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fix: use socket .get() instead of .getsockopt() to prevent deaf loop #8

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Merged
jph00 merged 1 commit into from
Jun 10, 2026
Merged

fix: use socket .get() instead of .getsockopt() to prevent deaf loop #8

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12 changes: 8 additions & 4 deletions conkernelclient/core.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,12 +32,16 @@ def _send(self, stream, msg_or_type, content=None, parent=None, ident=None,
buffers=None, track=False, header=None, metadata=None):
msg = self._orig_send(stream, msg_or_type, content=content, parent=parent,
ident=ident, buffers=buffers, track=track, header=header, metadata=metadata)
# Force a sync, ensuring the send is fully registered internally
# Avoids a race where the lock releases, another thread immediately calls send(),
# and now 2 threads are interacting with the internal state before I/O thread has caught up
# Session.send sends via a SYNC shadow of the asyncio socket (zmq.Socket.shadow), which runs
# libzmq process_commands() and consumes the FD edge a buffered reply may have signalled —
# a recv parked in poll(None) on that edge would then sleep forever. Reading EVENTS through
# the async override (_AsyncSocket.get) makes pyzmq re-schedule _handle_events for pending
# recv/poll futures, compensating the consumed edge. It MUST be .get(): pyzmq aliases
# `getsockopt = SocketBase.get` at class level, so .getsockopt() bypasses the override
# and consumes the edge without rescheduling.
if stream:
if hasattr(stream, 'io_thread'): stream.io_thread.socket.get(zmq.EVENTS)
elif hasattr(stream, 'getsockopt'): stream.getsockopt(zmq.EVENTS)
elif hasattr(stream, 'get'): stream.get(zmq.EVENTS)
return msg

Session.send = _send
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12 changes: 8 additions & 4 deletions nbs/00_core.ipynb
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Original file line number Diff line number Diff line change
Expand Up @@ -103,12 +103,16 @@
" buffers=None, track=False, header=None, metadata=None):\n",
" msg = self._orig_send(stream, msg_or_type, content=content, parent=parent,\n",
" ident=ident, buffers=buffers, track=track, header=header, metadata=metadata)\n",
" # Force a sync, ensuring the send is fully registered internally\n",
" # Avoids a race where the lock releases, another thread immediately calls send(),\n",
" # and now 2 threads are interacting with the internal state before I/O thread has caught up\n",
" # Session.send sends via a SYNC shadow of the asyncio socket (zmq.Socket.shadow), which runs\n",
" # libzmq process_commands() and consumes the FD edge a buffered reply may have signalled —\n",
" # a recv parked in poll(None) on that edge would then sleep forever. Reading EVENTS through\n",
" # the async override (_AsyncSocket.get) makes pyzmq re-schedule _handle_events for pending\n",
" # recv/poll futures, compensating the consumed edge. It MUST be .get(): pyzmq aliases\n",
" # `getsockopt = SocketBase.get` at class level, so .getsockopt() bypasses the override\n",
" # and consumes the edge without rescheduling.\n",
" if stream:\n",
" if hasattr(stream, 'io_thread'): stream.io_thread.socket.get(zmq.EVENTS)\n",
" elif hasattr(stream, 'getsockopt'): stream.getsockopt(zmq.EVENTS)\n",
" elif hasattr(stream, 'get'): stream.get(zmq.EVENTS)\n",
" return msg\n",
"\n",
"Session.send = _send"
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