What ProGuard configuration do I need for Firebase on Android?

Question

When using the Firebase SDK for Android apps, I keep getting warnings and errors like these (in Eclipse):

Warning ... can't find referenced class ... Warning: there were ... unresolved references to classes or interfaces ... You may need to specify additional library jars (using '-libraryjars') ... 

Unfortunately, Firebase doesn't have any official documentation about its use with ProGuard.

What directives do I need for my apps to successfully compile releases with Firebase when obfuscated with ProGuard?

Answer 1

Based on my personal tests, it turned out something along these lines is necessary for Firebase-enhanced Android apps to compile with ProGuard.

In any case, you have to add -keepnames class com.my.package.beans.** { *; } if you are using custom objects in your Firebase, i.e. beans or POJOs.

Firebase SDK 1.0.18:

-keepnames class com.firebase.** { *; } -keepnames class com.shaded.fasterxml.jackson.** { *; } -keepnames class org.shaded.apache.** { *; } -keepnames class javax.servlet.** { *; } -dontwarn org.w3c.dom.** -dontwarn org.joda.time.** -dontwarn org.shaded.apache.commons.logging.impl.** 

Firebase SDK 1.1.1:

-keep class com.firebase.** { *; } -keep class org.shaded.apache.** { *; } -keepnames class com.shaded.fasterxml.jackson.** { *; } -keepnames class javax.servlet.** { *; } -keepnames class org.ietf.jgss.** { *; } -dontwarn org.w3c.dom.** -dontwarn org.joda.time.** -dontwarn org.shaded.apache.** -dontwarn org.ietf.jgss.** 

Firebase SDK 2.0.0:

-keep class com.firebase.** { *; } -keep class org.apache.** { *; } -keepnames class com.fasterxml.jackson.** { *; } -keepnames class javax.servlet.** { *; } -keepnames class org.ietf.jgss.** { *; } -dontwarn org.w3c.dom.** -dontwarn org.joda.time.** -dontwarn org.shaded.apache.** -dontwarn org.ietf.jgss.**  # Only necessary if you downloaded the SDK jar directly instead of from maven. -keep class com.shaded.fasterxml.jackson.** { *; } 

Last resort:

-keep class !com.my.package.** { *; } 

Notes:

Any official guideline would be welcome. The -dontwarn directives are obviously dangerous, code may break at points that I have not tested. Furthermore, the above rules are quite permissive and other rules may better optimize your APKs.

Answer 2

I found this in Firebase documentations:

When using Firebase Realtime Database in your app along with ProGuard you need to consider how your model objects will be serialized and deserialized after obfuscation. If you use DataSnapshot.getValue(Class) or DatabaseReference.setValue(Object) to read and write data you will need to add rules to the proguard-rules.pro file:

# Add this global rule     -keepattributes Signature  # This rule will properly ProGuard all the model classes in  # the package com.yourcompany.models. Modify to fit the structure # of your app. -keepclassmembers class com.yourcompany.models.** { *; }