Add R8 keep rule for Hilt_* base classes to fix ClassCastException in release builds#5195
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Senthil455 wants to merge 1 commit into
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Add R8 keep rule for Hilt_* base classes to fix ClassCastException in release builds#5195Senthil455 wants to merge 1 commit into
Senthil455 wants to merge 1 commit into
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… release builds In R8 full mode (android.enableR8.fullMode=true), R8's aggressive vertical class merging optimization merges @androidentrypoint classes with their generated Hilt_* base classes. This breaks the bytecode-transformed class hierarchy set up by the Hilt Gradle plugin, causing a ClassCastException at runtime when the Android system tries to create the service/activity. The existing keep rules only preserve @EntryPoint-annotated classes, but not the generated Hilt_* base classes themselves. Adding -keep class **.Hilt_* prevents R8 from merging these generated classes, preserving the class hierarchy required for Hilt's bytecode transformation to work correctly. Fixes google#4668
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Problem
When using @androidentrypoint on a class (e.g., a Service, Activity, or BroadcastReceiver) with R8 full mode enabled (�ndroid.enableR8.fullMode=true), the app crashes at runtime with:
java.lang.RuntimeException: Unable to create service *.presentation.service.PushMessagingService: java.lang.ClassCastExceptionThis works correctly in debug builds and when R8 full mode is disabled.
Root Cause
In R8 full mode, the aggressive vertical class merging optimization merges @androidentrypoint user classes with their generated Hilt_* base classes when the user class has no additional methods. For example, PushMessagingService (which is : FirebaseMessagingService()) would be merged with Hilt_PushMessagingService into a single class.
This merging breaks the bytecode-transformed class hierarchy that the Hilt Gradle plugin set up via AndroidEntryPointClassVisitor. The plugin rewrites @androidentrypoint classes to extend Hilt_* instead of their original superclass. When R8 undoes this by merging the classes, a ClassCastException occurs at runtime when the Android system tries to create the service.
Fix
Added -keep class .Hilt_ to the Hilt Android proguard rules. This prevents R8 from merging the generated Hilt_ base classes with user classes, preserving the class hierarchy required for Hilt's bytecode transformation to work correctly.
The existing keep rules only preserve @EntryPoint-annotated classes, but not the generated Hilt_* base classes themselves.
Changes
Fixes #4668