flutter firebase app not running on Android: Namespace not specified

I keep getting an error when trying to run on an Android Simulator. I have firebasecore and Square in app payments in this app. This is the error:

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':package_info_plus'.
> Could not create an instance of type com.android.build.api.variant.impl.LibraryVariantBuilderImpl.
   > Namespace not specified. Please specify a namespace in the module's build.gradle file like so:

     android {
         namespace 'com.example.namespace'
     }

     If the package attribute is specified in the source AndroidManifest.xml, it can be migrated automatically to the namespace value in the build.gradle file using the AGP Upgrade Assistant; please refer to https://developer.android.com/studio/build/agp-upgrade-assistant for more information.

* 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 4s

This is what I have done so far:

This is my gradlewrapper.properties file

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip

This is my Android level build.gradle file:

buildscript {
    ext.kotlin_version = '1.7.10'
    repositories {
        google()
        mavenCentral()
    }

    dependencies {
        classpath("com.android.tools.build:gradle:8.0.0")
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "com.google.gms:google-services:4.3.15"
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
    }
}

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

tasks.register("clean", Delete) {
    delete rootProject.buildDir
}

Here is my App level build.gradle file

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 plugin: 'com.google.gms.google-services'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

//I added this here for signingConfig
   def keystoreProperties = new Properties()
   def keystorePropertiesFile = rootProject.file('key.properties')
   if (keystorePropertiesFile.exists()) {
       keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
   }

android {
    compileSdkVersion 33
    ndkVersion flutter.ndkVersion

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = '1.8'
    }

    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.juliapak.coffeesociety"
        // You can update the following values to match your application needs.
        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-gradle-build-configuration.
        minSdkVersion 28
        targetSdkVersion 33
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

   //added for signing app
      signingConfigs {
       release {
           keyAlias keystoreProperties['keyAlias']
           keyPassword keystoreProperties['keyPassword']
           storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
           storePassword keystoreProperties['storePassword']
       }
   }
   buildTypes {
       release {
           signingConfig signingConfigs.release
       }
   }
  namespace 'com.juliapak.coffeesociety'
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation platform('com.google.firebase:firebase-bom:32.0.0')
    implementation 'com.google.firebase:firebase-analytics'
    }

I have tried switching distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip to 7.6.1 but it did not work either. As you can see I've also assigned a namespace. What do you recommend I do?

from experimentation, the problem is that 'namespace' needs to be specified in all modules, which includes ones from flutter packages..

coincidentally, i also had the same problem with package_info_plus.

with this SO thread, i managed to fix this specific error by adding this in the global build.grade:

subprojects{
    afterEvaluate {
        android {
            namespace 'add your namespace here'
        }
    }
}

The problem can be the version of Gradle, not all package support version 8.x.x yet.

I suggest you stay on version 7.