The documentation of obfuscation should mention Proguard `-keep` rules

[dkhalanskyjb]

Describe the bug

https://github.com/JetBrains/compose-multiplatform/tree/master/tutorials/Native_distributions_and_local_execution#minification--obfuscation provides inaccurate instructions. When followed, they will lead to a project that doesn't work. See https://github.com/JetBrains/compose-multiplatform/issues/3047 and https://github.com/Kotlin/kotlinx.coroutines/issues/4025.

Affected platforms

• Desktop

Versions

Current master as of writing.

To Reproduce

1. Follow the steps in https://github.com/JetBrains/compose-multiplatform/tree/master/tutorials/Native_distributions_and_local_execution#minification--obfuscation
2. Try running your project.
3. Observe the exception "Module with the Main dispatcher is missing."

Expected behavior The project works.

Screenshots Not applicable.

Additional context The rule that seems to do the trick is:

-keep class * implements kotlinx.coroutines.internal.MainDispatcherFactory

Anecdotally, this seems to be sufficient.

If some other issues arise with Proguard + Coroutines, here's the full list of rules that were needed for Proguard at some point https://github.com/Kotlin/kotlinx.coroutines/blob/13f27f729547e5c22d17d5b5de3582d450b037b4/kotlinx-coroutines-core/jvm/resources/META-INF/com.android.tools/proguard/coroutines.pro . A lot of this is probably only needed for older Proguard versions, though.

[okushnikov]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.