I m using `suspendCancellableCoroutine` to suspend a corouti

Question

I m using `suspendCancellableCoroutine` to suspend a coroutine awaiting the results of a callback API to resume the coroutine with ```val result = suspendCancellableCoroutine continuation gt callbackApi continuation resume it ``` This works as expected the first time the code is called but the second time the code is executed `continuation resume ` doesn t work `continuation isActive` is false `continuation isCompleted` and `continuation isCancelled` are true Is it wrong to expect an active continuation after calling `suspendCancellableCoroutine` Even after wrapping the code in `async` launching a fresh coroutine the continuation still isn t active the second time the code executes What am I doing wrong

efemoney · Answer

Check your callback api it might be capturing a stale lambda

efemoney · Answer

Also show the surrounding code and or how callbackApi is implemented

Jeff Lockhart · Answer

I had the same thought so I m logging the other state captured in the lambda to confirm it is the new lambda I m hoping after getting some sleep I ll see something I missed this morning sweat smile I ll share more of the code

Jeff Lockhart · Answer

My code and tests are based on the SQLDelight paging extension The `suspendCancellableCoroutine` is used to suspend awaiting callback The failing tests were all calling If I replace `runTest` with `runBlocking` and the `withPagingDataDiffer` function with this ```suspend fun lt T Any gt PagingData lt T gt withPagingDataDiffer testScope CoroutineScope diffCallback DiffUtil ItemCallback lt T gt block AsyncPagingDataDiffer lt T gt gt Unit val pagingDataDiffer = AsyncPagingDataDiffer diffCallback NoopListCallback mainDispatcher = Dispatchers Default workerDispatcher = Dispatchers Default val job = testScope launch pagingDataDiffer submitData this withPagingDataDiffer delay 100 block pagingDataDiffer job cancel ``` the tests now pass with the continuations behaving as expected

Jeff Lockhart · Answer

Obviously I don t like the arbitrary `delay 100 ` awaiting the database operations to be completed I ll have to see if there s a better way to replace this

Jeff Lockhart · Answer

I created <https github com Kotlin kotlinx coroutines issues 3819|an issue> to track this