Build Pipeline On BitBucket For Flutter Project

I have created pipelines for my android projects on bitbucket which are built great! I am trying to do the same for my flutter project! The first time i uploaded it in the bitbucket the project was built perfectly and the artifact was installed and played as well!

From the second time and then i get an error which i cannot understand! (i havent changed something in the project neither on the build gradle nor the .yml on the bitbucket.

This is the error i am getting:

    FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:checkReleaseAarMetadata'.
> 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: /root/.gradle/caches/transforms-2/files-2.1/82304f0dc7152d4b977a2625d27b0c35/jetified-window-java-1.0.0-beta04/META-INF/com/android/build/gradle/aar-metadata.properties.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 4m 15s
Running Gradle task 'assembleRelease'...                          255.9s
Gradle task assembleRelease failed with exit code 1

and this is my bitbucket .yml

image: cirrusci/flutter

options:
  size: 2x
  
pipelines:
  default:
     - step:
          name: IMON
          deployment: Test
          caches:
            - gradle
          size: 2x
          script:
            - echo 'Start Building'
            - flutter clean
            - flutter build apk
            - echo 'Building Finished'
          artifacts:
            -  build/app/outputs/flutter-apk/**

and this is my 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"
apply plugin: 'com.google.gms.google-services'

def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

android {
    compileSdkVersion 30

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

    lintOptions {
        disable 'InvalidPackage'
        checkReleaseBuilds false
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "example.project.flutter"
        minSdkVersion 25
        targetSdkVersion 30
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

    signingConfigs {
//        release {
//            keyAlias keystoreProperties['keyAlias']
//            keyPassword keystoreProperties['keyPassword']
//            storeFile file(keystoreProperties['storeFile'])
//            storePassword keystoreProperties['storePassword']
////            storeFile file("key.jks")
//
//        }
    }

    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
//            signingConfig signingConfigs.release
            minifyEnabled true
            shrinkResources false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.core:core:1.3.1'
    implementation 'com.google.firebase:firebase-messaging:21.0.1'
    implementation 'com.google.firebase:firebase-analytics:18.0.3'
    implementation 'com.android.support:multidex:1.0.3'
    implementation("com.google.android.gms:play-services-fitness:20.0.0")
    implementation("com.google.android.gms:play-services-auth:19.0.0")
}

Please keep in mind that i dont want to put my sdkversion at 31! i want to keep it at 30. I dont understand why the first time it worked and not all the other times. Can you please help me?

Sounds like you have an dependency with SDK with level 31, but on your project are using SDK with level 30. You can:

1. find dependency that use 31 level of SDK and downgrade it;
2. set 31 level of SDK for your project.

For second solution it could be similar like this:

android {
    compileSdkVersion 31

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

    lintOptions {
        disable 'InvalidPackage'
        checkReleaseBuilds false
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "example.project.flutter"
        minSdkVersion 25
        targetSdkVersion 31
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }
    // ...
}