Adding a custom record constructor prevents successful compilation

[andreaskornstaedt]

**GWT version: 2.12.1
**Browser (with version): any
**Operating System: any

---

Description

A custom record constructor prevents successful compilation even if never invoked

         Compiling 1 permutation
            Compiling permutation 0...
            [ERROR] An internal compiler exception occurred
com.google.gwt.dev.jjs.InternalCompilerException: Unexpected error during visit.
	at com.google.gwt.dev.jjs.ast.JVisitor.translateException(JVisitor.java:111)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:130)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:122)
	at com.google.gwt.dev.jjs.ast.JTransformer.transform(JTransformer.java:1100)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transform(GenerateJavaScriptAST.java:2659)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformDeclarationStatement(GenerateJavaScriptAST.java:686)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformDeclarationStatement(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:725)
	at com.google.gwt.dev.jjs.ast.JDeclarationStatement.traverse(JDeclarationStatement.java:46)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:122)
	at com.google.gwt.dev.jjs.ast.JTransformer.transform(JTransformer.java:1100)
	at com.google.gwt.dev.jjs.ast.JTransformer.transformIntoExcludingNulls(JTransformer.java:1120)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformBlock(GenerateJavaScriptAST.java:583)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformBlock(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:647)
	at com.google.gwt.dev.jjs.ast.JBlock.traverse(JBlock.java:93)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:122)
	at com.google.gwt.dev.jjs.ast.JTransformer.transform(JTransformer.java:1100)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transform(GenerateJavaScriptAST.java:2672)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformMethodBody(GenerateJavaScriptAST.java:833)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformMethodBody(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:854)
	at com.google.gwt.dev.jjs.ast.JMethodBody.traverse(JMethodBody.java:81)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:122)
	at com.google.gwt.dev.jjs.ast.JTransformer.transform(JTransformer.java:1100)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformMethod(GenerateJavaScriptAST.java:804)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.generatePrototypeDefinitions(GenerateJavaScriptAST.java:2474)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.generateTypeSetup(GenerateJavaScriptAST.java:1951)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformDeclaredType(GenerateJavaScriptAST.java:649)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformDeclaredType(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer.transformClassType(JTransformer.java:95)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:695)
	at com.google.gwt.dev.jjs.ast.JClassType.traverse(JClassType.java:145)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:122)
	at com.google.gwt.dev.jjs.ast.JTransformer.transform(JTransformer.java:1100)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformProgram(GenerateJavaScriptAST.java:1242)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformProgram(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:943)
	at com.google.gwt.dev.jjs.ast.JProgram.traverse(JProgram.java:1248)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:122)
	at com.google.gwt.dev.jjs.ast.JTransformer.transform(JTransformer.java:1100)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST.execImpl(GenerateJavaScriptAST.java:3171)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST.exec(GenerateJavaScriptAST.java:2944)
	at com.google.gwt.dev.jjs.JavaToJavaScriptCompiler.compilePermutation(JavaToJavaScriptCompiler.java:380)
	at com.google.gwt.dev.jjs.JavaToJavaScriptCompiler.compilePermutation(JavaToJavaScriptCompiler.java:274)
	at com.google.gwt.dev.CompilePerms.compile(CompilePerms.java:198)
	at com.google.gwt.dev.ThreadedPermutationWorkerFactory$ThreadedPermutationWorker.compile(ThreadedPermutationWorkerFactory.java:50)
	at com.google.gwt.dev.PermutationWorkerFactory$Manager$WorkerThread.run(PermutationWorkerFactory.java:74)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.lang.NullPointerException: Cannot invoke "String.isEmpty()" because "actualJsName" is null
	at com.google.gwt.dev.jjs.ast.JMethod.getQualifiedJsName(JMethod.java:172)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformNewInstance(GenerateJavaScriptAST.java:1002)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformNewInstance(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:884)
	at com.google.gwt.dev.jjs.ast.JNewInstance.traverse(JNewInstance.java:73)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	... 52 more
               [ERROR] at Intro.java(36): new Rec("1")
                  com.google.gwt.dev.jjs.ast.JNewInstance
               [ERROR] at Intro.java(36): Rec r = new Rec("1")
                  com.google.gwt.dev.jjs.ast.JDeclarationStatement
               [ERROR] at Intro.java(33): {
  Rec r = new Rec("1");
  Window.alert(r.toString());
}
                  com.google.gwt.dev.jjs.ast.JBlock
               [ERROR] at Intro.java(33): {
  Rec r = new Rec("1");
  Window.alert(r.toString());
}
                  com.google.gwt.dev.jjs.ast.JMethodBody
               [ERROR] at Intro.java(22): co.intro.client.Intro (extends Object implements EntryPoint)
                  com.google.gwt.dev.jjs.ast.JClassType
               [ERROR] at Unknown(0): <JProgram>
                  com.google.gwt.dev.jjs.ast.JProgram
            [ERROR] Unrecoverable exception, shutting down
com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
	at com.google.gwt.dev.javac.CompilationProblemReporter.logAndTranslateException(CompilationProblemReporter.java:106)
	at com.google.gwt.dev.jjs.JavaToJavaScriptCompiler.compilePermutation(JavaToJavaScriptCompiler.java:461)
	at com.google.gwt.dev.jjs.JavaToJavaScriptCompiler.compilePermutation(JavaToJavaScriptCompiler.java:274)
	at com.google.gwt.dev.CompilePerms.compile(CompilePerms.java:198)
	at com.google.gwt.dev.ThreadedPermutationWorkerFactory$ThreadedPermutationWorker.compile(ThreadedPermutationWorkerFactory.java:50)
	at com.google.gwt.dev.PermutationWorkerFactory$Manager$WorkerThread.run(PermutationWorkerFactory.java:74)
	at java.base/java.lang.Thread.run(Thread.java:1583)
            [ERROR] Not all permutation were compiled , completed (0/1)
      [WARN] recompile failed
      [WARN] continuing to serve previous version

Steps to reproduce

public record Rec(String s) {
	public Rec(int i) {
		this("" + i);
	}
}

invoked like this

public void onModuleLoad() {
	Rec r = new Rec("1");
	Window.alert(r.toString());
}

Known workarounds

Don't use custom constructors

Links to further discussions

[niloc132]

Workaround:
Declare the default constructor. In this example, that would look like:

public record Rec(String s) {
        public Rec { }
	public Rec(int i) {
		this("" + i);
	}
}

Two stack traces I've identified that can come from this bug - this looks like the one reported:

Caused by: java.lang.NullPointerException: Cannot invoke "String.isEmpty()" because "actualJsName" is null
	at com.google.gwt.dev.jjs.ast.JMethod.getQualifiedJsName(JMethod.java:172)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformNewInstance(GenerateJavaScriptAST.java:1002)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformNewInstance(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:884)
	at com.google.gwt.dev.jjs.ast.JNewInstance.traverse(JNewInstance.java:73)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	... 52 more

And another that is similar, but not quite the same:

Caused by: java.lang.NullPointerException: Cannot invoke "String.isEmpty()" because "actualJsName" is null
	at com.google.gwt.dev.jjs.ast.JMethod.getQualifiedJsName(JMethod.java:172)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.dispatchToSuper(GenerateJavaScriptAST.java:920)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformMethodCall(GenerateJavaScriptAST.java:898)
	at com.google.gwt.dev.jjs.impl.GenerateJavaScriptAST$GenerateJavaScriptTransformer.transformMethodCall(GenerateJavaScriptAST.java:520)
	at com.google.gwt.dev.jjs.ast.JTransformer$JRewriterVisitor.visit(JTransformer.java:860)
	at com.google.gwt.dev.jjs.ast.JMethodCall.traverse(JMethodCall.java:265)
	at com.google.gwt.dev.jjs.ast.JVisitor.accept(JVisitor.java:127)
	... 58 more

The bug is that when being called in this way, the "super" constructor is incorrectly identified as being a native method as it has no body. I'm still working out why it has no body - it appears that either JDT doesn't emit a body for the "default" record constructor if there is a non-default constructor declared, or GWT just doesn't read it properly - but if the "default" constructor is declared or no constructors are declared at all, it will correctly have the field assignments as expected.