ProGuard/R8 rules

Proguard (and its successor, R8) is a code-shrinking and obfuscation tool used by Android when building release apps. Without the necessary rules in place, Proguard might strip or rename classes that an SDK needs at runtime that causes app crashes.

The Didomi Android SDK includes ProGuard rules in its Android Archive (AAR) that is automatically applied to any Android application that integrates the SDK. Your organization does not need to copy or references these rules manually as they will take effect at build time. In this article, we provide an overview of the different ProGuard/R8 rules that are packaged with the Didomi Android SDK:

• Core Didomi SDK classes rules

• Defensive/housekeeping rules

• Gson rules

• Firebase rules

If your organization has a custom ProGuard configuration that conflicts (e.g. aggresive -keep or -obfuscate overrides) it my need to verify that these rules are not being overridden.

Core Didomi SDK classes rules

The following rules tell ProGuard to leave Didomi SDK classes untouched (they should not be removed nor renamed):

-keep class io.didomi.iabtcf.** { *; }
-keep class io.didomi.sdk.** { *; }

Defensive/housekeeping rules

Rule	Description
-keep,allowshrinking,allowobfuscation enum io.didomi.iabtcf.decoder.v2.RestrictionType	Preserves a specific enum used in TCF v2 decoding to work around a known bug in certain ProGuard versions
-dontwarn com.eclipsesource.v8.V8	Suppresses a build warning about V8 (a JavaScript engine). The SDK no longer depends on V8 at runtime, but a reference may linger in the dependency tree.
-dontwarn kotlinx.parcelize.Parcelize	Suppresses a warning about Kotlin's @Parcelize annotation plugin in certain build configurations.

Gson rules

The following rules are used to handle Gson:

Rule	Description
-keepattributes Signature	Preserves generic type information Gson needs to read JSON into typed objects
-keepattributes *Annotation*	Keeps @Expose and other Gson annotations
-dontwarn sun.misc.**	Suppresses a known harmless warning from Gson internals
-keep class * extends com.google.gson.TypeAdapter	Protects custom JSON adapters from being stripped
-keep class * implements com.google.gson.TypeAdapterFactory	Protects custom JSON adapter factories from being stripped
-keep class * implements com.google.gson.JsonSerializer/Deserializer	Protects custom serializer/deserializer implementations
-keepclassmembers … @SerializedName	Prevents R8 from nullifying fields mapped from JSON using the @SerializedName annotation
-keep class com.google.gson.reflect.TypeToken	Required for R8 v3.0+ to correctly handle generic type tokens

Firebase rules

The following rules apply to Android applications that use the Didomi Android SDK and Firebase Analytics with Google Consent Mode v2 enabled. Together, these rules protect Firebase Analytics classes that the Didomi Android SDK's Google Consent Mode v2 integration calls via reflection.

Reflection is a technique where code calls another class's methods by name at runtime rather than at compile time. This technique requires explicit ProGuard protection.

-dontwarn com.google.firebase.analytics.FirebaseAnalytics
-keep class com.google.firebase.analytics.FirebaseAnalytics$ConsentType { *; }
-keep class com.google.firebase.analytics.FirebaseAnalytics$ConsentStatus { *; }
-keepclassmembers class com.google.firebase.analytics.FirebaseAnalytics {
    public void setConsent(java.util.Map);
}