-

ipykernel/kernelbase.py

@@ -419,6 +419,15 @@ async def shell_main(self, subshell_id: str | None):
 
         async with create_task_group() as tg:
             tg.start_soon(self.process_shell, socket)
+            if subshell_id is None:
+                # Main subshell.
+                await to_thread.run_sync(self.shell_stop.wait)
+
+                if not self._eventloop_set.is_set():
+                    # Stop the async task that is waiting for the eventloop to be set.
+                    self._eventloop_set.set()
+
+                tg.cancel_scope.cancel()
 
     async def process_shell(self, socket=None):
         # socket=None is valid if kernel subshells are not supported.
@@ -568,14 +577,6 @@ async def start(self, *, task_status: TaskStatus = TASK_STATUS_IGNORED) -> None:
                 if not self._is_test and self.shell_socket is not None:
                     tg.start_soon(self.shell_main, None)
 
-            await to_thread.run_sync(self.shell_stop.wait)
-
-            if not self._eventloop_set.is_set():
-                # Stop the async task that is waiting for the eventloop to be set.
-                self._eventloop_set.set()
-
-            tg.cancel_scope.cancel()
-
     def stop(self):
         self.shell_stop.set()
         self.control_stop.set()

tests/conftest.py

@@ -19,13 +19,6 @@
 from ipykernel.kernelbase import Kernel
 from ipykernel.zmqshell import ZMQInteractiveShell
 
-# ensure we don't leak history managers
-if os.name != "nt":
-    import tracemalloc
-
-    tracemalloc.start(20)
-    HistoryManager._max_inst = 1
-
 
 @pytest.fixture(scope="session", autouse=True)
 def _garbage_collection(request):
@@ -43,6 +36,10 @@ def _garbage_collection(request):
 except ModuleNotFoundError:
     tracemalloc = None
 
+# ensure we don't leak history managers
+if os.name != "nt":
+    HistoryManager._max_inst = 1
+
 
 pytestmark = pytest.mark.anyio
 
@@ -225,8 +222,6 @@ async def ipkernel(anyio_backend):
             yield kernel
         finally:
             kernel.destroy()
-            kernel.shell._atexit_once()
-            kernel.shell.configurables = []
             ZMQInteractiveShell.clear_instance()
 
 

tests/test_comm.py

@@ -7,7 +7,6 @@
 from ipykernel.kernelbase import Kernel
 
 
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_comm(kernel: Kernel) -> None:
     manager = CommManager(kernel=kernel)
     kernel.comm_manager = manager  # type:ignore
@@ -35,7 +34,6 @@ def on_message(msg):
     assert c.target_name == "bar"
 
 
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_comm_manager(kernel: Kernel) -> None:
     manager = CommManager(kernel=kernel)
     msgs = []
@@ -101,7 +99,6 @@ def on_msg(msg):
     assert comm._closed
 
 
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_comm_in_manager(ipkernel: IPythonKernel) -> None:
     with pytest.deprecated_call():
         comm = Comm()

tests/test_eventloop.py

@@ -59,7 +59,6 @@ def _setup_env():
 
 @windows_skip
 @pytest.mark.skipif(sys.platform == "darwin", reason="hangs on macos")
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_tk_loop(kernel):
     def do_thing():
         time.sleep(1)
@@ -91,19 +90,16 @@ def do_thing():
 
 
 @windows_skip
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_enable_gui(kernel):
     enable_gui("tk", kernel)
 
 
 @pytest.mark.skipif(sys.platform != "darwin", reason="MacOS-only")
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_cocoa_loop(kernel):
     loop_cocoa(kernel)
 
 
 @pytest.mark.parametrize("gui", qt_guis_avail)
-@pytest.mark.parametrize("anyio_backend", ["asyncio"])
 def test_qt_enable_gui(gui, kernel, capsys):
     if os.getenv("GITHUB_ACTIONS", None) == "true" and gui == "qt5":
         pytest.skip("Qt5 and GitHub action crash CPython")

tests/test_zmq_shell.py

@@ -233,7 +233,6 @@ def test_magics(tmp_path):
         socket.close()
         context.destroy()
     finally:
-        shell._atexit_once()
         shell.configurables = []
         InteractiveShell.clear_instance()
 
@@ -258,7 +257,6 @@ def test_zmq_interactive_shell(kernel):
             shell.system_piped("dir")
         shell.ask_exit()
     finally:
-        shell._atexit_once()
         shell.configurables = []
         ZMQInteractiveShell.clear_instance()