IssueTracker

Here is a workaround:

abstract class VersionFileWriterTask extends DefaultTask {
    @OutputFile
    abstract RegularFileProperty getOutputFile();

    @TaskAction
    void run() {
        getOutputFile().get().asFile.write("foo bar this is created")
    }
}

import com.android.build.api.artifact.SingleArtifact

abstract class UpdateArtifactTask extends DefaultTask {
    @InputFiles
    abstract RegularFileProperty getInitialArtifact()

    @InputFile
    abstract RegularFileProperty getVersionFile()

    @OutputFile
    abstract RegularFileProperty getUpdatedArtifact()

    @TaskAction
    void taskAction() {
        // modify AAR by copying all entires, and adding resource to classes.jar entry
        getUpdatedArtifact().get().asFile.write("foo bar")
    }
}

def writeVersionFile = tasks.register("writeVersionFile", VersionFileWriterTask.class) {
    it.getOutputFile().fileValue(new File("build/version.txt"))
}

androidComponents {
    onVariants(selector().all(),  { variant ->
        def aarUpdates = tasks.register("updateAar${variant.name}", UpdateArtifactTask.class) {
            it.getVersionFile().set(writeVersionFile.flatMap { t -> t.getOutputFile()})
        }


        variant.artifacts.use(aarUpdates)
                .wiredWithFiles(
                        { UpdateArtifactTask t -> t.getInitialArtifact()},
                        { UpdateArtifactTask t -> t.getUpdatedArtifact()})
                .toTransform(SingleArtifact.AAR.INSTANCE)
    })
}

The issue is in

override fun asFileTree(
            fileTreeCreator: () -> ConfigurableFileTree,
    ): Provider<List<ConfigurableFileTree>> =
        directoryProvider.map {
            listOf(fileTreeCreator().setDir(directoryProvider).builtBy(directoryProvider))
        }

Inner .map captures fileTreeCreator() with this pointing to AGP global objects.

Rewriting it to:

override fun asFileTree(
        fileTreeCreator: () -> ConfigurableFileTree,
    ): Provider<List<ConfigurableFileTree>> {
        val fileTre = fileTreeCreator().setDir(directoryProvider).builtBy(directoryProvider)
        return directoryProvider.map {
            listOf(fileTre)
        }
    }

which is also lazy, fixes the issue.

This should be fixed in AGP 8.0.0-beta01 and 8.1.0-alpha01.

Fixed in change-id: I92dbae7099b0bacea675527d247dd8da77ec326c.

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 Giraffe Canary 1 (2022.3.1.1)
• Android Gradle Plugin 8.1.0

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!