Changing the kotlin version results in change in compilesdkversion for some reasons

Question

I cloned a flutter project, and tried to run it on an android device. But I ran into this error:

Execution failed for task ':app:checkDebugAarMetadata'. Multiple task action failures occurred: A failure occurred while executing com.android.build.gradle.internal.tasks.CheckAarMetadataWorkAction > The minCompileSdk (31) specified in a dependency's AAR metadata (META-INF/com/android/build/gradle/aar-metadata.properties) is greater than this module's compileSdkVersion (android-30). Dependency: androidx.window:window-java:1.0.0-beta04. AAR metadata file: C:\Users\Harshit.gradle\caches\transforms-2\files-2.1\ac98fb722099a50563f635966aedbe29\jetified-window-java-1.0.0-beta04\META-INF\com\android\build\gradle\a ar-metadata.properties.

The error mentions that the current compileSdkVersion is 30, but some dependency works only with 31.

So, I just changed compileSdkVersion and targetSdkVersion from 30 to 31, in my app-level build.gradle, then I tried to run it again, and I ran into another error:

Task :location:compileDebugKotlin e: Incompatible classes were found in dependencies. Remove them from the classpath or use '-Xskip-metadata-version-check' to suppress errors e: C:/Users/Harshit/.gradle/caches/transforms-2/files-2.1/1028a8ca100cbb0fda6fd6257a450fc1/jetified-window-1.0.0-beta04-api.jar!/META-INF/window_release.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.5.1, expected version is 1.1.15.

After a quick google search, I found a fix, that I need to mention the latest kotlin version in android/build.gradle file, so I changed this:

ext.kotlin_version = '1.3.50'

to this:

ext.kotlin_version = '1.6.0'

and downloaded the respective kotlin plugin. Then I tried to run the project again, and I ran into this error:

Execution failed for task ':google_maps_flutter:checkDebugUnitTestAarMetadata'. Multiple task action failures occurred: A failure occurred while executing com.android.build.gradle.internal.tasks.CheckAarMetadataWorkAction > The minCompileSdk (31) specified in a dependency's AAR metadata (META-INF/com/android/build/gradle/aar-metadata.properties) is greater than this module's compileSdkVersion (android-29). Dependency: androidx.window:window-java:1.0.0-beta04. AAR metadata file: C:\Users\Harshit.gradle\caches\transforms-2\files-2.1\9d7a6c54f576894d03496d57f9d5a318\jetified-window-java-1.0.0-beta04\META-INF\com\android\build\gradle\a ar-metadata.properties.

This error is identical to the first error, except here it mentions that the current compileSdkVersion is 29, even though I didn't change it after setting it to 31.

So, for some reason, upgrading the version of kotlin results in compileSdkVersin being set to 29 automatically, and I have no idea why.

How can I get rid of this error which says the current compileSdkVersion is 29, even though I have it set to 31?

And why does changing kotlin version tricks it into believing that compileSdkVersion is 29, even though its value is set to 31 in build.gradle?

android/build.gradle:

buildscript {
    ext.kotlin_version = '1.6.0'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:4.1.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:4.3.8'
        
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
    project.evaluationDependsOn(':app')
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

app/build.gradle:

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 31

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.pranshupandya.locus_stalker"
        minSdkVersion 20
        targetSdkVersion 31
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        multiDexEnabled true
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation platform('com.google.firebase:firebase-bom:28.2.0')
    implementation 'com.google.firebase:firebase-analytics'
    def multidex_version = "2.0.1"
    implementation "androidx.multidex:multidex:$multidex_version"
}
apply plugin: 'com.google.gms.google-services'

Answer 1

1. Go to the Project Structure and check your Sdks are rightly mapped to the latest. I had JavaSDK 17 and Android sDK 30

Navigate to your projects build.gradle

Make sure you have these values entered for the compileSdkVersion targetSdkVersion

I had them put same values earlier and the error persisted. So make sure they are one less than the other. In short it should be two different versions.

Answer 2

android {
    compileSdkVersion 31  // update to 31 from 30 

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.ryx.mallties"
        minSdkVersion 21
        targetSdkVersion 31  // update to 31 from 30 
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

Answer 3

1. Try checking the flutter channel using : flutter channel.
2. If it is beta then change to stable version using : flutter channel stable
3. Then flutter clean. flutter pub get and then run the project.

Note : Do not try to modify existing kotlin/java configurations for flutter projects.