If i start a coroutine with CoroutineScope inside ViewModel

Question

If i start a coroutine with CoroutineScope inside ViewModel which is doing some db operation but this operation doesn t return anything So coroutine starts performs db operation and completes During this operation if my viewmodel onCleared is called but i don t cancel coroutine will my viewmodel leak

octylFractal · Answer

if you use the view model scope it automatically cancels all jobs iirc

Anastasia Finogenova · Answer

Kenzie is right the answer depends on the scope you use but unless canceling or using viewModel scope it will

streetsofboston · Answer

How can we use CoroutineScopes in Kotlin by Anton Spaans <https link medium com yEGedqvlg1>

Khan · Answer

Thanks for the answers I know about viewmodel scope But i just wanna make sure what i have asked above

Khan · Answer

``` CoroutineScope launch <http Dispatchers IO|Dispatchers IO> Something ``` If i start coroutine like this in viewmodel If viewmodel is cleared but coroutine is not cancelled will my viewmodel leak If it s not finishing the job before the ViewModel gets cleared then the ViewModel can t be garbage collected and a leak will occur Got this statement from someone

streetsofboston · Answer

When a CoroutineScope ends canceled finished normally or through an exception all it s child Coroutines will be canceled There is no need to keep track of all the `Job`s and `Deferred`s and cancel them individually

streetsofboston · Answer

Note that a Coroutine can only be properly canceled when it is suspending i e a `suspend fun` was called and is currently suspending A Coroutine that is still actively running or blocking won t get magically canceled Also you can call `isActive` in your normal non suspending parts of the code in your Coroutine to exit tight loops or skip long lasting blocking parts of your code

Khan · Answer

Yes i understand that But i am asking about this speciifc case where i don t have any child Its only one coroutine which is created from viewmodel If viewmodel on cleared is called and we don t cancel coroutine will it cause a leak

streetsofboston · Answer

You create Coroutine by calling `viewModelScope launch` or `viewModelScope async` When the `viewModelScope` gets canceled in the `onCleared` of the ViewModel all your Coroutines s launched that way will be canceled as well and nothing leaks unless your Coroutines are blocking and never suspending

streetsofboston · Answer

If you use another `CoroutineScope` instance not `viewModelScope` but one you created yourself eg `CoroutineScope Job ` then you are correct and you may have a leak