Proguard error: "Exception while processing task java.io.IOException: Please correct the above warnings first"

Question

Since upgrading to android gradle plugin 3.0.1 I am getting following error:

Warning: Exception while processing task java.io.IOException: Please correct the above warnings first.

:app:transformClassesAndResourcesWithProguardForProductionRelease FAILED

Problem is: I don't see any warning in my log.

I also ran the build with -i flag and I am getting following (big) log: https://gist.github.com/stoefln/b5e5e899c73b52d8065a5daeead716b3

Any ideas are very welcome!

Answer 1

To view the warnings add the option -verbose to your proguard file and grep the warnings from the gradle output:

./gradlew -i clean assemble<buildtype> | grep -i "warning"

where build type can be Release or any other build type you defined which contains the proguard configuration.