[GROOVY-9482] Problem with empty case in switches when not in last position

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 2.5.10
• Component/s: syntax
• Environment: openjdk version "1.8.0_242" (zulu)
• Assignee: Unassigned
• Reporter: Sylvain Dusart
• Created: 27/Mar/20 10:22
• Updated: 27/Mar/20 11:39
• Resolved: 27/Mar/20 11:39

Description

There seems to be a problem with empty cases for switch with groovy 2.5.10 except when they are in the last position.

String s = ''

switch (s) {

  case 'a':
  	println s
	break

  // will generate a compilation error with groovy 2.5.10
  case 'empty':
        break

  case 'b':
        println s
	break
}

The exception is :

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:General error during class generation: org.codehaus.groovy.ast.stmt.ReturnStatement cannot be cast to org.codehaus.groovy.ast.stmt.BlockStatement
java.lang.ClassCastException: org.codehaus.groovy.ast.stmt.ReturnStatement cannot be cast to org.codehaus.groovy.ast.stmt.BlockStatement at org.codehaus.groovy.classgen.FinalVariableAnalyzer.fallsThrough(FinalVariableAnalyzer.java:480) at org.codehaus.groovy.classgen.FinalVariableAnalyzer.visitSwitch(FinalVariableAnalyzer.java:344) at org.codehaus.groovy.ast.stmt.SwitchStatement.visit(SwitchStatement.java:53) at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:86) at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:106) at org.codehaus.groovy.classgen.FinalVariableAnalyzer.visitBlockStatement(FinalVariableAnalyzer.java:147) at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69) at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:110) at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:121) at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:132) at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1103) at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:54) at org.codehaus.groovy.classgen.Verifier.checkFinalVariables(Verifier.java:263) at org.codehaus.groovy.classgen.Verifier.visitClass(Verifier.java:258) at org.codehaus.groovy.control.CompilationUnit$18.call(CompilationUnit.java:811) at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1084) at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:640) at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:618) at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:595) at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:401) at groovy.lang.GroovyClassLoader.access$300(GroovyClassLoader.java:89) at groovy.lang.GroovyClassLoader$5.provide(GroovyClassLoader.java:341) at groovy.lang.GroovyClassLoader$5.provide(GroovyClassLoader.java:338) at org.codehaus.groovy.runtime.memoize.ConcurrentCommonCache.getAndPut(ConcurrentCommonCache.java:147) at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:336) at groovy.lang.GroovyShell.parseClass(GroovyShell.java:546) at groovy.lang.GroovyShell.run(GroovyShell.java:375) at groovy.lang.GroovyShell.run(GroovyShell.java:365) at groovy.ui.GroovyMain.processOnce(GroovyMain.java:592) at groovy.ui.GroovyMain.run(GroovyMain.java:336) at groovy.ui.GroovyMain.access$1400(GroovyMain.java:69) at groovy.ui.GroovyMain$GroovyCommand.process(GroovyMain.java:295) at groovy.ui.GroovyMain.processArgs(GroovyMain.java:134) at groovy.ui.GroovyMain.main(GroovyMain.java:116) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.codehaus.groovy.tools.GroovyStarter.rootLoader(GroovyStarter.java:110) at org.codehaus.groovy.tools.GroovyStarter.main(GroovyStarter.java:128)
1 error 

It works with groovy 2.5.9 and 3.0.2.

In attachment, you'll find a small test case to reproduce the problem.

Issue Links

• duplicates: GROOVY-9438 Incorrect handling of particular case statements within switch