SNOW-3071754: use internal describe for getting return type of sp (#4113)

Author: sfc-gh-yuwang

CHANGELOG.md

@@ -12,6 +12,10 @@
 - Fixed a bug when saving a fdn table into an iceberg table in overwrite mode, error is raised because `StringType` is saved in wrong length.
 - Fixed a bug in `ai_complete` where `model_parameters` and `response_format` values containing single quotes would generate malformed SQL.
 
+#### Improvements
+
+- Use internal describe to get return type when executing a stored procedure.
+
 ## 1.47.0 (2026-03-05)
 
 ### Snowpark Python API Updates

src/snowflake/snowpark/session.py

@@ -4509,10 +4509,11 @@ def _infer_is_return_table(
             # describe procedure returns two column table with columns - property and value
             # the second row in the sproc_desc is property=returns and value=<return type of procedure>
             # when no procedure of the signature is found, SQL exception is raised
-            sproc_desc = self._run_query(
+            sproc_desc = self._conn.run_query(
                 f"describe procedure {func_signature}",
+                _is_internal=True,
                 log_on_exception=log_on_exception,
-            )
+            )["data"]
             return_type = sproc_desc[1][1]
             return return_type.upper().startswith("TABLE")
         except Exception as exc:

tests/unit/test_session.py

@@ -774,6 +774,23 @@ def test_get_default_artifact_repository():
 
         assert mocked_run_query.call_count == 1
 
+
+def test_infer_is_return_table_uses_internal_describe():
+    fake_server_connection = mock.create_autospec(ServerConnection)
+    fake_server_connection._thread_safe_session_enabled = True
+    fake_server_connection.run_query = MagicMock(
+        return_value={"data": [("signature", "dummy"), ("returns", "TABLE (A NUMBER)")]}
+    )
+    session = Session(fake_server_connection)
+
+    assert session._infer_is_return_table("test_proc") is True
+
+    fake_server_connection.run_query.assert_called_once_with(
+        "describe procedure TEST_PROC()",
+        _is_internal=True,
+        log_on_exception=False,
+    )
+
     with mock.patch.object(
         session, "_run_query", side_effect=ProgrammingError("Not found")
     ) as mocked_run_query, mock.patch.object(