[crac] RFR: 8364538: [CRaC] Test CRaCIgnoreRestoreIfUnavailable [v2]

[Timofei Pushkin]

On Mon, 4 Aug 2025 15:16:00 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

>> Timofei Pushkin has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix EngineFailureTest on linux-x86
>
> test/jdk/jdk/crac/ignoreRestore/EngineFailureTest.java line 55:
> 
>> 53:             .startCheckpoint().waitForSuccess();
>> 54: 
>> 55:         new CracBuilder()
> 
> The `crexec` option for `CRaCEngine` is weird; looks like a leftover from times when we had `CREngineLibrary` as well. Is it supposed to execute CRIU, or completely fail the restore, leading to 'unavailable'?

There is a long comment above explaining why this is done like this. Basically we need the failure to happen before `exec`ing the engine executable because there is no return to the parent VM from there.

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PR Review Comment: https://git.openjdk.org/crac/pull/255#discussion_r2253333276