fix(core): Keep submodules of safe modules in native Python runner (#20284)

packages/@n8n/task-runner-python/src/task_executor.py

@@ -405,8 +405,12 @@ class TaskExecutor:
         else:
             safe_modules.update(external_allow)
 
+        # keep modules marked as safe and submodules of those
         modules_to_remove = [
-            name for name in sys.modules.keys() if name not in safe_modules
+            name
+            for name in sys.modules.keys()
+            if name not in safe_modules
+            and not any(name.startswith(safe + ".") for safe in safe_modules)
         ]
 
         for module_name in modules_to_remove:

packages/@n8n/task-runner-python/tests/fixtures/task_runner_manager.py

@@ -27,9 +27,11 @@ class TaskRunnerManager:
         self,
         task_broker_url: str = LOCAL_TASK_BROKER_URL,
         graceful_shutdown_timeout: float | None = None,
+        custom_env: dict[str, str] | None = None,
     ):
         self.task_broker_url = task_broker_url
         self.graceful_shutdown_timeout = graceful_shutdown_timeout
+        self.custom_env = custom_env or {}
         self.subprocess: asyncio.subprocess.Process | None = None
         self.stdout_buffer: list[str] = []
         self.stderr_buffer: list[str] = []
@@ -49,6 +51,7 @@ class TaskRunnerManager:
                 self.graceful_shutdown_timeout
             )
         env_vars["PYTHONPATH"] = str(project_root)
+        env_vars.update(self.custom_env)
 
         self.subprocess = await asyncio.create_subprocess_exec(
             sys.executable,

packages/@n8n/task-runner-python/tests/integration/conftest.py

@@ -27,6 +27,18 @@ async def broker():
     await broker.stop()
 
 
+@pytest_asyncio.fixture
+async def manager_with_stdlib_wildcard():
+    manager = TaskRunnerManager(
+        custom_env={
+            "N8N_RUNNERS_STDLIB_ALLOW": "*",
+        }
+    )
+    await manager.start()
+    yield manager
+    await manager.stop()
+
+
 def create_task_settings(
     code: str,
     node_mode: str,

packages/@n8n/task-runner-python/tests/integration/test_execution.py

@@ -230,3 +230,19 @@ async def test_timeout_during_execution(broker, manager):
 
     assert error_msg["taskId"] == task_id
     assert "timed out" in error_msg["error"]["message"].lower()
+
+
+@pytest.mark.asyncio
+async def test_stdlib_submodules_with_wildcard(broker, manager_with_stdlib_wildcard):
+    task_id = nanoid()
+    code = textwrap.dedent("""
+        from collections.abc import Iterable
+        result = isinstance([1, 2, 3], Iterable)
+        return [{"json": {"is_iterable": result}}]
+    """)
+    task_settings = create_task_settings(code=code, node_mode="all_items")
+    await broker.send_task(task_id=task_id, task_settings=task_settings)
+
+    result = await wait_for_task_done(broker, task_id)
+
+    assert result["data"]["result"] == [{"json": {"is_iterable": True}}]