Fabric Beta and APK splits

I'm splitting my app based on ABI, not on density, like so:

    splits {
       abi {
           enable true
           reset()
           include 'x86', 'armeabi', 'armeabi-v7a', 'mips', 'arm64-v8a'
           universalApk true
       }
    }

I have multiple flavors, and 2 build types (debug and release). I want to put the universal apk file, that has native libs for all platforms, up on fabric beta. From what I understand, this is supported through the ext.betaDistributionApkFilePath attribute.

I can define this either at the buildType level, or at the flavor level. The problem is I need both build type and flavor to pick up my variant - something like this:

android.applicationVariants.all { variant ->
   variant.ext.betaDistributionApkFilePath = "${buildDir}/outputs/apk/app-${variant.productFlavors[0].name}-universal-${variant.buildType.name}.apk"
}

or

gradle.taskGraph.beforeTask { Task task ->
if(task.name ==~ /crashlyticsUploadDistribution.*/) {
   System.out.println("task name: ${task.name}");
   android.applicationVariants.all { variant ->
       System.out.println("match: crashlyticsUploadDistribution${variant.name}");
       if(task.name ==~ /(?i)crashlyticsUploadDistribution${variant.name}/){
           ext.betaDistributionApkFilePath = "${buildDir}/outputs/apk/app-${variant.productFlavors[0].name}-universal-${variant.buildType.name}.apk"
           System.out.println(ext.betaDistributionApkFilePath);
       }
   }
}

Unfortunately this doesn't seem to work - is there any way to do this currently?

For every existing variant you can add an action that will execute before Crashlytics tasks and set ext.betaDistributionApkFilePath according to the variant name. That's how it looks like:

android.applicationVariants.all { variant ->
  variant.outputs.each { output ->
    // Filter is null for universal APKs.
    def filter = output.getFilter(com.android.build.OutputFile.ABI)

    if (filter == null) {
      tasks.findAll {
        it.name.startsWith(
            "crashlyticsUploadDistribution${variant.name.capitalize()}")
      }.each {
        it.doFirst {
          ext.betaDistributionApkFilePath = output.outputFile.absolutePath
        }
      }

      tasks.findAll {
        it.name.startsWith(
            "crashlyticsUploadSymbols${variant.name.capitalize()}")
      }.each {
        it.doFirst {
          ext.betaDistributionApkFilePath = output.outputFile.absolutePath
        }
      }
    }
  }
}