Client creates a new connection when it reconnects to one of the namespaces.

[aperfilyev]

Describe the bug Let's imagine that we open two sockets to the same path but with different namespaces. Here we see only one connection with the multiplex. Everything is OK. Next, we will disconnect from one of the sockets, and after some time we will open it again. I expect no new connection will be created.

To Reproduce

Socket.IO java client version: 1.x

Client

@Test
public void namespacesTest() throws Exception {
    IO.Options opts = new IO.Options();
    opts.forceNew = false;
    opts.path = "/path";
    Socket socket1 = IO.socket(uri() + "/nsp1", opts);
    Socket socket2 = IO.socket(uri() + "/nsp2", opts);
    socket1.open();
    socket2.open();
    
    assertThat(socket1.io(), equalTo(socket2.io())); // passes as expected
    socket2.close();
    
    Socket socket3 = IO.socket(uri() + "/nsp2", opts);
    socket3.open();
    
    assertThat(socket1.io(), equalTo(socket3.io())); // fails as not expected
    
    socket1.close();
    socket3.close();
}

Expected behavior

Single connection is reused

[momocow]

Just found something in the document, it might give you some clues of the behavior.

Please note that multiplexing will be disabled in the following cases:

• multiple creation for the same namespace

const socket1 = io();
const socket2 = io(); // no multiplexing, two distinct WebSocket connections

https://socket.io/docs/v4/namespaces/#client-initialization

It says "multiple creation" regardless of connection state, opened or closed.