Hi, my coroutine job immediately gets cancelled even before staring. Now I am not sure what could be reasons for this. What could be reasons for coroutine to get cancelled even before it is cancelled

private fun CoroutineScope?.launchWithNullCheck(
        block: suspend () -> Unit
    ) {
        this?.let {
            Log.d("FUI", "Scope not null")
            val job = launch {
                Log.d("FUI", "executing block not null")
                block()
            }
            Log.d("FUI", "job isActive ${job.isActive}, isCompleted: ${job.isCompleted}, isCancelled: ${job.isCancelled}")
        }
}

One possible reason is if the

CoroutineScope

that you’re launching it in contains an already-cancelled

Job

. Launching a job as a child of a cancelled job will immediately return a cancelled job and won’t start the coroutine. Hard to say if that’s what’s happening here, though. Can you give any more information about how it’s behaving? Do you see any output, for example?

Launching a job as a child of a cancelled job will immediately return a cancelled job

Let me verify this and give more information

this?.coroutineContext?.job

should work (where

this

is the coroutine scope receiver from your example)

I printed out whether scope is active or not and existing job is Cancelled or not

private fun CoroutineScope?.launchWithNullCheck(
        block: suspend () -> Unit
    ) {
        this?.let {
            Log.d("FUI", "scope isActive: ${this.isActive}")
            Log.d("FUI", "existing job cancelled: ${coroutineContext.job.isCancelled}")
            Log.d("FUI", "Scope not null")
            val job = launch {
                Log.d("FUI", "executing block not null")
                block()
            }
            Log.d("FUI", "job isActive ${job.isActive}, isCompleted: ${job.isCompleted}, isCancelled: ${job.isCancelled}")
        }
}

For me it says job was not cancelled but scope became inactive

Okay, that explains why the job does not start. The scope’s job is already finished, so it can’t launch new child jobs. If it’s not active, but not cancelled, that means it just completed normally. How did you create this scope?

I passed this scope from another class android's viewmodel This is actually

viewmodelscope

and I am holding reference to that in this class

In that case I guess it just means that the associated

ViewModel

has already been cleared?

Thats the issue, Its not cleared. This happens while the viewmodel is active

Okay, I haven’t used

ViewModelScope

myself so I’m not sure know what could cause it to be inactive. Hopefully someone with more Android knowledge can help 🤞

I figured it out. Instead of passing

viewModelScope

I was passing its childScope which caused the issue ChildScope was getting completed before my further operations Passing viewModelScope solved the issue