MQTT lws_callback_on_writeable() issue with libuv backend on 4.5.8

[hbock]

Hi,

Using libwebsockets 4.5.8 with MQTT client and libuv, we see that 9e33c52 partially reverts 6f1026f.

6f1026f fixed an issue we were having with MQTT client, where lws_callback_on_writable(wsi) would not result in the callback event LWS_CALLBACK_MQTT_CLIENT_WRITEABLE if the libuv event loop backend is used.

We have locally reverted 9e33c52 and the behavior is corrected., but we assume that may not be the correct long-term solution. Any advice is helpful.

Thanks!
Harry

[lws-team]

If you reapply 9e33c52, does then applying this help?

diff --git a/lib/roles/mqtt/mqtt.c b/lib/roles/mqtt/mqtt.c
index 50e72429f..2676a8b9a 100644
--- a/lib/roles/mqtt/mqtt.c
+++ b/lib/roles/mqtt/mqtt.c
@@ -1320,7 +1320,6 @@ cmd_completion:
                                wsi->mux.highest_sid = 1;
                                lws_wsi_mux_insert(w, wsi, wsi->mux.highest_sid++);
 
-                               wsi->mux_substream = 1;
                                w->mux_substream = 1;
                                w->client_mux_substream = 1;
                                wsi->client_mux_migrated = 1;

[hbock]

@lws-team yes, if I reapply 9e33c52 and apply this patch, it works great. Thank you! That was incredibly fast.