Hello. I am owner of <TelegramBotAPI library> and ...

# serialization

[Ovsyannikov Alexey]

Hello. I am owner of TelegramBotAPI library and currently I am working on a new update related to new Kotlin and other dependencies versions. I have faced with an issue after upgrade of my project up to Kotlin 1.4.0 and Serialization up to 1.0.0-RC. It is look like currently code for JS serializer is generating incorrectly due to the fact that the test which normally must correctly work is failing. I have created a small bot for that and found the things you will see in attached screenshot. In two words: tmp0_subject was set up from this._file_3 on line 98291 on screenshot. This value is absent, but there is value value._file_3 which is look like something what must be on place of tmp0_subject

[Ovsyannikov Alexey]

Also I have created small test which is failing with the same error: https://github.com/InsanusMokrassar/TelegramBotAPI/blob/0.28.0/TelegramBotAPI-core/src/commonTest/kotlin/com/github/insanusmokrassar/TelegramBotAPI/SimpleInputFilesTest.kt

[Ovsyannikov Alexey]

I have launched test from previous message and capture screenshot with the same (or at least similar): we have calling of this.file which is absent, but target value is stored in in value.file_gskrkt$_0 field

[bashor]

Simplified example:

import kotlinx.serialization.*
import kotlinx.serialization.json.Json

@Serializable
class A(val prop: String) {
    val prop2: String = when(prop) {
        "aaa" -> "222"
        else -> {
            println("AAA") // Side effect
            "333"
        }
    }
    val prop3 = prop.length // unexpected TypeError
}

fun test() {
    val a = A("aaa")
    println(JSON.stringify(a))
    println(Json.encodeToString(a))
}

fun main() {
    test()
}

On both JS BEs it leads to crash with TypeError while serializing. I didn’t check it on other BEs.
Also, it looks strange to observe side effects from prop2 initializer during serialization, is it intended?

cc @sandwwraith @Vsevolod Tolstopyatov [JB]

[bashor]

In the original code it was NoWhenBranchMatchedException, but root of a problem is the same as in the simplified version.

[Vsevolod Tolstopyatov [JB]]

Thanks, filed https://github.com/Kotlin/kotlinx.serialization/issues/1004

[bashor]

@Vsevolod Tolstopyatov [JB] what about second part?

Also, it looks strange to observe side effects from prop2 initializer during serialization, is it intended?