Crash when sending using websocket when gateways have been deleted.

[g...@amplex.dk]

Hi!

Lorawan-server 0.7.0.

I ran into a strange problem. When sending a multicast downlink to my nodes I got a crash, where the websocket would terminate. I found out that the reason was that I had deleted some of my gateways. The frames log showed that the message was sent to those gateways too. I expect a hidden 404 error inside the lorawan-server causing the crash. Anyway by creating the gateways again the error disappeared.

Looks like a bug to me. Maybe someone skilled in Erlang could take a look at it? 

2020-12-18 09:39:00.806 [debug] <0.1552.0>@lorawan_connector_ws:terminate:187 WebSocket terminated: {crash,error,{badmatch,[]}}

2020-12-18 09:39:00.806 [error] <0.1552.0> CRASH REPORT Process <0.1552.0> with 0 neighbours crashed with reason: {{badmatch,[]},[]}

2020-12-18 09:39:00.806 [error] <0.1552.0> Ranch listener http terminated with reason: {{badmatch,[]},[]}

2020-12-18 09:39:00 =CRASH REPORT====

  crasher:

    initial call: cowboy_clear:connection_process/5

    pid: <0.1552.0>

    registered_name: []

    exception error: no match of right hand side value []

    ancestors: [<0.380.0>,<0.379.0>,ranch_sup,<0.248.0>]

    message_queue_len: 0

    messages: []

    links: [<0.380.0>,#Port<0.411>]

    dictionary: []

    trap_exit: true

    status: running

    heap_size: 6772

    stack_size: 28

    reductions: 24271

  neighbours:

2020-12-18 09:39:00 =ERROR REPORT====

Ranch listener http had connection process started with cowboy_clear:start_link/4 at <0.1552.0> exit with reason: {{badmatch,[]},[]}

/Gert