"cannot find reference class" with Proguard and Kotlin

Question

I had a strange problem with proguard and kotlin. I am gradually turning a stripped-down project into kotlin - which has gone very well so far, but I am getting proguard errors when converting certain classes. I have not yet been able to isolate what is a special property of these classes so that it breaks - they do not seem to differ from others. As an example, InputStreamWithSource is simple:

package org.ligi.passandroid.model import java.io.InputStream class InputStreamWithSource(val source: String, val inputStream: InputStream) 

and it works completely in the IDE - I can deploy it to the device - all UI tests work fine. Just when trying to build a project, I get proguard errors that I don’t understand:

 Warning: org.ligi.passandroid.ui.FileUnzipControllerSpec: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.FileUnzipControllerSpec: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.InputStreamProvider: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.InputStreamProvider: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.InputStreamProvider: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.InputStreamProvider: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.InputStreamProvider: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.InputStreamProvider: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassImportActivity$ImportAndShowAsyncTask: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassImportActivity$ImportAndShowAsyncTask: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassImportActivity$ImportAndShowAsyncTask: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassImportActivity$ImportAndShowAsyncTask: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassImportActivity$ImportAndShowAsyncTask: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassViewActivityBase$UpdateAsync: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassViewActivityBase$UpdateAsync: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.PassViewActivityBase$UpdateAsync: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.SearchPassesIntentService: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassController: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassController: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassController$InputStreamUnzipControllerSpec: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassController$InputStreamUnzipControllerSpec: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassController$InputStreamUnzipControllerSpec: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassController$InputStreamUnzipControllerSpec: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassDialog: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassDialog: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassDialog$1AlertDialogUpdater: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource Warning: org.ligi.passandroid.ui.UnzipPassDialog$1AlertDialogUpdater: can't find referenced class org.ligi.passandroid.model.InputStreamWithSource 

when I add dontwarn for these classes to the proguard configuration, than this happens at runtime, so these classes are really removed, but they should not be deleted as they are used.

I can work around this problem by adding a keep class / enum for these classes in proguard-config - but the question is why this is necessary for these classes - IMHO

Does anyone have any idea what might cause this or what is the best way to investigate this problem? The full source is here: https://github.com/ligi/PassAndroid

Answer 1

I would make sure that I have my own package defined in proguard - something like this:

 -dontwarn org.ligi.passandroid.** -keep class org.ligi.passandroid.** { *; }