RFR: 8332124: Jcmd processing should accept the "help" sub option as command argument [v2]

[Kevin Walls]

On Tue, 25 Jun 2024 13:55:32 GMT, Sonia Zaldana Calles <szaldana at openjdk.org> wrote:

>> Hi all, 
>> 
>> This PR addresses [8332124](https://bugs.openjdk.org/browse/JDK-8332124) enabling jcmd to accept "help" as an argument to subcommands. 
>> 
>> Testing: 
>> - [x] Verified running `jcmd 4711 VM.metaspace help` works along with other subcommands. 
>> - [x] Added test case passes. 
>> 
>> Thanks, 
>> Sonia
>
> Sonia Zaldana Calles has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into JDK-8332124
>  - Adding test case for suboptions with trailing spaces and adding null terminator to reordered command
>  - 8332124: Jcmd processing should accept the "help" sub option as command argument

Thanks Thomas -

Yes I could see all of "jcmd PID XX.command -help" and -h and --help being recongised, and giving help, and ignoring anything else on the line after that.

We dont have any "--" prefixes in use, but if we can recognise it and show the help that could still be good and I don't think it can clash.

Hopefully this kind of thing can still be done without changing every implementing class. 8-)

Yes, standards...  Agreed it's a concern!... 
FYI while looking into this I was looking through the commands, and have also started:
8335154: jcmd VM.classes -verbose=false does not set verbose to false
8335169: jcmd should standardize on "-verbose" not "verbose" (ClassLoaderHierarchyDCmd and JFR.check are different to the rest)

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PR Comment: https://git.openjdk.org/jdk/pull/19776#issuecomment-2191696483