[crac] RFR: 8365484: [CRaC] Support IgnoreUnrecognizedVMOptions on restore

[Anton Kozlov]

On Wed, 20 Aug 2025 12:52:59 GMT, Timofei Pushkin <tpushkin at openjdk.org> wrote:

>> Not doing this should not lead to any errors in the current JVM code but I decided to do this because updating `IgnoreUnrecognizedVMOptions` may make the state of the restored VM somewhat inconsistent.
>> 
>> Suppose `IgnoreUnrecognizedVMOptions` was true on checkpoint and an unrecognized option was used in the command line. Then suppose `IgnoreUnrecognizedVMOptions` was set to false on restore. In such case after restore the command line (which I believe can be read via management or JVM TI) will contain unrecognized options while `IgnoreUnrecognizedVMOptions` will be false.
>
> I actually was not sure if this is needed or not. If you are against this, I'll remove it (i.e. make the option forwardable).

I see, thanks for the example. Right now, it also has an inconsistency. Suppose you enable it for the restore, and provide nonsense argument. The IgnoreUnrecognizedVMOptions took effect, you can sense unrecognized argument, but you check IgnoreUnrecognizedVMOptions and it's false.

I would prefer to remove special handling for the IgnoreUnrecognizedVMOptions, it will make things a bit more straightforward.

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PR Review Comment: https://git.openjdk.org/crac/pull/263#discussion_r2288102399