`querybean-generator:15.8.2` error: Failed to write `EntityClassRegister`

[raphaelNguyen]

Hi @rbygrave, I would like to report an issue when using querybean-generator:15.8.2 in tandem with another annotation processor.

Summary

When used in tandem with specific other annotation processor (in this case manifold-exceptions), the querybean-generator:15.8.2 logs an error while trying to write embedded.example.EbeanEntityRegister due to an NPE from deep inside the JavacFiler logging code.

Note that I actually have other annotation processors (e.g. lombok, errorprone, etc...) but as I was building the simple reproducible project, I found that using querybean-generator:15.8.2 alongside these other processors does not cause this issue. I've only observe the issue with manifold-exceptions.

Details

Environment

java: 17.0.13
ebean: 15.8.2
maven: 3.9.9
manifold-exceptions: 2024.1.5

Reproduction steps:

Reproducible project https://github.com/integrated-application-development/querybean-generator-processor-issue. The README.md in this project also contains explanations of this issue. This project is a sample project containing a few entity beans and using querybean-generator and manifold-exceptions annotation processors.

• Run mvn compile on the linked sample project.
• Observe the following error message when the compile goal runs.

[INFO] --- compiler:3.13.0:compile (default-compile) @ query-bean-embedded-example ---
[INFO] Recompiling the module because of changed source code.
[INFO] Compiling 3 source files with javac [forked debug deprecation target 17] to target\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] error: Failed to write EntityClassRegister error:java.lang.NullPointerException: Cannot invoke "java.util.Queue.add(Object)" because "this.deferred" is null stack:[jdk.compiler/com.sun.tools.javac.util.Log$DeferredDiagnosticHandler.report(Log.java:150), jdk.compiler/com.sun.tools.javac.util.Log.report(Log.java:660), jdk.compiler/com.sun.tools.javac.util.AbstractLog.warning(AbstractLog.java:163), jdk.compiler/com.sun.tools.javac.processing.JavacFiler.createSourceOrClassFile(JavacFiler.java:513), jdk.compiler/com.sun.tools.javac.processing.JavacFiler.createSourceFile(JavacFiler.java:435), io.ebean.querybean.generator.ProcessingContext.createWriter(ProcessingContext.java:399), io.ebean.querybean.generator.SimpleModuleInfoWriter.<init>(SimpleModuleInfoWriter.java:31), io.ebean.querybean.generator.Processor.writeModuleInfoBean(Processor.java:90), io.ebean.querybean.generator.Processor.process(Processor.java:53), jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:1023), jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment$DiscoveredProcessors$ProcessorStateIterator.runContributingProcs(JavacProcessingEnvironment.java:859), jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1265), jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1404), jdk.compiler/com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1234), jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:916), jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:317), jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:176), jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:64), jdk.compiler/com.sun.tools.javac.Main.main(Main.java:50)]
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------

Without manifold-exceptions

At querybean-generator version 15.8.2 without manifold-exception added to the path processors, the querybeans generation logs the warning below but completes successfully. The compilation also completes successfully unless -Werror compilation flag is turned on.

[INFO] --- compiler:3.13.0:compile (default-compile) @ query-bean-embedded-example ---
[INFO] Recompiling the module because of changed source code.
[INFO] Compiling 3 source files with javac [forked debug deprecation target 17] to target\classes
[WARNING] File for type 'embedded.example.EbeanEntityRegister' created in the last round will not be subject to annotation processing.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

Expected behaviour

compile does not throw any WARNING or ERROR related to querybean-generator.

Investigations

The stack trace suggests that this error happens when the underlying JavacFiler is trying to log the exact same [WARNING] observed above when running querybean-generator:15.8.2 without manifold-exceptions during JavacFiler.createSourceOrClassFile. When attempting this, the logging framework found that its DeferredDiagnosticHandler's deferred queue is null and threw an NPE which was captured and formatted into the [ERROR] seen above. A quick look at the code suggests that deferred queue is only set to null when DeferredDiagnosticHandler.reportDeferredDiagnostics is called to prevent accidental ongoing use.

This is likely linked to the changes made in #3542.

Part of the changes in this PR removes initModuleInfoBean() which creates SimpleModuleInfoWriter once if it's null and storing it in a instance field. Instead, it switches to creating a new SimpleModuleInfoWriter every time Processor.process is called. I had a sneaky feeling this might be what's causing the WARNING to be logged in the first place and did a quick test reverting this change (raphaelNguyen/ebean@fa8f98d). Using this locally installed version does not trigger the WARNING or ERROR mentioned above.

Thank you for your time.

[rbygrave]

Excellent investigation work, thanks!! I've created PR #3583 which mostly reverts that first commit and also catches the FilerException in order to support Quarkus dev mode / hot reload.

[raphaelNguyen]

Thanks for the prompt response @rbygrave. Cheers!