fix: trino thread app missing full context (#29981)

superset/db_engine_specs/trino.py

@@ -27,7 +27,7 @@ from typing import Any, TYPE_CHECKING
 import numpy as np
 import pandas as pd
 import pyarrow as pa
-from flask import current_app, Flask, g
+from flask import ctx, current_app, Flask, g
 from sqlalchemy import text
 from sqlalchemy.engine.reflection import Inspector
 from sqlalchemy.engine.url import URL
@@ -227,12 +227,22 @@ class TrinoEngineSpec(PrestoBaseEngineSpec):
         execute_event = threading.Event()
 
         def _execute(
-            results: dict[str, Any], event: threading.Event, app: Flask
+            results: dict[str, Any],
+            event: threading.Event,
+            app: Flask,
+            g_copy: ctx._AppCtxGlobals,
         ) -> None:
             logger.debug("Query %d: Running query: %s", query_id, sql)
 
             try:
+                # Flask contexts are local to the thread that handles the request.
+                # When you spawn a new thread, it does not inherit the contexts
+                # from the parent thread,
+                # meaning the g object and other context-bound variables are not
+                # accessible
                 with app.app_context():
+                    for key, value in g_copy.__dict__.items():
+                        setattr(g, key, value)
                     cls.execute(cursor, sql, query.database)
             except Exception as ex:  # pylint: disable=broad-except
                 results["error"] = ex
@@ -245,6 +255,7 @@ class TrinoEngineSpec(PrestoBaseEngineSpec):
                 execute_result,
                 execute_event,
                 current_app._get_current_object(),  # pylint: disable=protected-access
+                g._get_current_object(),  # pylint: disable=protected-access
             ),
         )
         execute_thread.start()

tests/unit_tests/db_engine_specs/test_trino.py

@@ -23,6 +23,7 @@ from unittest.mock import MagicMock, Mock, patch
 
 import pandas as pd
 import pytest
+from flask import g, has_app_context
 from pytest_mock import MockerFixture
 from requests.exceptions import ConnectionError as RequestsConnectionError
 from sqlalchemy import sql, text, types
@@ -435,6 +436,33 @@ def test_execute_with_cursor_in_parallel(app, mocker: MockerFixture):
         )
 
 
+def test_execute_with_cursor_app_context(app, mocker: MockerFixture):
+    """Test that `execute_with_cursor` still contains the current app context"""
+    from superset.db_engine_specs.trino import TrinoEngineSpec
+
+    mock_cursor = mocker.MagicMock()
+    mock_cursor.query_id = None
+
+    mock_query = mocker.MagicMock()
+    g.some_value = "some_value"
+
+    def _mock_execute(*args, **kwargs):
+        assert has_app_context()
+        assert g.some_value == "some_value"
+
+    with patch.object(TrinoEngineSpec, "execute", side_effect=_mock_execute):
+        with patch.dict(
+            "superset.config.DISALLOWED_SQL_FUNCTIONS",
+            {},
+            clear=True,
+        ):
+            TrinoEngineSpec.execute_with_cursor(
+                cursor=mock_cursor,
+                sql="SELECT 1 FROM foo",
+                query=mock_query,
+            )
+
+
 def test_get_columns(mocker: MockerFixture):
     """Test that ROW columns are not expanded without expand_rows"""
     from superset.db_engine_specs.trino import TrinoEngineSpec