query-bean-generator-issue

This project illustrate an issue with the ebean query bean generator. Issue as of ebean version 15.8.2 can be reproduced by running mvn compile on this example project. Issue has been raised at ebean-orm/ebean#3582.

When generating querybeans along side specific other annotation processors (in this case manifold-exceptions), the querybean-generator logs an error while trying to write embedded.example.EbeanEntityRegister and fails the build (error details below).

Pre-15.8.2 Behaviour

With or without manifold-exception, the generator just generate without any [WARNING] or [ERROR] logs.

15.8.2 Behaviour

This behaviour can be reproduced with just querybean-generator upgraded to 15.8.2 while keeping other ebean dependencies at an older version (e.g. 15.8.1). But for simplicity, this example set all ebean dependencies version at 15.8.2.

Without manifold-exception

This case can be reproduced in this sample project by commenting out manifold-exception at line 56 and 59-63 in pom.xml.

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 sucessfully 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] ------------------------------------------------------------------------

With manifold-exception

With manifol-exception added to the path processors, the querybeans generation logs the compilation error below and failed the build.

[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] ------------------------------------------------------------------------

The stack trace suggests that this issue happens when the underlying JavacFiler is trying to log the exact same [WARNING] observed above when running querybean-generator version 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.