Android Proguard compile time constant

Question

Ok so i have this use case:

 override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        if (loginManager.isLoggedIn()) {
            if(BuildConfig.IS_FLAVOR_A){
                ActivityA.startActivity(this)
            } else if(BuildConfig.IS_FLAVOR_B){
                ActivityB.startActivity(this)
            }
        } else {
            ActivityC.startActivity(this)
        }
        this.finish()
    }

BuildConfig.IS_FLAVOR_A

is a flag present in the productFlavors that identify a flavour. ActivityB is only ever referenced here, and i would expect Proguard to remove ActivityB and all its resources but it isn't.

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

    }

What is missing? Can i really accomplish this? Flavours compile-time constants allow proguard to remove unused codes, in the case, ActivityB.startActivity(this)

EDIT: Proguard Rules

-dontobfuscate
#-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*,!code/allocation/variable

# AdvancesWebView
-keep class * extends android.webkit.WebChromeClient { *; }

# RxJava
-dontwarn sun.misc.**

-keepclassmembers class rx.internal.util.unsafe.*ArrayQueue*Field* {
   long producerIndex;
   long consumerIndex;
}

-keepclassmembers class rx.internal.util.unsafe.BaseLinkedQueueProducerNodeRef {
    rx.internal.util.atomic.LinkedQueueNode producerNode;
}

-keepclassmembers class rx.internal.util.unsafe.BaseLinkedQueueConsumerNodeRef {
    rx.internal.util.atomic.LinkedQueueNode consumerNode;
}

# Retrofit2
-dontwarn retrofit2.**
-keep class retrofit2.** { *; }
-keepattributes Signature
-keepattributes Exceptions

-keepclasseswithmembers class * {
    @retrofit2.http.* <methods>;
}

#OKHttp
-dontwarn okio.**

# RxBle
-dontwarn com.polidea.**

# Support v4
-dontwarn android.support.v4.**

#Anko
-dontwarn org.jetbrains.anko.internals.AnkoInternals

#Support v7
-keep public class android.support.v7.widget.** { *; }
-keep public class android.support.v7.internal.widget.** { *; }
-keep public class android.support.v7.internal.view.menu.** { *; }

-keep public class * extends android.support.v4.view.ActionProvider {
    public <init>(android.content.Context);
}

# CardView
-keep class android.support.v7.widget.RoundRectDrawable { *; }

#Support Design
-dontwarn android.support.design.**
-keep class android.support.design.** { *; }
-keep interface android.support.design.** { *; }
-keep public class android.support.design.R$* { *; }

#Glide
-keep public class * implements com.bumptech.glide.module.GlideModule
-keep public enum com.bumptech.glide.load.resource.bitmap.ImageHeaderParser$** {
    **[] $VALUES;
    public *;
}

#Moshi
-keepclassmembers class ** {
    @com.squareup.moshi.FromJson *;
    @com.squareup.moshi.ToJson *;
}

Answer 1

You need to enable optimization. To do that, use this configuration instead:

proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'),'.../proguard-rules.pro'