ProGuard with AppBundle and data-binding: IllegalStateException

Only need to add this to your proguard-rules.pro, where module1 and module2 are Dynamic Feature Modules with databinding enabled.

-keep class com.example.module1.DataBinderMapperImpl { *; } 
-keep class com.example.module2.DataBinderMapperImpl { *; } 

I don't really know why but for me, the following combination worked:

-dontwarn androidx.databinding.**
-keep class androidx.databinding.** { *; }
-keep class * extends androidx.databinding.DataBinderMapper

I tried using just -keep class * extends androidx.databinding.DataBinderMapper but it didn't work.

Also I tried using

-dontwarn androidx.databinding.**
-keep class androidx.databinding.** { *; }

but that didn't work either.

What worked was a combination of the three.