IssueTracker

First, the configuration snippet is not quite right, you wrote :

androidComponents {  
  finalizeDsl {
    onVariants { variant ->
      val generateCustomManifestTask = target.tasks.register<GenerateCustomManifestTask>("generate${variant.name.capitalized()}CustomManifest")
      variant.androidTest?.sources?.manifests?.addGeneratedManifestFile(generateCustomManifestTask, GenerateCustomManifestTask::manifestProperty)
    }
  }
}

but it really should be

androidComponents {  
    onVariants { variant ->
      val generateCustomManifestTask = target.tasks.register<GenerateCustomManifestTask>("generate${variant.name.capitalized()}CustomManifest")
      variant.androidTest?.sources?.manifests?.addGeneratedManifestFile(generateCustomManifestTask, GenerateCustomManifestTask::manifestProperty)
    }
}

The finalizeDsl block is to finalize the DSL objects before the variants are created. It's just a Gradle DSL quirk that it does not generate an exception as Gradle will look for onVariants method in the parent hierarchy of the finalizeDsl block. Of course if finds it in androidComponents block !

Issues reproducing

In any case, I have tried to reproduce the issue with both the correct configuration and incorrect configuration block and it works fine on my end using 8.4.0 all the way to 8.6.0-dev.

I have attached the full project I used so you can find what's different. If you can modify it to reproduce your issue, that would be great.

It's a bit different than yours because mainly it was easier to use groovy with our current test infrastructure but you will see in the build.gradle file that I more or less copied your code :

androidComponents {
    onVariants(selector().all(), { variant ->
        def generateCustomManifestTask = tasks.register("generate${variant.name.capitalize()}CustomManifest", GenerateCustomManifestTask)

        if (variant.androidTest != null) {
            variant.androidTest.sources.manifests.addGeneratedManifestFile(generateCustomManifestTask, { it.getManifestProperty() })
        }
    })
}

abstract class GenerateCustomManifestTask extends DefaultTask {
    @OutputFile
    abstract RegularFileProperty getManifestProperty()

    @TaskAction
    void generateManifest() {
        String manifest = """
            <manifest xmlns:android="http://schemas.android.com/apk/res/android"
                android:versionCode="00000000"
                android:versionName="0.0.0">

                <permission
                    android:name="foo.generated.SEND_TEXT"
                    android:description="@string/app_name"
                    android:label="@string/app_name"
                    android:permissionGroup="foo.permission-group.COST_MONEY" />
            </manifest>
        """.stripIndent()

        File manifestFile = manifestProperty.get().asFile
        manifestFile.write(manifest)
    }
}

Steps to use the sample

1. unzip the file
2. go to testGeneratedManifestIsUsed/androidManifestInTest folder
3. <path_to_gradle>/gradlew assembleDebugAndroidTest

Result

and the resulting merged AndroidManifest.xml does contain the permission I added above, and the version changes :

 ~/bugs/341124476/testGeneratedManifestIsUsed/androidManifestInTest  cat ./build/intermediates/packaged_manifests/debugAndroidTest/processDebugAndroidTestManifest/AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.tests.basic.test"
    android:versionCode="00000000"
    android:versionName="0.0.0" >

    <uses-sdk
        android:minSdkVersion="16"
        android:targetSdkVersion="16" />

    <permission
        android:name="foo.generated.SEND_TEXT"
        android:description="@string/app_name"
        android:label="@string/app_name"
        android:permissionGroup="foo.permission-group.COST_MONEY" />

    <instrumentation
        android:name="android.support.test.runner.AndroidJUnitRunner"
        android:functionalTest="false"
        android:handleProfiling="false"
        android:label="Tests for com.android.tests.basic"
        android:targetPackage="com.android.tests.basic" >
        <meta-data
            android:name="listener"
            android:value="android.support.test.internal.runner.listener.ManifestListener" />
    </instrumentation>

    <permission-group
        android:name="foo.permission-group.COST_MONEY"
        android:description="@string/app_name"
        android:label="@string/app_name" />

    <permission
        android:name="foo.permission.RECEIVED_SMS"
        android:description="@string/app_name"
        android:label="@string/app_name"
        android:permissionGroup="foo.permission-group.COST_MONEY" />

    <application
        android:debuggable="true"
        android:extractNativeLibs="true" >
        <uses-library android:name="android.test.runner" />
    </application>

</manifest>%

functional project attached.

Thank you for the sample project. I did run it & can see that the attributes from the generated manifest get merged. However, this is because you have an existing AndroidManifest.xml in the androidTest sourceset. If you delete the existing AndroidManifest.xml, the generated attributes disappear from the merged manifest.

It seems like having an existing AndroidManifest.xml in the androidTest sourceset is required for this work, even if that manifest declares nothing. For example, if I replace the AndroidManifest.xml at testGeneratedManifestIsUsed/androidManifestInTest/src/androidTest/, it still works with just:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"/>

However, delete the file & it stops working as the generated AndroidManifest.xml is no longer merged

Ah ok, that make sense, ok so for now you have a workaround.

I will look into fixing this asap.

thanks for the report !

reducing to P2 as there is a workaround.

Fixed in Koala feature drop

Thank you for your patience while our engineering team worked to resolve this issue. A fix for this issue is now available in:

• Android Studio Koala Feature Drop | 2024.1.2 Canary 3
• Android Gradle Plugin 8.6.0-alpha03

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

Thank you for taking the time to submit feedback — we really appreciate it!