Lint considers Kotlin MutableMap.forEach() as java.util.Map.forEach()

Question

I am using Kotlin's MutableMap in my Android project. And trying to do some action per item. So here is my code.

private val uris: MutableMap<String, Uri> = mutableMapOf()
// ... Fill the items here ...
uris.forEach {
    val ref = FirebaseFirestore.getInstanse().reference
    uploadFile(ref, it.value)
}

Everything just works fine at runtime, but my CI build fails with below lint error:

MyActivity.kt:142: Error: Call requires API level 24 (current min is 16): java.util.Map#forEach [NewApi]
              uris.forEach {
                   ~~~~~~~

I know we can't use JDK-8's Map for Android projects until the min sdk is 24. But why lint is considering it as JDK-8's Map?

For further information I tried getting the Java code from Kotlin Bytecode option in AS and found that forEach is replaced with while loop and iterator as expected.

So what could be reason and how to solve this? Any lead will be appreciated.

Do you have the Kotlin standard library in your dependencies? — zsmb13, Jan 25 '18 at 08:59
In the code sample map's name is `uris`, while in the error message it's `shopIcons`. Are you sure you're looking in the right place? — Alex Filatov, Jan 25 '18 at 09:08
Possible duplicate of [Kotlin Extension Functions suddenly require api level 24](https://stackoverflow.com/questions/44751469/kotlin-extension-functions-suddenly-require-api-level-24) — MJakhongir, Jan 25 '18 at 09:33
@AlexFilatov, thats my mistake. It was a copy paste problem. Fixed it now. — Chandra Sekhar, Jan 25 '18 at 10:39
Lint __should__ resolve the method used the same way as the IDE's editor and the compiler does though. @ChandraSekhar if you navigate to the declaration of the `forEach` you're using, does it go to the Kotlin one as it should? — zsmb13, Jan 25 '18 at 10:50

score 11 · Accepted Answer · answered Jan 25 '18 at 07:46

11

There are two overloaded foreachs on Map:

Kotlin one:

uris.forEach { (key, value) -> // Do some Action }

Java8 one:

uris.forEach { key, value -> // Do some Action }

Confusing, isn't it?

answered Jan 25 '18 at 07:46

voddan

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I am using uris.forEach(action: (Map.Entry) -> Unit) one – Chandra Sekhar Jan 25 '18 at 07:50
Okay, so what now? I'm using data.forEach { /* Do something with 'it' */ } and is complaining. – Damia Fuentes Aug 03 '21 at 16:06

score 2 · Answer 2 · answered Jan 25 '18 at 07:39

2

I think this is an import problem. Maybe you have used JDK 8's Map.forEach.

You have to use kotlin.collections.MutableMap.forEach

You can also check this blog:

http://blog.danlew.net/2017/03/16/kotlin-puzzler-whose-line-is-it-anyways/

answered Jan 25 '18 at 07:39

Avijit Karmakar

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Looks interesting. But my import statements has none of those. – Chandra Sekhar Jan 25 '18 at 07:52

gildor · Answer 3 · 2018-01-25T08:44:35.630

0

Are you sure that you use forEach from Kotlin? Because there are two forEach, one from Kotlin with Map.Entry as an argument and one from Java with two arguments: key and value. Please, show full version of your code. If you use forEach without arguments, it means that you use Kotlin one (you have it implicit argument).

If you use Kotlin forEach and still have this warning you should report this issue to Android Issue Tracker

edited Jan 25 '18 at 08:44

answered Jan 25 '18 at 07:33

gildor

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@ChandraSekhar You use Kotlin version of forEach, so it's lint bug. Suppress this warning in Lint and report an issue to Android tracker – gildor Jan 25 '18 at 08:44

Lint considers Kotlin MutableMap.forEach() as java.util.Map.forEach()

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