RFR: JDK-8315575: Retransform of record class with record component annotation fails with CFE [v5]

[Serguei Spitsyn]

On Thu, 21 Mar 2024 05:02:17 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> Instrumentation.retransformClasses logic can be described by the following pseudo-code:
>> 
>> byte[] newClassBytes = JvmtiClassFileReconstituter.reconstitute(klass);
>> for (Transformer tr = firstTransformer(); tr != null; tr = tr->next()) {
>>   byte[] transformerClassBytes = tr.transform(newClassBytes);
>>   if (newClassBytes != null) {
>>     newClassBytes = transformerClassBytes;
>>   }
>> }
>> 
>> Then newClassBytes is parsed, verified and is used to redefine the class.
>> 
>> We need to verify that JvmtiClassFileReconstituter produces correct class bytes, so test transformer can return null or passed classfileBuffer.
>> Actually the issue can be reproduced without ClassFileTransformer at all (and this is mentioned in the CR) - in the case reconstituted class bytes is considered as a result of the instrumentation.
>> 
>> I've updated the test, hope it's clearer now.
>> `targetClassName`/`seenClassBytes`/`newClassBytes` was used by Transformer, I moved them to the class.
>> Please let me know if you think some additional comments would be useful.
>
> Thank you for the update, it is a nice change.
> I'd also suggest to add a comment before line 115, something like this:
> 
>   // Below the null is passed as the classBytes argument which means there won't be any transformation.
>   // However, it is enough for testing purposes as the JvmtiClassFileReconstituter still involved
>   // into preparation of the initial classfile bytecodes.

Thank you for the update.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18161#discussion_r1534563753