On Thu, 20 Jul 2023 01:04:08 GMT, Mandy Chung <mch...@openjdk.org> wrote:
>> `VarForm::getMemberName` currently throws UOE with no information if the
>> requested access mode is unsupported. To provide the var handle
>> information, move the access mode check to `VarHandle` so that the exception
>> message can include the var handle information. Changes include:
>>
>> 1. change `VarHandle::checkAccessModeThenIsDirect` to check if the access
>> mode is unsupported. This check is only needed for direct var handle.
>> 2. change `VarHandle::getMethodHandleUncached` to call `getMemberNameOrNull`
>> and throw UOE with an informative exception message if the access mode is
>> unsupported
>>
>> The error message looks like:
>>
>> java.lang.UnsupportedOperationException: compareAndSet is not supported for
>> VarHandle[varType=java.lang.String, coord=[class Foo$Goo]]
>
> Mandy Chung has updated the pull request incrementally with one additional
> commit since the last revision:
>
> update copyright header
src/java.base/share/classes/java/lang/invoke/VarHandle.java line 2010:
> 2008: static AccessMode valueFromOrdinal(int mode) {
> 2009: return VALUES[mode];
> 2010: }
Also, I'll throw this out there, though I'm not sure how big of an issue it is:
this array creation might have an effect on startup. But, since it is only used
on a slow path right before we throw an exception (at least, at the moment),
calling `values()` every time inside the `valueFromOrdinal` method, and
avoiding the array creation on startup, might be 'better'.
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PR Review Comment: https://git.openjdk.org/jdk/pull/14928#discussion_r1269616973
