[FLINK-35803][checkpoint] Fix the wrong file reuse in cp file-merging

[Zakelly]

What is the purpose of the change

There is an issue of reusing wrong restored files in following cp when enabling file-merging. All the files from previous job should not be reused afterwards. This PR fixes that.

Brief change log

• When creating/referencing a PhysicalFile during recovery, mark it unable to reuse.

Verifying this change

This change is already covered by existing IT tests, such as ResumeCheckpointManuallyITCase.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: yes
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• c9c1af6 Azure: SUCCESS

Bot commands

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• @flinkbot run azure re-run the last Azure build

[1996fanrui]

Thanks @Zakelly for the quick fix~

I run ResumeCheckpointManuallyITCase localy multilple times with this PR, it works well.

LGTM assuming the CI is green.

[fredia]

Thanks for the PR, couldReuse does have a problem, the fix is LGTM.

But for the failed test testSwitchFromEnablingToDisablingFileMerging, the check fail at 3rd checkpoint, I think it has something to do with the test itself.

When restoring a job from file-merging disabled to file-merging disabled in CLAIM mode, the restored state handle may be reused by the subsequent checkpoint, it is uncertain when the restored files will actually be deleted.

Update: I found that the test itself is fixed in #25066 🚀