RFR: 8320750: Allow a testcase to run with muliple -Xlog

[David Holmes]

On Mon, 27 Nov 2023 14:30:02 GMT, Leo Korinth <lkorinth at openjdk.org> wrote:

>> Hi Leo,
>> 
>> I'm sorry but I don't understand this change. What I do know is that `-Xlog` supports multiple arguments and that it is indeed required to use at least one argument when enabling async logging or first disabling stdout/stderr logging:
>> 
>>>-Xlog:async -Xlog:gc=debug:file=gc.log -Xlog:safepoint=trace
>> 
>>>-Xlog:disable -Xlog:safepoint=trace:safepointtrace.txt
>> 
>> What exactly happens to a testcase which requires two arguments? I guess that we have none, as these would have crashed?
>
>> What exactly happens to a testcase which requires two arguments? I guess that we have none, as these would have crashed?
> 
> correct.
> 
> This bug is introduce by me in https://bugs.openjdk.org/browse/JDK-8317228 where I added support to `@require` on `-X` flags. If someone is running a test case and manually adds multiple JAVA_OPTIONS of the same type: `-Xlog:async -Xlog:gc=debug:file=gc.log -Xlog:safepoint=trace` It would crash.

Whoa! @lkorinth [8317228](https://github.com/openjdk/jdk/pull/15986#top) needed broader discussion for the changes to VMProps.java - what exactly is that change doing?

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PR Comment: https://git.openjdk.org/jdk/pull/16824#issuecomment-1828690719