Race condition when closing both server and client at the same time

[yyewolf]

We had a weird issue with test not working from time to time, turns out there's a race condition if you close both a server and a client at the same time.

Take this example :

client.Close()
server.Stop()

In this case, the goroutine might close the client channel, but receive the server closed message first, meaning that it would try to send to the closed channel.

[vjeantet]

This race condition has been fixed in commit f367b2e ("Fix WaitGroup data race in shutdown-listener goroutine").

The shutdown-listener goroutine no longer uses wg.Add/Done — it now uses a dedicated shutdownDone channel, and close() waits on it before calling wg.Wait(), which eliminates the race between concurrent server and client shutdown.

Thanks for reporting the issue.