move description to List[Tuple]

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/backend/thrift_backend.py

@@ -727,7 +727,7 @@ def _col_to_description(col):
         else:
             precision, scale = None, None
 
-        return [col.columnName, cleaned_type, None, None, precision, scale, None]
+        return (col.columnName, cleaned_type, None, None, precision, scale, None)
 
     @staticmethod
     def _hive_schema_to_description(t_table_schema):

src/databricks/sql/backend/types.py

@@ -423,7 +423,7 @@ class ExecuteResponse:
 
     command_id: CommandId
     status: CommandState
-    description: Optional[List[List[Any]]] = None
+    description: Optional[List[Tuple]] = None
     has_more_rows: bool = False
     has_been_closed_server_side: bool = False
     lz4_compressed: bool = True

src/databricks/sql/utils.py

@@ -8,7 +8,7 @@
 from collections.abc import Iterable
 from decimal import Decimal
 from enum import Enum
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Dict, List, Optional, Tuple, Union
 import re
 
 import lz4.frame
@@ -57,7 +57,7 @@ def build_queue(
         max_download_threads: int,
         ssl_options: SSLOptions,
         lz4_compressed: bool = True,
-        description: Optional[List[List[Any]]] = None,
+        description: Optional[List[Tuple]] = None,
     ) -> ResultSetQueue:
         """
         Factory method to build a result set queue.
@@ -206,7 +206,7 @@ def __init__(
         start_row_offset: int = 0,
         result_links: Optional[List[TSparkArrowResultLink]] = None,
         lz4_compressed: bool = True,
-        description: Optional[List[List[Any]]] = None,
+        description: Optional[List[Tuple]] = None,
     ):
         """
         A queue-like wrapper over CloudFetch arrow batches.

tests/unit/test_thrift_backend.py

@@ -511,10 +511,10 @@ def test_hive_schema_to_description_preserves_column_names_and_types(self):
         self.assertEqual(
             description,
             [
-                ["column 1", "int", None, None, None, None, None],
-                ["column 2", "boolean", None, None, None, None, None],
-                ["column 2", "map", None, None, None, None, None],
-                ["", "struct", None, None, None, None, None],
+                ("column 1", "int", None, None, None, None, None),
+                ("column 2", "boolean", None, None, None, None, None),
+                ("column 2", "map", None, None, None, None, None),
+                ("", "struct", None, None, None, None, None),
             ],
         )
 
@@ -549,7 +549,7 @@ def test_hive_schema_to_description_preserves_scale_and_precision(self):
         self.assertEqual(
             description,
             [
-                ["column 1", "decimal", None, None, 10, 100, None],
+                ("column 1", "decimal", None, None, 10, 100, None),
             ],
         )