[GROOVY-9506] Joint compilation is broken

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.5.10
• Fix Version/s: 4.0.0-alpha-1, 3.0.4, 2.5.12
• Assignee: Paul King
• Reporter: Daniil Ovchinnikov
• Created: 13/Apr/20 17:05
• Updated: 22/May/20 04:02
• Resolved: 16/May/20 10:36

Description

playground.groovy

@groovy.transform.AutoImplement
class C implements Runnable {}

class Main {
    static void main(String[] args) {
        def c = new C()
        c.run()
    }
}

I.java

public interface I {
  void foo();
}

$ groovyc I.java playground.groovy -j
$ java -cp .:$GROOVY_HOME/lib/groovy-2.5.10.jar Main
Exception in thread "main" java.lang.NullPointerException
	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:37)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:115)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:119)
	at Main.main(playground.groovy:9)

What happens:
1. org.codehaus.groovy.tools.javac.JavaStubGenerator#printClassContents applies its Verifier.
2. org.codehaus.groovy.classgen.Verifier#addGroovyObjectInterfaceAndMethods adds GroovyObject interface and GroovyObject's methods via org.codehaus.groovy.classgen.Verifier#addMethod.
3. Verifier#addMethod is overridden in #printClassContents' Verifier to skip adding methods to the class node.
4. at the moment when @AutoImplement kicks in there exists the GroovyObject interface and no methods in the class node, so the transformation adds default method implementations.

Related: https://youtrack.jetbrains.com/issue/IDEA-237148