fix mixture of sync/async sockets in IOPubThread

ipykernel/inprocess/ipkernel.py

@@ -6,6 +6,7 @@
 import logging
 import sys
 from contextlib import contextmanager
+from typing import cast
 
 from anyio import TASK_STATUS_IGNORED
 from anyio.abc import TaskStatus
@@ -146,7 +147,8 @@ def callback(msg):
                 assert frontend is not None
                 frontend.iopub_channel.call_handlers(msg)
 
-        self.iopub_thread.socket.on_recv = callback
+        iopub_socket = cast(DummySocket, self.iopub_thread.socket)
+        iopub_socket.on_recv = callback
 
     # ------ Trait initializers -----------------------------------------------
 

ipykernel/inprocess/socket.py

@@ -63,3 +63,6 @@ async def poll(self, timeout=0):
         assert timeout == 0
         statistics = self.in_receive_stream.statistics()
         return statistics.current_buffer_used != 0
+
+    def close(self):
+        pass

ipykernel/iostream.py

@@ -3,6 +3,8 @@
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
+from __future__ import annotations
+
 import atexit
 import contextvars
 import io
@@ -15,7 +17,7 @@
 from collections import defaultdict, deque
 from io import StringIO, TextIOBase
 from threading import Event, Thread, local
-from typing import Any, Callable, Optional
+from typing import Any, Callable
 
 import zmq
 from anyio import create_task_group, run, sleep, to_thread
@@ -25,8 +27,8 @@
 # Globals
 # -----------------------------------------------------------------------------
 
-MASTER = 0
-CHILD = 1
+_PARENT = 0
+_CHILD = 1
 
 PIPE_BUFFER_SIZE = 1000
 
@@ -87,9 +89,16 @@ def __init__(self, socket, pipe=False):
             Whether this process should listen for IOPub messages
             piped from subprocesses.
         """
-        self.socket = socket
+        # ensure all of our sockets as sync zmq.Sockets
+        # don't create async wrappers until we are within the appropriate coroutines
+        self.socket: zmq.Socket[bytes] | None = zmq.Socket(socket)
+        if self.socket.context is None:
+            # bug in pyzmq, shadow socket doesn't always inherit context attribute
+            self.socket.context = socket.context  # type:ignore[unreachable]
+        self._context = socket.context
+
         self.background_socket = BackgroundSocket(self)
-        self._master_pid = os.getpid()
+        self._main_pid = os.getpid()
         self._pipe_flag = pipe
         if pipe:
             self._setup_pipe_in()
@@ -106,8 +115,7 @@ def __init__(self, socket, pipe=False):
 
     def _setup_event_pipe(self):
         """Create the PULL socket listening for events that should fire in this thread."""
-        ctx = self.socket.context
-        self._pipe_in0 = ctx.socket(zmq.PULL)
+        self._pipe_in0 = self._context.socket(zmq.PULL, socket_class=zmq.Socket)
         self._pipe_in0.linger = 0
 
         _uuid = b2a_hex(os.urandom(16)).decode("ascii")
@@ -141,8 +149,8 @@ def _event_pipe(self):
             event_pipe = self._local.event_pipe
         except AttributeError:
             # new thread, new event pipe
-            ctx = zmq.Context(self.socket.context)
-            event_pipe = ctx.socket(zmq.PUSH)
+            # create sync base socket
+            event_pipe = self._context.socket(zmq.PUSH, socket_class=zmq.Socket)
             event_pipe.linger = 0
             event_pipe.connect(self._event_interface)
             self._local.event_pipe = event_pipe
@@ -161,9 +169,11 @@ async def _handle_event(self):
         Whenever *an* event arrives on the event stream,
         *all* waiting events are processed in order.
         """
+        # create async wrapper within coroutine
+        pipe_in = zmq.asyncio.Socket(self._pipe_in0)
         try:
             while True:
-                await self._pipe_in0.recv()
+                await pipe_in.recv()
                 # freeze event count so new writes don't extend the queue
                 # while we are processing
                 n_events = len(self._events)
@@ -177,12 +187,12 @@ async def _handle_event(self):
 
     def _setup_pipe_in(self):
         """setup listening pipe for IOPub from forked subprocesses"""
-        ctx = self.socket.context
+        ctx = self._context
 
         # use UUID to authenticate pipe messages
         self._pipe_uuid = os.urandom(16)
 
-        self._pipe_in1 = ctx.socket(zmq.PULL)
+        self._pipe_in1 = ctx.socket(zmq.PULL, socket_class=zmq.Socket)
         self._pipe_in1.linger = 0
 
         try:
@@ -199,6 +209,8 @@ def _setup_pipe_in(self):
 
     async def _handle_pipe_msgs(self):
         """handle pipe messages from a subprocess"""
+        # create async wrapper within coroutine
+        self._async_pipe_in1 = zmq.asyncio.Socket(self._pipe_in1)
         try:
             while True:
                 await self._handle_pipe_msg()
@@ -209,8 +221,8 @@ async def _handle_pipe_msgs(self):
 
     async def _handle_pipe_msg(self, msg=None):
         """handle a pipe message from a subprocess"""
-        msg = msg or await self._pipe_in1.recv_multipart()
-        if not self._pipe_flag or not self._is_master_process():
+        msg = msg or await self._async_pipe_in1.recv_multipart()
+        if not self._pipe_flag or not self._is_main_process():
             return
         if msg[0] != self._pipe_uuid:
             print("Bad pipe message: %s", msg, file=sys.__stderr__)
@@ -225,14 +237,14 @@ def _setup_pipe_out(self):
         pipe_out.connect("tcp://127.0.0.1:%i" % self._pipe_port)
         return ctx, pipe_out
 
-    def _is_master_process(self):
-        return os.getpid() == self._master_pid
+    def _is_main_process(self):
+        return os.getpid() == self._main_pid
 
     def _check_mp_mode(self):
         """check for forks, and switch to zmq pipeline if necessary"""
-        if not self._pipe_flag or self._is_master_process():
-            return MASTER
-        return CHILD
+        if not self._pipe_flag or self._is_main_process():
+            return _PARENT
+        return _CHILD
 
     def start(self):
         """Start the IOPub thread"""
@@ -265,7 +277,8 @@ def close(self):
         self._pipe_in0.close()
         if self._pipe_flag:
             self._pipe_in1.close()
-        self.socket.close()
+        if self.socket is not None:
+            self.socket.close()
         self.socket = None
 
     @property
@@ -301,12 +314,12 @@ def _really_send(self, msg, *args, **kwargs):
             return
 
         mp_mode = self._check_mp_mode()
-
-        if mp_mode != CHILD:
-            # we are master, do a regular send
+        if mp_mode != _CHILD:
+            # we are the main parent process, do a regular send
+            assert self.socket is not None
             self.socket.send_multipart(msg, *args, **kwargs)
         else:
-            # we are a child, pipe to master
+            # we are a child, pipe to parent process
             # new context/socket for every pipe-out
             # since forks don't teardown politely, use ctx.term to ensure send has completed
             ctx, pipe_out = self._setup_pipe_out()
@@ -379,7 +392,7 @@ class OutStream(TextIOBase):
     flush_interval = 0.2
     topic = None
     encoding = "UTF-8"
-    _exc: Optional[Any] = None
+    _exc: Any = None
 
     def fileno(self):
         """
@@ -477,7 +490,7 @@ def __init__(
         self._thread_to_parent = {}
         self._thread_to_parent_header = {}
         self._parent_header_global = {}
-        self._master_pid = os.getpid()
+        self._main_pid = os.getpid()
         self._flush_pending = False
         self._subprocess_flush_pending = False
         self._buffer_lock = threading.RLock()
@@ -569,8 +582,8 @@ def _setup_stream_redirects(self, name):
         self.watch_fd_thread.daemon = True
         self.watch_fd_thread.start()
 
-    def _is_master_process(self):
-        return os.getpid() == self._master_pid
+    def _is_main_process(self):
+        return os.getpid() == self._main_pid
 
     def set_parent(self, parent):
         """Set the parent header."""
@@ -674,7 +687,7 @@ def _flush(self):
                     ident=self.topic,
                 )
 
-    def write(self, string: str) -> Optional[int]:  # type:ignore[override]
+    def write(self, string: str) -> int:
         """Write to current stream after encoding if necessary
 
         Returns
@@ -700,15 +713,15 @@ def write(self, string: str) -> Optional[int]:  # type:ignore[override]
             msg = "I/O operation on closed file"
             raise ValueError(msg)
 
-        is_child = not self._is_master_process()
+        is_child = not self._is_main_process()
         # only touch the buffer in the IO thread to avoid races
         with self._buffer_lock:
             self._buffers[frozenset(parent.items())].write(string)
         if is_child:
             # mp.Pool cannot be trusted to flush promptly (or ever),
             # and this helps.
             if self._subprocess_flush_pending:
-                return None
+                return 0
             self._subprocess_flush_pending = True
             # We can not rely on self._io_loop.call_later from a subprocess
             self.pub_thread.schedule(self._flush)

tests/test_io.py

@@ -15,7 +15,7 @@
 import zmq.asyncio
 from jupyter_client.session import Session
 
-from ipykernel.iostream import MASTER, BackgroundSocket, IOPubThread, OutStream
+from ipykernel.iostream import _PARENT, BackgroundSocket, IOPubThread, OutStream
 
 
 @pytest.fixture()
@@ -73,7 +73,7 @@ async def test_io_thread(anyio_backend, iopub_thread):
     ctx1, pipe = thread._setup_pipe_out()
     pipe.close()
     thread._pipe_in1.close()
-    thread._check_mp_mode = lambda: MASTER
+    thread._check_mp_mode = lambda: _PARENT
     thread._really_send([b"hi"])
     ctx1.destroy()
     thread.stop()

tests/test_kernel.py

@@ -32,10 +32,10 @@
 )
 
 
-def _check_master(kc, expected=True, stream="stdout"):
+def _check_main(kc, expected=True, stream="stdout"):
     execute(kc=kc, code="import sys")
     flush_channels(kc)
-    msg_id, content = execute(kc=kc, code="print(sys.%s._is_master_process())" % stream)
+    msg_id, content = execute(kc=kc, code="print(sys.%s._is_main_process())" % stream)
     stdout, stderr = assemble_output(kc.get_iopub_msg)
     assert stdout.strip() == repr(expected)
 
@@ -56,7 +56,7 @@ def test_simple_print():
         stdout, stderr = assemble_output(kc.get_iopub_msg)
         assert stdout == "hi\n"
         assert stderr == ""
-        _check_master(kc, expected=True)
+        _check_main(kc, expected=True)
 
 
 def test_print_to_correct_cell_from_thread():
@@ -168,7 +168,7 @@ def test_capture_fd():
         stdout, stderr = assemble_output(iopub)
         assert stdout == "capsys\n"
         assert stderr == ""
-        _check_master(kc, expected=True)
+        _check_main(kc, expected=True)
 
 
 @pytest.mark.skip(reason="Currently don't capture during test as pytest does its own capturing")
@@ -182,7 +182,7 @@ def test_subprocess_peek_at_stream_fileno():
         stdout, stderr = assemble_output(iopub)
         assert stdout == "CAP1\nCAP2\n"
         assert stderr == ""
-        _check_master(kc, expected=True)
+        _check_main(kc, expected=True)
 
 
 def test_sys_path():
@@ -218,7 +218,7 @@ def test_sys_path_profile_dir():
 def test_subprocess_print():
     """printing from forked mp.Process"""
     with new_kernel() as kc:
-        _check_master(kc, expected=True)
+        _check_main(kc, expected=True)
         flush_channels(kc)
         np = 5
         code = "\n".join(
@@ -238,8 +238,8 @@ def test_subprocess_print():
         for n in range(np):
             assert stdout.count(str(n)) == 1, stdout
         assert stderr == ""
-        _check_master(kc, expected=True)
-        _check_master(kc, expected=True, stream="stderr")
+        _check_main(kc, expected=True)
+        _check_main(kc, expected=True, stream="stderr")
 
 
 @flaky(max_runs=3)
@@ -261,8 +261,8 @@ def test_subprocess_noprint():
         assert stdout == ""
         assert stderr == ""
 
-        _check_master(kc, expected=True)
-        _check_master(kc, expected=True, stream="stderr")
+        _check_main(kc, expected=True)
+        _check_main(kc, expected=True, stream="stderr")
 
 
 @flaky(max_runs=3)
@@ -287,8 +287,8 @@ def test_subprocess_error():
         assert stdout == ""
         assert "ValueError" in stderr
 
-        _check_master(kc, expected=True)
-        _check_master(kc, expected=True, stream="stderr")
+        _check_main(kc, expected=True)
+        _check_main(kc, expected=True, stream="stderr")
 
 
 # raw_input tests