Why is there no retain(nc) in the natsLibevent_Attach() function, and then a corresponding decrement in natsLibevent_Detach()?

[yanyongcheng]

Observed behavior

Why is there no retain(nc) in the natsLibevent_Attach function, and then a corresponding decrement in natsLibevent_Detach()?
Instead, the retain(nc) is done in natsConnection_ProcessReadEvent(). What's the purpose? and it doesn't feel very intuitive.

Expected behavior

retain(nc) in the natsLibevent_Attach function, and then a corresponding decrement in natsLibevent_Detach()

Server and client version

client:3.10.1

Host environment

No response

Steps to reproduce

No response

[yanyongcheng]

@kozlovic in this function below,(conn.c)

static void
_close(natsConnection *nc, natsConnStatus status, bool fromPublicClose, bool doCBs)
{
...
    if (nc->el.attached)
    {
        nc->el.attached = false;
        detach = true;
        _retain(nc);<==============================is this needed? because you have modified that it has beed retained in Libevent_Attach function.
    }

    natsConn_unlockAndRelease(nc);

    if (detach)
    {
        nc->opts->evCbs.detach(nc->el.data);
        natsConn_release(nc);<==========================is this needed? Because it will be released in Detach function.
    }
...
}

[kozlovic]

@yanyongcheng I decided to keep it at the time, but will likely remove in a next PR. I also need to update the adapters since I spotted an issue in a specific case.

[yanyongcheng]

@kozlovic
Hi, the Libevent Detach funcion should call natsConn_release(),not natConnection_Destroy()? Because the natsConnection_Destroy() will call the _close() again. and the natsConnection_Destroy() should be called by the programmer manually , shouldn't be called automatically in NATA.C Lib?( This is how I understand it, but I'm not sure if my understanding is correct. )

[kozlovic]

@yanyongcheng No, I don't want to export the release function. Calling natsConnection_Destroy() will have the same effect since the first _close() will change the status to closed, so the second call will return early (see the check for isClosed) and so we will fall back to calling natsConn_release() inside the natsConnection_Destroy().