```var webSocketSession = DefaultClientWebSocketSe...

# coroutines

[ursus]

var webSocketSession = DefaultClientWebSocketSession? = null
try {
      webSocketSession = ktorClient.webSocketSession(url)
      ....
} finally {
      webSocketSession?.close() <----
}

Coroutines general question:
ktor calls close in finally block as to do graceful exit.

However close is a suspend function.
How can it work reliably? Aren't all suspend functions no-op after cancellation unless wrapped with NomCancellable ?

Am I missing something?

[rkechols]

https://kotlinlang.org/docs/cancellation-and-timeouts.html#closing-resources-with-finally

My understanding is that using launch to start a new coroutine in a scope that's been cancelled will do nothing, but you can still always call suspend functions and it's just part of the current control flow.

I could be totally wrong though

[ursus]

not sure what you mean

[ursus]

im debugging it, control flow enters close, but doesnt do anything, as send(close frame) will throw; that exception is then eaten, so basically its a big no-op
so I've no idea what do the authors meant by it

[rkechols]

Well if you know that webSocketSession is not null but its close method is indeed not being called, it indeed may be that further calls to suspend functions don't work at all once the scope is cancelled.

In that case, the finally block would be more relevant in the case of normal termination with no exception or for any exception other than a cancellation.

[ursus]

if it were designed to be a graceful termination, why put it in finally block?
In that case it should look more like

webSocketSession.stuff()
webSocketSession.close()

which makes me think im missing something

[CLOVIS]

> Aren't all suspend functions no-op after cancellation unless wrapped with NomCancellable ?
After cancellation yes, but a non-cancellation error could be thrown, in which case it will be closed.

[hantsy]

Kotlin provides`<autoclosable resource>.use {}` to close the resources gracefully like Java try-catch-resources.