Build fails when using picocli-codegen

[xligrd]

I set up picocli-codegen as an annotation processor and from that point on build always fails with:

error: FATAL ERROR: java.lang.ClassCastException: class com.sun.tools.javac.code.Attribute$Class cannot be cast to class javax.lang.model.type.TypeMirror (com.sun.tools.javac.code.Attribute$Class is in module jdk.compiler of loader 'app'; javax.lang.model.type.TypeMirror is in module java.compiler of loader 'platform')
at picocli.codegen.annotation.processing.CompletionCandidatesMetaData.extract(CompletionCandidatesMetaData.java:44)
at picocli.codegen.annotation.processing.AbstractCommandSpecProcessor.buildOption(AbstractCommandSpecProcessor.java:499).

Where the related code looks like:

public static class LevelCompletion extends ArrayList<String> {
        public LevelCompletion() {
            super(Arrays.asList("OFF", "INFO", "WARN", ));
        }
    }

    @CommandLine.Option(names = "--level",
                        description = "Level.",
                        defaultValue = "OFF", 
                        showDefaultValue = CommandLine.Help.Visibility.ALWAYS,
                        completionCandidates = LevelCompletion.class)
    private Level level;

Am I doing something wrong or is it bug?

[remkop]

@xligrd Thank you for raising this.
I started investigating this.
Could you please provide some version information:

• picocli version
• java version
• whether this error occurs when you are compiling in an IDE (which one?) or building with Maven/Gradle/some other build tool

Thanks!

[xligrd]

Many thanks for quick reaction.
I tried multiple versions of picocli (4.1.4, 4.3.2 and 4.4.0), java version was 11.0.7 and It was built using Gradle.

[remkop]

I would like to try to reproduce the problem.
Can you point me to a public repository or show me how to create a small project that reproduces the error?

[xligrd]

Sure. I'm attaching a minimalistic application using which I was able to reproduce it.
picocli-test.zip

[remkop]

@xligrd Please disregard my previous comment: I was able to reproduce the issue.
This seems to be a bug in the picocli-codegen annotation processor.

I am looking at how to fix this.

[remkop]

@xligrd Thank you! 😅

[xligrd]

Np :)

[remkop]

I think I found the cause:

Index: picocli-codegen/src/main/java/picocli/codegen/annotation/processing/CompletionCandidatesMetaData.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- picocli-codegen/src/main/java/picocli/codegen/annotation/processing/CompletionCandidatesMetaData.java	(date 1595924589896)
+++ picocli-codegen/src/main/java/picocli/codegen/annotation/processing/CompletionCandidatesMetaData.java	(date 1595924589896)
@@ -41,7 +41,7 @@
                 for (ExecutableElement attribute : elementValues.keySet()) {
                     if ("completionCandidates".equals(attribute.getSimpleName().toString())) {
                         AnnotationValue typeMirror = elementValues.get(attribute);
-                        return new CompletionCandidatesMetaData((TypeMirror) typeMirror);
+                        return new CompletionCandidatesMetaData((TypeMirror) typeMirror.getValue());
                     }
                 }
             }

I will add some tests to verify this and try to roll out a bugfix release for this soon.
Thanks again for raising this!

[xligrd]

Thanks a lot.

[remkop]

I finally had time to create a test to confirm that this indeed fixes the issue.

Thanks again for raising this.
I will try to roll out a bugfix release soon (perhaps after fixing #1134).