[GROOVY-7921] using "this" as the target of an assignment not working with Category annotation

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.7
• Fix Version/s: 2.4.8
• Environment: mac os x 10.10.5; jdk 1.8.0_51
• Assignee: Paul King
• Reporter: kyon_mm
• Created: 27/Aug/16 15:42
• Updated: 01/Feb/17 23:18
• Resolved: 31/Aug/16 02:45

Description

when I executed this code in GroovyConsole

@Category(Integer)
class IntegerEx {
  def reset(int value) {
    this = value
    this
  }
}
use(IntegerEx){
  println (1 + 2).reset(1)
}

Then, I get this exception log

Exception thrown

BUG! exception in phase 'semantic analysis' in source unit 'ConsoleScript17' null
	at org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:935)
	at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:593)
	at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:542)
	at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:298)
	at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:268)
	at groovy.lang.GroovyShell.parseClass(GroovyShell.java:688)
	at groovy.lang.GroovyShell.run(GroovyShell.java:517)
	at groovy.lang.GroovyShell.run(GroovyShell.java:497)
	at groovy.lang.GroovyShell.run(GroovyShell.java:170)
	at groovy.lang.GroovyShell$run$1.call(Unknown Source)
	at groovy.ui.Console$_runScriptImpl_closure16.doCall(Console.groovy:1005)
	at groovy.ui.Console$_runScriptImpl_closure16.doCall(Console.groovy)
	at sun.reflect.GeneratedMethodAccessor218.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
	at groovy.lang.Closure.call(Closure.java:414)
	at groovy.lang.Closure.call(Closure.java:408)
	at groovy.lang.Closure.run(Closure.java:495)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
	at org.codehaus.groovy.classgen.VariableScopeVisitor.checkForFinal(VariableScopeVisitor.java:388)
	at org.codehaus.groovy.classgen.VariableScopeVisitor.checkFinalFieldAccess(VariableScopeVisitor.java:381)
	at org.codehaus.groovy.classgen.VariableScopeVisitor.visitBinaryExpression(VariableScopeVisitor.java:365)
	at org.codehaus.groovy.ast.expr.BinaryExpression.visit(BinaryExpression.java:51)
	at org.codehaus.groovy.ast.CodeVisitorSupport.visitExpressionStatement(CodeVisitorSupport.java:71)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitExpressionStatement(ClassCodeVisitorSupport.java:196)
	at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:42)
	at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:37)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:166)
	at org.codehaus.groovy.classgen.VariableScopeVisitor.visitBlockStatement(VariableScopeVisitor.java:308)
	at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:71)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:104)
	at org.codehaus.groovy.classgen.VariableScopeVisitor.visitConstructorOrMethod(VariableScopeVisitor.java:505)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:126)
	at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1078)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:53)
	at org.codehaus.groovy.classgen.VariableScopeVisitor.visitClass(VariableScopeVisitor.java:473)
	at org.codehaus.groovy.control.CompilationUnit$11.call(CompilationUnit.java:648)
	at org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:931)
	... 22 more

Is this behavior groovy-language specification ?

Issue Links

• relates to: GROOVY-6947 NPE in compilation when assigning a value to 'this'
• links to: GitHub Pull Request #400