[MCOMPILER-369] Adding module-info.java breaks JMH annotation processor

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.8.0
• Assignee: Unassigned
• Reporter: Gili
• Created: 26/Dec/18 07:14
• Updated: 23/May/24 15:02

Description

1. Open testcase
2. Run clean install. Notice that the benchmarks run.
3. Open pom.xml and comment-out the <annotationProcessorPaths> section.
4. Run clean install. Notice that the annotation processor does not run and the benchmarks break.
5. Delete/rename module-info.java.
6. Run clean install. Notice that the benchmarks work again.

The documentation for <annotationProcessorPaths> states that by default annotation processors are detected from the classpath. It seems that adding module-info.java breaks that somehow, which is weird/unexpected because JMH exists as a dependency outside the newly-declared module.

I did two things to prove that the annotation processor is not being invoked in step 4:

1. Notice that target/test-classes/META-INF is not created.
2. Place a breakpoint in org.openjdk.jmh.generators.BenchmarkProcessor and notice that it is never even constructed.

I tried digging into the maven-compiler-plugin and plexus-compiler source-code but couldn't figure out where the problem is. The only workaround I found is to specify annotationProcessorPaths manually but it took me half a day to track down this problem.

Any idea what is going on? Is this a bug in the plugin(s)?