IssueTracker

With r8-full-mode enabled in AGP 8.3.2 by default, we encountered a number of ClassCastExceptions from many classes within the androidx packages. These exceptions can be avoided by putting proguard keep rules individually, but there seems to be a systematic error inside r8 full-mode.

It seems related to a universal inner class ExternalSyntheticOutline0, the following are some examples

java.lang.ClassCastException at androidx.core.app.NavUtils$$ExternalSyntheticOutline0.m(SourceFile:88)

java.lang.ClassCastException at androidx.tracing.Trace$$ExternalSyntheticOutline0.m(SourceFile:88)

java.lang.ClassCastException at androidx.fragment.app.Fragment$5$$ExternalSyntheticOutline0.m(SourceFile:76)

The keep rules that I have tried are the following

# ClassCastException encountered by enabling r8 full-mode as of AGP 8.3.2
-keep class androidx.core.app.NavUtils { *; }
-keep class androidx.core.math.MathUtils { *; }
-keep class androidx.tracing.Trace { *; }
-keep class androidx.core.view.ViewKt { *; }
-keep class androidx.room.util.CursorUtil { *; }
-keep class androidx.room.util.DBUtil { *; }
-keep class androidx.core.os.BundleKt { *; }
-keep class androidx.core.net.UriKt { *; }
-keep class androidx.compose.ui.SessionMutex { *; }
-keep class androidx.fragment.app.Fragment.** { *; }