Why doesn't my println statement get hit? ```val ...

# getting-started

[Colton Idle]

Why doesn't my println statement get hit?

val supabase = createSupabaseClient(
    supabaseUrl = "",
    supabaseKey = ""
) {
    install(Auth)
    println("SUPABASE INIT")
}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            
        }
    }
}

[Colton Idle]

If I update to

setContent {
        supabase    
}

then it will print. It's as if createSupabaseClient is acting lazy... but it shouldn't be.

[Joffrey]

what's createSupabaseClient?

[Colton Idle]

inline fun createSupabaseClient(supabaseUrl: String, supabaseKey: String, builder: SupabaseClientBuilder.() -> Unit) = SupabaseClientBuilder(supabaseUrl, supabaseKey).apply(builder).build()

[Joffrey]

Is the val supabase declaration actually in the same file?

[Colton Idle]

no

[Colton Idle]

I'm trying to get the github reference to it. since its open source code

[Colton Idle]

1 sec

[Joffrey]

If it's a top-level variable, it won't be initialized until the class that represents your file is loaded, and that won't happen until you use something from the file

[Colton Idle]

🤔

[Joffrey]

So createSupabaseClient is not lazy, but the initialization of val supabase as a whole is

[Colton Idle]

here's the full convo https://kotlinlang.slack.com/archives/C06QXPC7064/p1726801984414839

this behavior seems to be surprising the maintainer. 😄

[Joffrey]

If you add another variable in the same file as val supabase, and reference that other unrelated variable instead from setContent you will probably see your print too

[Colton Idle]

oh

[Colton Idle]

sorry

[Colton Idle]

I misread your question

[Colton Idle]

Is the val supabase declaration actually in the same file? (edited)

Yes. It is in the same file

[Joffrey]

I meant is the val supabase declaration in the same file as your activity?

[Colton Idle]

package com.example.supabase1

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import com.example.supabase1.ui.theme.Supabase1Theme
import io.github.jan.supabase.auth.Auth
import io.github.jan.supabase.createSupabaseClient

val supabase = createSupabaseClient(
    supabaseUrl = "",
    supabaseKey = ""
) {
    install(Auth)
    println("SUPABASE INIT")
}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Supabase1Theme {
            }
        }
    }
}

[Colton Idle]

Yes

[Joffrey]

Oh ok

[Colton Idle]

im just trying supabase. and in my suppppper simple app. im not seeing it init. and i was confused. so i asked in #C06QXPC7064 but yeah. the author also seems perplexed.

not sure if this is a bug somewhere in kotlin, or if Im just missing something basic. lol

[Joffrey]

Oh wait. It doesn't matter if it's in the same file. It matters if it's in the same class. And it's not

[Joffrey]

So basically your above code compiles to 2 classes. One is NameOfFileKt and the other is MainActivity. If nothing from NameOfFileKt is used (meaning no top-level property or function from your file), then it won't be initialized

[Colton Idle]

interesting

[Colton Idle]

do you know why this works?

[Colton Idle]

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Log.e("XYZ", "")
        setContent {
            Supabase1Theme {
                buildString
            }
        }
    }
}

val supabase = createSupabaseClient(
    supabaseUrl = "",
    supabaseKey = ""
) {
    install(Auth)
    println("SUPABASE INIT")
}

val buildString = buildString {
    println("buildstring INIT")
    append("hello world")
}

[Colton Idle]

the above ^ prints both printlns. Even though I never call supabase

[Joffrey]

Yes, that's what I told you above, as soon as you use a single thing from the top level declarations, the class that represents the file is loaded, and thus all non-lazy properties are initialized

[Colton Idle]

okay. very interesting.

[Colton Idle]

i learned something new.

[Colton Idle]

so basically everything outside of

class MainActivity : ComponentActivity() {

is a different file techncially

[Colton Idle]

@Jan if you're curious ^

[Joffrey]

Sort of. Rather a different class. All top-level properties and functions in Kotlin actually end up in an implicit class named after the file, but all type declarations are their own classes.

[Joffrey]

And the second piece of the puzzle is that, on the JVM, class loading is lazy; but when a class loads, it's entirely initialized.

[Colton Idle]

gotcha. i wonder if the same thing would happen in java

[Joffrey]

Java doesn't have top-level declarations, that's why Kotlin generates a class to make the JVM happy 🙂

[Colton Idle]

or. i guess I wouldn't be able to declare a variable outside of a class in java

[Colton Idle]

gotcha

[Colton Idle]

okay.

[Colton Idle]

To drive the point home I did this

package com.example.supabase1

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import com.example.supabase1.ui.theme.Supabase1Theme

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Supabase1Theme {
            }
        }
    }
}

and then another file Blah.kt

package com.example.supabase1.ui

import io.github.jan.supabase.auth.Auth
import io.github.jan.supabase.createSupabaseClient

val supabase = createSupabaseClient(
    supabaseUrl = "",
    supabaseKey = ""
) {
    install(Auth)
    println("SUPABASE INIT")
}

val built = buildString {
    println("buildstring INIT")
    append("hello world")
}

and in this case. it makes sense to me why built or supabase aren't init'd

[Joffrey]

Yeah for Kotlin this is the same situation as before

[Joffrey]

And if you do:

package com.example.supabase1

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import com.example.supabase1.ui.theme.Supabase1Theme
import io.github.jan.supabase.auth.Auth
import io.github.jan.supabase.createSupabaseClient


class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Supabase1Theme {
            }
        }
    }
}

object MyOtherClass {
    val supabase = createSupabaseClient(
        supabaseUrl = "",
        supabaseKey = ""
    ) {
        install(Auth)
        println("SUPABASE INIT")
    }

    val built = buildString {
        println("buildstring INIT")
        append("hello world")
    }
}

It's also the same, modulo the class names of course

[Colton Idle]

alright. last question.

package com.example.supabase1

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import com.example.supabase1.ui.theme.Supabase1Theme
import io.github.jan.supabase.auth.Auth
import io.github.jan.supabase.createSupabaseClient

val supabase = createSupabaseClient(
    supabaseUrl = "",
    supabaseKey = ""
) {
    install(Auth)
    println("SUPABASE INIT")
}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Supabase1Theme {
            }
        }
    }
}

If I have the above... is there any easy way to load the supabase variable containing class without calling it in MainActivity?

[Colton Idle]

like. i want createSupabaseClient to be called. but I don't want to call supabase in my MainActivity code

[Colton Idle]

I know that might be a stupid request. but im trying to see if theres some way i can make sure the other class gets loaded without having to call it specifically

[Joffrey]

Mmmh I struggle to understand the use case. Who will be the consumer of the side effect? Because at the moment you access stuff from the side effect, you probably would need the supabase variable, right?

[Colton Idle]

I guess i just want the app to have the auth already loading for the MainActivity

[Colton Idle]

So I would probably just do the "right thing" and create an Application class and call the supabase initialization there.

[Joffrey]

Ah I see. Unfortunately I haven't done Android dev in a very very long time, so I don't know the best practices for things that you want to initialize globally.

[Joffrey]

Is it just for performance or for correctness? From the initial thread it seemed like you were getting a null session or something. If it's for correctness maybe the library could be designed differently, so you cannot get a null session if there is one that's loading. Maybe a suspend client creation that would only finish when the session is loaded or something. (I really don't have domain knowledge, so I might be speaking nonsense)

[Jan]

So createSupabaseClient is not lazy, but the initialization of val supabase as a whole is

Yea that makes sense, forgot that top level Kotlin declarations work like that.

I guess i just want the app to have the auth already loading for the MainActivity

You could really just do something simple like this:

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Supabase1Theme {
                   var loaded by remember { mutableStateOf(false) }
                   LaunchedEffect(Unit) {
                           supabase.auth.awaitInitialization()
                           loaded = true
                   }
                   if (loaded) {
                       //App
                   } else {
                       CircularProgressIndicator()
                   }
            }
        }
    }
}

Or use the sessionStatus state flow as described in the other thread. What is to note here that initialization/loading doesn't only mean to read the session data from the FS. The data gets read and then maybe the session has to be refreshed (API call) and only after that the session is available in the SupabaseClient. The refresh operation can also fail due to e.g. network problems, so you have to also handle that. (Everything reflected in the sessionStatus API)

[Colton Idle]

Yeah. I mean. I think normally this is a non-issue. it was more breaking my brain because i wasn't sure how I got into this sort of scenario.

[Colton Idle]

anyway. thanks everyone for teaching. now that i think about it. i think i had this same exact issue in a ktor server app because i had a db connection declared outside of the main app. and i ended having to have my first line of my ktor server just be db so that it would init the db that was outside of that class.

[Colton Idle]

phew. okay. always learning 💪

Thanks everyone for teaching!

[Joffrey]

Happy to help! Usually these things are non-issues (and rather desirable) because you won't face initialization issues unless you access something, but if you do access it then it will be initialized first 😄

[Colton Idle]

exactly. so even though the example was contrived. it did legitimately throw me in a loop as to why my supabase auth code wasn't running.

[Joffrey]

Fair enough 🙂