connection becomes unusable when switching network while writting

[Roberto Mier Escandon]

Reported:

"Also, when a message fails to send because just that very moment the connection drops, it is not resent when the connection comes back
 I stand corrected. All those messages have been sent succesdfully, i just didnt receive the confirmation. The other side replied but i did not get the messages from him.
 So it loojs like the sending part is fixed, just the receiving still breaks sometimes"

[Roberto Mier Escandon (rmescandon)]

Observed while fixing a reconnection bug [1] that when the network connection drops or switches to another network the socket is not aware of it until passed some seconds. If the socket is used to send any request meanwhile, though the request even can get to destination, the socket becomes useless, so it won't be able to send or receive any more data.

As when this other bug is fixed [2] telegram app will be able to use connectivity api to detect any network disconnection/switch before a socket timeout, and thus, avoid using the socket or even disconnect it while not having connection again.

[1] https://bugs.launchpad.net/bugs/1518300
[2] https://bugs.launchpad.net/bugs/1545673

[Earendil02 (earendil002)]

I have a very critical bug that might be related.
When my phone loses connection for any reason (e.g. weak wifi or mobile signal) telegram disconnects and remains useless even if connection is regained. That is it stops sending and receiving messages even if sometimes notifications arrive. The only workaround is to switch on and off again flight mode, close telegram and reopen it only after the connection is fully restored.
When on a mobile connection there's a sign that connection might ave been compromised when the 'H' symbol of 3G (or 'E' for 2G) is replaced by the 'empty' symbol of wifi connection (even if wifi is turned off). This 9 out of 10 times means that if I open telegram I obtain a blank screen if it was closed, or an useless app (can't send or receive messages) if it was open (background or foreground).
This is a huge problem that seriously compromises usability, especially in zones with poor mobile signal coverage.

[Roman B (roman-bt)]

I have this bug very often and it is quite annoying not to know if a message was sent. I always have to check with the Telegram Web App with slow connections (e.g. when using 2G).