cykl / record-builder-139-reproducer

record-builder #139 reproducer

This repository contains a minimal reproducer for Randgalt/record-builder#139.

Use ./trigger.sh to reproduce the issue. The second mvn compile should fail with the following error

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.10.1:compile (default-compile) on project record-builder-139-reproducer: Fatal error compiling: java.lang.NullPointerException: Cannot invoke "javax.lang.model.element.ExecutableElement.getAnnotationMirrors()" because the return value of "javax.lang.model.element.RecordComponentElement.getAccessor()" is null -> [Help 1]

To understand what is going on you can use mvnDebug rather than mvn for the second build and set following breakpoints:

1. com.sun.tools.javac.code.Symbol.ClassSymbol.setRecordComponents

2. com.sun.tools.javac.code.Symbol.ClassSymbol.getRecordComponent(com.sun.tools.javac.tree.JCTree.JCVariableDecl, boolean, com.sun.tools.javac.util.List<com.sun.tools.javac.tree.JCTree.JCAnnotation>) with condition var.name.toString().contains("Concurrency")

3. io.soabase.recordbuilder.processor.InternalRecordBuilderProcessor.buildRecordComponents

First one allows to observe that javac parses the class file from the first build and add a record component for maxConcurrency with pos = -1 and no accessor.

The second one allow to observe that a second record component is added at a latter stage. Since pos != 1, TypeElement for ConfRecord ends up with two record components for maxConcurrency one of them having no accessor.