Socket.io-client: v3 disconnection of socket seems to close underlying connection.

[david-fong]

You want to:

• [x] report a bug
• [ ] request a feature

Current behaviour

After I upgraded to v3, when I call socket.disconnect() on either of the client or server sides, it seems that the Manager's underlying connection is also being closed- all other sockets using the same manager / underlying connection also get disconnected.

I don't know where to file this issue. Maybe it has root in engine.io v4?

Here's a diff of my project during the upgrade. I apologize that it contains some unrelated changes as well. The main thing I mean to highlight is that I didn't make any changes to how I setup and manage connections (you can cmd+F for "disconnect", "close", "io.socket").

Steps to reproduce (if the current behaviour is a bug)

Please see this jsfiddle.

Expected behaviour

The v2 behaviour is that calling socket.close() on the clientside and on the serverside should only close that socket when a manager has multiple namespaces- it should not close every multiplexed socket under that socket's manger.

Setup

• OS: Windows 10
• browser: Chrome 86.0
• socket.io version: 3.0.0

Observe behaviour difference when using socket.io v2 instead.

Other information (e.g. stacktraces, related issues, suggestions how to fix)

[david-fong]

I spent a bunch of time debugging my own code thinking I broke something :')

Looking forward to the fix! And thanks again for your hard work in starting v3.

[alextenev]

The "connecting" event is never fired on socket connection and doesn't fill the connecting array in manager:
https://github.com/socketio/socket.io-client/blame/master/lib/manager.ts#L599

When _destroy is called if (this.connecting.length) return; this._close(); will always close the connection.

I don't see an issue in the client code. Maybe some bug on server side? In the server code I couldn't find any event named "connecting". Maybe that's the issue?

Here is the commit that removes the emit of "connecting".

https://github.com/socketio/socket.io-client/commit/b60e909039d4bbb979d32ec86ac16c5398526b44#diff-f0e64910289a49966c99ceadaa5637404e3439ec0812a4bdb7003fe1e5a33d1c

@darrachequesne Could you please check this issue.

[darrachequesne]

@david-fong I could indeed reproduce the issue, thanks a lot for the detailed steps :+1:

[darrachequesne]

This should be fixed by https://github.com/socketio/socket.io-client/commit/f8f60fc860f51aa6465fc32dd9275a8e1d22f05d (included in [email protected]).

Again, thanks for the detailed report, that really helps!