fix(client): discard timed-out packets from the Engine.IO buffer - #5560
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dyk1454683243-sudo wants to merge 1 commit into
Open
dyk1454683243-sudo wants to merge 1 commit into
dyk1454683243-sudo wants to merge 1 commit into
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When an acknowledgement times out, Socket.IO already drops the packet from its own send buffer. If the socket is still considered connected, the event has already been written to the Engine.IO write buffer and was later flushed once the transport became writable again. Remove those unflushed Engine.IO packets on timeout, but keep a multi-packet payload intact if any fragment was already handed to the transport. Fixes socketio#4318 Co-authored-by: David <dyk1454683243-sudo@users.noreply.github.com>
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The kind of change this PR does introduce
Current behavior
An event emitted with
timeout()while the connection is still considered open can already be sitting in the Engine.IO write buffer (transport temporarily unwritable, for example after a network disruption that has not closed the socket yet).When the acknowledgement times out, Socket.IO removes the packet from its own
sendBuffer, but the encoded Engine.IO packet remains queued. Restoring the network / making the transport writable again flushes that timed-out event to the server.This is #4318.
New behavior
On acknowledgement timeout the client also removes every Engine.IO packet created from that Socket.IO event, as long as none of them has been handed to the transport yet.
If any encoded packet is already part of the current flush batch, all related packets are left intact so a binary event cannot be partially transmitted.
Neighboring in-flight events are still flushed normally.
Other information (e.g. related issues)
Fixes #4318.
Regression coverage: