Fixed #26167 -- Added support for functional indexes.

Thanks Simon Charette, Mads Jensen, and Mariusz Felisiak for reviews.

Co-authored-by: Markus Holtermann <info@markusholtermann.eu>

2 files changed, 12 insertions, 3 deletions

diff --git a/django/db/backends/sqlite3/features.py b/django/db/backends/sqlite3/features.py
index 3348256c74..31055f8f99 100644
--- a/django/db/backends/sqlite3/features.py
+++ b/django/db/backends/sqlite3/features.py
@@ -38,6 +38,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_pragma_foreign_key_check = Database.sqlite_version_info >= (3, 20, 0)
     can_defer_constraint_checks = supports_pragma_foreign_key_check
     supports_functions_in_partial_indexes = Database.sqlite_version_info >= (3, 15, 0)
+    supports_expression_indexes = True
     supports_over_clause = Database.sqlite_version_info >= (3, 25, 0)
     supports_frame_range_fixed_distance = Database.sqlite_version_info >= (3, 28, 0)
     supports_aggregate_filter_clause = Database.sqlite_version_info >= (3, 30, 1)
diff --git a/django/db/backends/sqlite3/introspection.py b/django/db/backends/sqlite3/introspection.py
index 1d7ce3fabf..8c1d4582ab 100644
--- a/django/db/backends/sqlite3/introspection.py
+++ b/django/db/backends/sqlite3/introspection.py
@@ -416,9 +416,9 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
             if constraints[index]['index'] and not constraints[index]['unique']:
                 # SQLite doesn't support any index type other than b-tree
                 constraints[index]['type'] = Index.suffix
-                order_info = sql.split('(')[-1].split(')')[0].split(',')
-                orders = ['DESC' if info.endswith('DESC') else 'ASC' for info in order_info]
-                constraints[index]['orders'] = orders
+                orders = self._get_index_columns_orders(sql)
+                if orders is not None:
+                    constraints[index]['orders'] = orders
         # Get the PK
         pk_column = self.get_primary_key_column(cursor, table_name)
         if pk_column:
@@ -437,6 +437,14 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         constraints.update(self._get_foreign_key_constraints(cursor, table_name))
         return constraints
 
+    def _get_index_columns_orders(self, sql):
+        tokens = sqlparse.parse(sql)[0]
+        for token in tokens:
+            if isinstance(token, sqlparse.sql.Parenthesis):
+                columns = str(token).strip('()').split(', ')
+                return ['DESC' if info.endswith('DESC') else 'ASC' for info in columns]
+        return None
+
     def _get_column_collations(self, cursor, table_name):
         row = cursor.execute("""
             SELECT sql