Hi everyone, I’m sorry if this has been discussed already somewhere. I’m trying to get the benefit of the

ThrowsCount

rule. I have a violated code here:

private fun ensureScanningIsPossible() {
    if (!isDiscoveryPermissionGranted) {
        throw DiscoveryErrors.DiscoveryPermissionsMissingError(neededDiscoveryPermissions)
    } else if (isDiscoveryOngoing) {
        throw DiscoveryErrors.DiscoveryAlreadyStarted
    } else if (!isBluetoothAvailable()) {
        throw DiscoveryErrors.BluetoothDisabledError
    } // More to come later...
}

Why is this discouraged? The doc said: “Functions should have clear 

throw

 statements”. How can we achieve a “clear” version? I tried to refactor by using nullable type but I feel a bit skeptical about the new code:

private fun ensureScanningIsPossible() {
    val error: DiscoveryErrors? = when {
        !isDiscoveryPermissionGranted -> DiscoveryErrors.DiscoveryPermissionsMissingError(neededDiscoveryPermissions)
        isDiscoveryOngoing -> DiscoveryErrors.DiscoveryAlreadyStarted
        !isBluetoothAvailable() -> DiscoveryErrors.BluetoothDisabledError
        else -> null
    }
    error?.let { throw it }
}

To give you a general answer, exceptions are generally discouraged in Kotlin. This goes along with the

ThrowsCount

rule that should limit the usages of the

throw

keyword (and so reducing usages of exceptions). In your specific case, the first snippet you posted is definitely better than the second and you should probably just suppress the rule violation for your function.

@thuytrinh can u paste ur detekt config ThrowsCount here

That’s the exact config I’m using. The default one.

just to reproduce ur issue i added like below and detekt found this

i believe the ThrowsCount is activated

Right. I’m aware of it. Just wanna understand the benefit of it as well as how to refactor

style - 10min debt ThrowsCount - [ensureScanningIsPossible] at