IllegalArgumentException from ASM

Experiencing this issue when trying to Jib up the Groovy project at https://github.com/coollog/skaffold-code.one/tree/master/frontend-service

* What went wrong:
Execution failed for task ':jib'.
> java.lang.IllegalArgumentException (no error message)

* Try:
Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Exception is:
...
Caused by: java.lang.IllegalArgumentException
        at org.objectweb.asm.ClassVisitor.<init>(ClassVisitor.java:79)
        at org.objectweb.asm.ClassVisitor.<init>(ClassVisitor.java:64)
        at com.google.cloud.tools.jib.frontend.MainClassFinder$MainClassVisitor.<init>(MainClassFinder.java:123)
        at com.google.cloud.tools.jib.frontend.MainClassFinder$MainClassVisitor.<init>(MainClassFinder.java:111)
        at com.google.cloud.tools.jib.frontend.MainClassFinder.findMainClass(MainClassFinder.java:190)
        at com.google.cloud.tools.jib.frontend.MainClassFinder.find(MainClassFinder.java:161)
        at com.google.cloud.tools.jib.plugins.common.MainClassResolver.findMainClassInClassFiles(MainClassResolver.java:129)
        at com.google.cloud.tools.jib.plugins.common.MainClassResolver.resolveMainClass(MainClassResolver.java:61)
        at com.google.cloud.tools.jib.plugins.common.PluginConfigurationProcessor.computeEntrypoint(PluginConfigurationProcessor.java:278)
        at com.google.cloud.tools.jib.plugins.common.PluginConfigurationProcessor.processCommonConfiguration(PluginConfigurationProcessor.java:208)
        at com.google.cloud.tools.jib.plugins.common.PluginConfigurationProcessor.processCommonConfigurationForRegistryImage(PluginConfigurationProcessor.java:155)
        at com.google.cloud.tools.jib.gradle.BuildImageTask.buildImage(BuildImageTask.java:104)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
        at 
...

[javiersigler]

I could solve this problem by adding the main class to the Manifest

Example:

jar {
    manifest {
        attributes 'Main-Class': 'com.package.HelloWorld'
    }
}

[chanseokoh]

@MartijnDwars thanks for the feedback. Normally Gradle should pick up the most latest versions for dependencies when there are conflicts. However, we learned that it is a general and recurring issue in Gradle where an old version of a dependency is loaded in a multi-module Gradle project which leads to a frequent 'Method Not Found" or “Class Not Found” exception. The good news is that, with proper project configuration, this can be fixed, so in some sense, this is a Gradle configuration issue in your project. Check out this FAQ to learn more.

Or maybe the plugin could check the version of ASM that it runs with, and print an informative error message before the IllegalArgumentException that ASM produces.

Since this is a general Gradle configuration issue that can happen with any transitive dependencies of Jib (ASM happens to be the one here) and whose error can manifest in any unpredictable behavior (e.g., Method Not Found, or some behavior that works slightly differently, etc.), generally it doesn’t make much sense to increase Jib’s code complexity by adding a special handling for this particular IllegalArgummentException only for ASM. This is more or less out of the scope of Jib. However, if this particular error is frequent and consistent enough and many users keep running into it, it may not be unreasonable to try to catch this situation and return a helpful message. But for now, I think adding an FAQ entry is good enough. I’ll reopen this issue for tracking. Doc contributions are welcome.