IllegalStateException : Already resumed

Hi,

I am observing live data using observeForever() and then removing the observer later. I handle success and failure scenarios and resume the continuation object accordingly.

//failure removeObserver(observer) if (coroutine.isActive) coroutine.resume(getErrorState()) //success removeObserver(observer) if (coroutine.isActive) coroutine.resume(data)

In most cases it works fine. However, randomly few times I get exception :

Fatal Exception: java.lang.IllegalStateException: Already resumed, but proposed with update android.widget.RemoteViews@ebbd63d at kotlinx.coroutines.CancellableContinuationImpl.alreadyResumedError(CancellableContinuationImpl.java:277) at kotlinx.coroutines.CancellableContinuationImpl.resumeImpl(CancellableContinuationImpl.java:272) at kotlinx.coroutines.CancellableContinuationImpl.resumeWith(CancellableContinuationImpl.java:189)

It seems , the isActive check isn’t behaving as expected. Please suggest a better check to avoid this crash.

Cheers !

Issue Analytics

State:
Created 3 years ago
Reactions:1
Comments:18 (6 by maintainers)

Top GitHub Comments

4reactions

migmacdevcommented, Oct 6, 2021

Here are my 2 cents, I had the same issue when I wrapped an API callback into a suspendCancellableCoroutine, the callback inside was receiving calls in different methods, therefore cont.resume was being called twice, what I ended up doing was an extension function to only call resume if the cont was active, like:

private fun <T> CancellableContinuation<T>.resumeIfActive(value: T) {
    if(isActive) {
        resume(value)
    }
}

for my case, this works since I only care about the first call to cont.resume

1reaction

psteigercommented, Sep 10, 2021

@aruke a strategy I used to use was to save the continuation in a nullable var, resuming from the var and immediately setting it to null afterwards. Then, if other callbacks eventually try to resume it again, field will be null.

But honestly, it works but it’s flaky design. In my opinion you should only suspend and resume if there’s a single callback that is guaranteed to always run and run exactly once. For example, GMS tasks and addOnCompleteListener.

If you have a code snippet to share I could give further input.

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