random panic

[SoMuchForSubtlety]

I sometimes get this when trying to connect.
seems to happen randomly, I don't change anything.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x70 pc=0x228b60]

goroutine 28 [running]:
github.com/gorilla/websocket.(*Conn).NextReader(0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
        /home/pi/go/pkg/mod/github.com/gorilla/websocket@v1.4.0/conn.go:938 +0x14
github.com/gorilla/websocket.(*Conn).ReadMessage(0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
        /home/pi/go/pkg/mod/github.com/gorilla/websocket@v1.4.0/conn.go:1028 +0x1c
github.com/Memelabs/dggchat.(*Session).listen(0x20824d0)
        /home/pi/go/pkg/mod/github.com/!memelabs/dggchat@v0.0.0-20171209033102-97642b4d160e/session.go:164 +0x24
created by github.com/Memelabs/dggchat.(*Session).open
        /home/pi/go/pkg/mod/github.com/!memelabs/dggchat@v0.0.0-20171209033102-97642b4d160e/session.go:115 +0xfc

[xDashh]

Iirc there was some race condition with wanting to access the list of connected users before the NAMES message was fully parsed or something along these lines... Try go build -race etc. and you should find it.

[SoMuchForSubtlety]

yea it seems to be a race, I think I cause it by closing the connection very quickly after opening it.

this is the output when I just open the connection and immediately close it.
I get this very consistently

$ go run -race .\main.go
==================
WARNING: DATA RACE
Write at 0x00c000050470 by main goroutine:
  github.com/MemeLabs/dggchat.(*Session).Close()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:138 +0x118
  main.main()
      C:/Users/jakob/Documents/projects/test/main.go:29 +0x486

Previous read at 0x00c000050470 by goroutine 13:
  github.com/MemeLabs/dggchat.(*Session).listen()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:164 +0x63

Goroutine 13 (running) created at:
  github.com/MemeLabs/dggchat.(*Session).open()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:115 +0x219
  github.com/MemeLabs/dggchat.(*Session).Open()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:91 +0xe1
  main.main()
      C:/Users/jakob/Documents/projects/test/main.go:24 +0x426
==================
Found 1 data race(s)
exit status 66

this is the output when I open the connection, send one message and then close it.
I only got this twice, otherwise it ran normally

==================
WARNING: DATA RACE
Read at 0x00c000050470 by goroutine 13:
  github.com/MemeLabs/dggchat.(*Session).listen()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:164 +0x63 

Previous write at 0x00c000050470 by main goroutine:
  github.com/MemeLabs/dggchat.(*Session).Close()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:138 +0x118
  main.main()
      C:/Users/jakob/Documents/projects/test/main.go:36 +0x5ca

Goroutine 13 (running) created at:
  github.com/MemeLabs/dggchat.(*Session).open()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:115 +0x219
  github.com/MemeLabs/dggchat.(*Session).Open()
      C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:91 +0xe1  
  main.main()
      C:/Users/jakob/Documents/projects/test/main.go:26 +0x426
==================
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0x78fc8f]

goroutine 8 [running]:
github.com/gorilla/websocket.(*Conn).NextReader(0x0, 0xc000062b70, 0x46d09c, 0x401d80, 0x1913588, 0x0)
        C:/Users/jakob/go/src/github.com/gorilla/websocket/conn.go:939 +0x4f
github.com/gorilla/websocket.(*Conn).ReadMessage(0x0, 0x6f, 0x2, 0xc0001640a0, 0x2, 0x4, 0x0)
        C:/Users/jakob/go/src/github.com/gorilla/websocket/conn.go:1029 +0x58
github.com/MemeLabs/dggchat.(*Session).listen(0xc0000503c0)
        C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:164 +0x7c
created by github.com/MemeLabs/dggchat.(*Session).open
        C:/Users/jakob/go/src/github.com/MemeLabs/dggchat/session.go:115 +0x21a