Hello everyone. When I obfuscate an app with R8 th...

# random

[Francis Mariano]

Hello everyone. When I obfuscate an app with R8 the ClassCastException is raised. Without R8 the cast work normally. Is there any channel here for discuss about that??

java.lang.ClassCastException: java.lang.Float cannot be cast to u1.Z
    at J1.d.q(Unknown Source:142)
    at J1.d.j(Unknown Source:12)
    at C4.D.b(Unknown Source:260)
    at X5.w.j(Unknown Source:131)
    at X5.j.q(Unknown Source:11)
    at y5.a.s(Unknown Source:8)
    at T5.L.run(Unknown Source:112)
    at b6.a.run(Unknown Source:95)
    Suppressed: Z5.f: [u0{Cancelling}@513cb02, Dispatchers.Default]

[Pablichjenkov]

We need an R8 channel!

[Chrimaeon]

not kotlin but kotlin colored 😉

[Chrimaeon]

How does the code look like?

[Pablichjenkov]

Isn't r8 the default kotlin obfuscator?

[Chrimaeon]

No, it’s part of the Android Gradle plugin 🙂

[Chrimaeon]

https://r8.googlesource.com/r8/+/refs/heads/main/README.md

[eygraber]

It actually could (and sometimes should) be used separately from Android, but I'm not sure if this community is the best place to get help with.

Since we're in #C09222272 (so not technically off-topic) I can point you in the right direction.

When the APK or AAB is built and R8 obfuscation is enabled a mapping.txt file will be generated that holds the mapping of the obfuscated symbols to the original ones.

In your Android SDK directory under cmdline-tools/latest/bin there is a tool called retrace that you supply the path to your mapping.txt and then give it the stacktrace that you want to de-obfuscate.

[eygraber]

https://developer.android.com/tools/retrace

[Francis Mariano]

Thank you all you, I use class name to do some logics, so the name was obfuscated and my logic was bad. I added -keepclasseswithmembernames class * and all works fine now.

[louiscad]

R8 has Kotlin specific rules @Chrimaeon, and it works also on non Android stuff. We have github.com/GradleUp/gr8 for example

[Chrimaeon]

yeah, sure, I know. Still it is a tool provided by Google and should not have a channel in this workspace.

[louiscad]

That's your opinion 😉

[louiscad]

There are a bunch of channels regarding Kotlin related tools made by various people or companies on this Slack