Anyone use proguard or r8? According to https://firebase.google.com/docs/crashlytics/get-deobfuscated-reports?platform=android I have to add this for crashlytics to work. But if I "keep file names" doesn't that mean that obfuscastion isn't performed?

-keepattributes SourceFile,LineNumberTable        # Keep file names and line numbers.
-keep public class * extends java.lang.Exception  # Optional: Keep custom exceptions.

File name is just an attribute in the classfile, it doesn't have to correspond to the name of the class inside at all. The Kotlin compiler even sets the file name to be

Foo.kt

for all classes inside Foo.kt, even if those classes aren't named

Foo

.

It will make your stack traces more readable but will also leak some information about the source in the build (assuming there's some relation between your file names and the classes within).

The SourceFile is needed for the LineNumberTable. You can add renameresourcefileattribute to overwrite all names in the class file: https://stackoverflow.com/questions/6727872/when-obfuscating-with-proguard-does-keepattributes-sourcefile-linenumbertable

Yep, using renameresourcefileattribute is the best way and Firebase doesn't say you can't do this (but they also don't explicitly recommend it)

Intersting. I opened https://issuetracker.google.com/issues/243294051 just for the hell of it a few hours ago. but thanks everyone this was helpful