[GROOVY-5756] error during class generation: cannot define closures inside methods of an enum instance

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.5
• Fix Version/s: 2.1.3, 2.2.0-beta-1
• Environment: Mac OS X 10.7.5, IntelliJ IDEA 11.1.3
• Assignee: Paul King
• Reporter: Balazs Zagyvai
• Created: 11/Oct/12 18:38
• Updated: 12/Apr/13 16:55
• Resolved: 26/Mar/13 05:30

Description

The following code fails to run:

enum MyEnum {
    INSTANCE {
        String foo() {
            def clos = {
                "foo"
            }
            clos.call()
        }
    }

    String foo() {
    }
}

assert "foo" == MyEnum.INSTANCE.foo()

The Groovy runtime throws the following exception when trying to execute it:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
General error during class generation: NPE while processing ClosureDefiningEnumInstanceMethodTest.groovy

groovy.lang.GroovyRuntimeException: NPE while processing ClosureDefiningEnumInstanceMethodTest.groovy
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitClass(AsmClassGenerator.java:198)
	at org.codehaus.groovy.control.CompilationUnit$14.call(CompilationUnit.java:786)
	at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1027)
	at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:564)
	at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:542)
	at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:519)
	at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:279)
	at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:258)
	at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:244)
	at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:185)
	at groovy.lang.GroovyShell$2.run(GroovyShell.java:206)
	at groovy.lang.GroovyShell$2.run(GroovyShell.java:204)
	at java.security.AccessController.doPrivileged(Native Method)
	at groovy.lang.GroovyShell.run(GroovyShell.java:204)
	at groovy.lang.GroovyShell.run(GroovyShell.java:150)
	at groovy.ui.GroovyMain.processOnce(GroovyMain.java:557)
	at groovy.ui.GroovyMain.run(GroovyMain.java:344)
	at groovy.ui.GroovyMain.process(GroovyMain.java:330)
	at groovy.ui.GroovyMain.processArgs(GroovyMain.java:119)
	at groovy.ui.GroovyMain.main(GroovyMain.java:99)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.codehaus.groovy.tools.GroovyStarter.rootLoader(GroovyStarter.java:106)
	at org.codehaus.groovy.tools.GroovyStarter.main(GroovyStarter.java:128)
Caused by: java.lang.NullPointerException
	at org.codehaus.groovy.classgen.asm.ClosureWriter.createClosureClass(ClosureWriter.java:184)
	at org.codehaus.groovy.classgen.asm.ClosureWriter.getOrAddClosureClass(ClosureWriter.java:150)
	at org.codehaus.groovy.classgen.asm.ClosureWriter.writeClosure(ClosureWriter.java:77)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitClosureExpression(AsmClassGenerator.java:546)
	at org.codehaus.groovy.ast.expr.ClosureExpression.visit(ClosureExpression.java:43)
	at org.codehaus.groovy.classgen.asm.BinaryExpressionHelper.evaluateEqual(BinaryExpressionHelper.java:295)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitDeclarationExpression(AsmClassGenerator.java:522)
	at org.codehaus.groovy.ast.expr.DeclarationExpression.visit(DeclarationExpression.java:87)
	at org.codehaus.groovy.classgen.asm.StatementWriter.writeExpressionStatement(StatementWriter.java:604)
	at org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeExpressionStatement(OptimizingStatementWriter.java:354)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitExpressionStatement(AsmClassGenerator.java:509)
	at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:40)
	at org.codehaus.groovy.classgen.asm.StatementWriter.writeBlockStatement(StatementWriter.java:81)
	at org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeBlockStatement(OptimizingStatementWriter.java:155)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement(AsmClassGenerator.java:455)
	at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:101)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:112)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitStdMethod(AsmClassGenerator.java:319)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitConstructorOrMethod(AsmClassGenerator.java:276)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:123)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitMethod(AsmClassGenerator.java:396)
	at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1056)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:50)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitClass(AsmClassGenerator.java:180)
	... 25 more

1 error


As the stacktrace suggests, the problem is caused by the closure definition in the enum instance specific foo() method.