Crash in `SSHChildChannel` about swift-nio-ssh HOT 4 CLOSED

Ok great, this crash report is sufficient. I think the issue here is that we don't change that self.state.sentClose is false before we send the window update. That would likely fix the issue here. It shouldn't be too hard to construct a unit test that triggers this.

from swift-nio-ssh.

Hmm, I'm not observing this crash locally. Can you attach a full backtrace, or even better a crash report?

from swift-nio-ssh.

NIOSSHClient-2023-04-17-164811.ips.zip

You can try to reduce the time before closing:

DispatchQueue.global(qos: .default).asyncAfter(deadline: .now() + 0.5) {
    print("❌")
    _ = childChannel.close(promise: nil)
}

I propose a new version (I think the print was creating some delay).

from swift-nio-ssh.

I tried a fix. I am not super sure about it:

• Triggering the right action after an event, based on the current state, seems to be the responsibility of the state machine rather the SSHChildChannel directly. Should the action be propagated to the state machine and handled by it?
• As the window seems to be used from one message reception to the other, if the server keeps sending messages while the client is closed and does not trigger the appropriate window update, could it lead to unpredictable behaviors? I am not a ssh expert.

Let me know. Thanks for your time!

from swift-nio-ssh.