Why is the Job passed to context of launch not res...

# coroutines

[Prateek Kumar]

Why is the Job passed to context of launch not respected?

Approach 1:-

viewModelScope.launch(coroutineExceptionHandler) {
    supervisorScope {
        for (i in 0..10) {
            launch {
                delay(i * 1000L)
                throw RuntimeException("abc")
            }
        }
    }
}

Here in Exception Handler all 10 exceptions are recorded.

Approach 2:-

viewModelScope.launch(coroutineExceptionHandler+ SupervisorJob()) {
    for (i in 0..10) {
        launch {
            delay(i * 1000L)
            throw RuntimeException("def")
        }
    }
}

With this only one exception is recorded and rest are cancelled after first exception.

Why is 1 and 2 works differently? Shouldn’t the parent Job used to create child jobs?

[Sam]

launch always creates a new job as the child of the job in its starting context. Passing a job as an argument to the launch function merely replaces its parent job, and is rarely if ever a useful thing to do.

[Prateek Kumar]

If that is the case then a nested launch should override SuperviserJob and just be a normal Job,Right?

_viewModelScope_._launch_(coroutineExceptionHandler) *{*
supervisorScope *{*
for (i in 0..10) {
_launch_ *{*
delay(i * 1000L)
_launch_ *{*
//This scope should not be Supervisor Job but it is
throw RuntimeException("def")
}
}
}
}
}

Above code still collects all the exceptions even though the launch throwing the exception is not directly part of supervisorScope