
         return ', '.join(col_str(column, idx) for idx, column in enumerate(self.columns))
 

docs/releases/2.2.7.txt

@@ -17,3 +17,7 @@ Bugfixes
 * Prevented :option:`migrate --plan` from showing that ``RunPython`` operations
   are irreversible when ``reverse_code`` callables don't have docstrings or
   when showing a forward migration plan (:ticket:`30870`).
+
+* Fixed migrations crash on PostgreSQL when adding an
+  :class:`~django.db.models.Index` with fields ordering and
+  :attr:`~.Index.opclasses` (:ticket:`30903`).

tests/indexes/tests.py

@@ -196,6 +196,33 @@ class SchemaIndexesPostgreSQLTests(TransactionTestCase):
             cursor.execute(self.get_opclass_query % indexname)
             self.assertCountEqual(cursor.fetchall(), [('text_pattern_ops', indexname)])
 
+    def test_ops_class_descending(self):
+        indexname = 'test_ops_class_ordered'
+        index = Index(
+            name=indexname,
+            fields=['-body'],
+            opclasses=['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 % indexname)
+            self.assertCountEqual(cursor.fetchall(), [('text_pattern_ops', indexname)])
+
+    def test_ops_class_descending_partial(self):
+        indexname = 'test_ops_class_ordered_partial'
+        index = Index(
+            name=indexname,
+            fields=['-body'],
+            opclasses=['text_pattern_ops'],
+            condition=Q(headline__contains='China'),
+        )
+        with connection.schema_editor() as editor:
+            editor.add_index(IndexedArticle2, index)
+        with editor.connection.cursor() as cursor:
+            cursor.execute(self.get_opclass_query % indexname)
+            self.assertCountEqual(cursor.fetchall(), [('text_pattern_ops', indexname)])
+
 
 @skipUnless(connection.vendor == 'mysql', 'MySQL tests')
 class SchemaIndexesMySQLTests(TransactionTestCase):