Is this the correct way that the flow is executed?...

# getting-started

[Daniel]

Is this the correct way that the flow is executed?

suspend fun Logout(token: String) {
    val userId = appService.currentUser!!.id       ///// this will execute 1st
    realm.write {                                  ///// this will execute 2nd
        var user = query<UserInfo>("_id = $0", userId).first().find()
        if (user != null) {
            user = findLatest(user)!!.also {
                it.FCMToken.remove(token)
            }
            copyToRealm(user)
        }
    }
    withContext(Dispatchers.Default) {             ///// this will execute 3rd

        realm.syncSession.uploadAllLocalChanges()  ///// this will execute 4rd

        appService.currentUser?.logOut()           ///// this will execute 5th
    }
}

Are they executed in a linear way?

[Stephan Schröder]

to the best of my knowledge derived from tutorials your statements are executed linearly.
In a totally unrelated matter, let's get rid of the not-null-assertion operator !! . Since a logout doesn't make sense, if there isn't a currentUser, let's simply return from the function, should for some strange reason (maybe a race condition 🤷‍♂️) currentUser be null

val userId = appService.currentUser?.id ?: return

let's remove some other issues
• appService.currentUser is invoked twice though it's mutable and might not return the same instance
• there's another !!
• let's replace the var with a val
• the also isn't necessary
• the method starts with a capital letter (this isn't Go, probably you have a codestyle, but I'll "fix" it in my suggestion anyway)
This gives us:

suspend fun logout(token: String) {
    val currentUser = appService.currentUser ?: return
    realm.write {
        query<UserInfo>("_id = $0", currentUser.id).first().find()?.let { user ->
            val latestUser = findLatest(user) ?: run {
                log.warn("strange db inconsistency: findLatest didn't return a user after a user query retrieved an instance from id ${currentUser.id}. defaulting to first found instance")
                user
            }
            latestUser.fcmToken.remove(token)
            copyToRealm(latestUser)
        }
    }
    withContext(Dispatchers.Default) {
        realm.syncSession.uploadAllLocalChanges()
        currentUser.logOut()
    }
}

It's not completely clear if my log.warn is sufficient, or if an exception should be thrown. At least an exception thrown would have more info than the NullPointerException thrown by the initial !! . The exception version would look like this

val latestUser = findLatest(user) ?: error("strange db inconsistency: findLatest didn't return a user after a user query retrieved an instance from id ${currentUser.id}. defaulting to first found instance")