[jboss-jira] [JBoss JIRA] (JASSIST-165) VerifyError with addLocalVariable() and insertAfter() when the method body is in a try catch statement

[Hua Zhang (JIRA)]

    [ https://issues.jboss.org/browse/JASSIST-165?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12682401#comment-12682401 ] 

Hua Zhang commented on JASSIST-165:
-----------------------------------

I find the solution.
Change "theMethod.insertBefore("{long __t = System.nanoTime();}");" to 
"theMethod.insertBefore("{__t = System.nanoTime();}");"
It works.
It seems a Compile Exception should be thrown since double defining __t.

 
 
                
> VerifyError with addLocalVariable() and insertAfter() when the method body is in a try catch statement
> ------------------------------------------------------------------------------------------------------
>
>                 Key: JASSIST-165
>                 URL: https://issues.jboss.org/browse/JASSIST-165
>             Project: Javassist
>          Issue Type: Bug
>    Affects Versions: 3.16.1-GA
>         Environment: JDK 1.6, javassist3.16.1_GA
>            Reporter: Hua Zhang
>            Assignee: Shigeru Chiba
>            Priority: Blocker
>
> CtClass cc = pool.get(className);
> CtMethod theMethod = ...;
> cc.defrost();
> theMethod.addLocalVariable("__t", pool.get("long"));
> theMethod.insertBefore("{long __t = System.nanoTime();}");
> theMethod.insertAfter("{System.out.println(System.nanoTime() - __t);}");
> cc.freeze();
> byte[] classFile = cc.toBytecode();
> swapper.reload(className, classFile); // swapper is javassist.util.HotSwapper
> This code snippet can work for the method which doesn't contain try catch statement. However, if the method likes this:
> public void method(...) {
>     try {
>         ......
>     } catch (Exception e) {
>     }
> }
> Error thrown:
> Exception in thread "HotSwap" java.lang.VerifyError: verifier detected internal
> inconsistency or security problem
> It is because __t is not visible in insertAfter() in this case. If modify the statement "theMethod.insertAfter("{System.out.println(System.nanoTime() - __t);}");" to be "theMethod.insertAfter("{System.out.println(System.nanoTime());}");" ( it removes the reference to variable __t), the code can work properly.
> Note I use insertAfter(String), not insertAfter(String, true).

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