IssueTracker

I encountered the same error (using full mode R8).

Anyone has the correct rules as a workaround until the next version is released?

Following R8 rules when using DataStore with Preferences are working okay for me:

-keepclassmembers class androidx.datastore.preferences.PreferencesProto$PreferenceMap {
    private androidx.datastore.preferences.protobuf.MapFieldLite preferences_;
}

-keepclassmembers class androidx.datastore.preferences.PreferencesProto$Value {
     private java.lang.Object value_;
     private int valueCase_;
}

Project: platform/frameworks/support
Branch: androidx-master-dev

commit ba352589a039f23c1450755ca3a76a50b9722e69
Author: rohitsat13 <rohitsat@google.com>
Date:   Mon Sep 21 16:15:24 2020

    Fix the crash with DataStore R8. I think this is happening because protobuf-lite uses reflection and r8 thinks the fields are unused.
   
    Test: I added minifyEnabled to the sample app, and it crashes without this change, but it works fine with this change. I also did the same with the preferences datastore codelab
    Bug: 168580258
    Relnote: Fixing a bug that would cause the app to crash on start up
    Change-Id: I69237e3036c4863c3aa011cd88f363441ae5999f

M       datastore/datastore-preferences/build.gradle
A       datastore/datastore-preferences/proguard-rules.pro
M       datastore/datastore-sampleapp/src/main/java/com/example/datastoresampleapp/PreferencesDataStoreActivity.kt

https://android-review.googlesource.com/1433465

This will be fixed in the next release.

With https://android-review.googlesource.com/c/platform/frameworks/support/+/1433465/