Fix unbounded job.Status.Conditions growth

[avinxshKD]

What type of PR is this?

/kind bug

What this PR does / why we need it:

This PR fixes an issue where job.Status.Conditions grows unbounded during frequent job phase transitions (especially for jobs with RestartJob policies that retry often). Previously, every phase transition unconditionally appended a new condition without deduplication or a maximum length check.

For heavily retried jobs, this slice could easily accumulate thousands of entries, eventually causing the UpdateStatus call to permanently fail with etcdserver: request is too large. At this point, the job becomes unrecoverable without manual deletion.

This fix introduces an appendJobCondition helper that:

1. Skips appending if the new condition's phase is identical to the most recent one (deduplicating redundant consecutive states).
2. Enforces a hard cap of maxJobConditions = 32, truncating the oldest entries to ensure the etcd object size remains bounded and safe.

Which issue(s) this PR fixes:

Fixes #5421

Special notes for your reviewer:

The maxJobConditions is set to 32, which is more than enough to capture the recent historical context of a job's state transitions without risking etcd size limits.

Does this PR introduce a user-facing change?

Fixed an issue where frequently restarting jobs could exceed etcd object size limits by capping `job.Status.Conditions` to a maximum of 32 entries and deduplicating consecutive identical phases.

[volcano-sh-bot]

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[volcano-sh-bot]

Welcome @avinxshKD! It looks like this is your first PR to volcano-sh/volcano 🎉

[gemini-code-assist]

Code Review

This pull request limits the number of job conditions stored in job.Status.Conditions to a maximum of 32 to prevent unbounded growth in etcd. It introduces the appendJobCondition helper function to handle deduplication of consecutive identical phases and truncation of older entries, accompanied by unit tests. The review feedback points out a potential memory leak in the truncation logic, where slicing the slice from the front keeps discarded pointers pinned in memory, and suggests copying the remaining elements to a new slice instead.

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[avinxshKD]

@JesseStutler Just a quick note on this one: the core fix is very minimal. The bulk of the lines added here are just the new unit tests in job_controller_actions_test.go to ensure the truncation and deduplication work exactly as expected.

Happy to make any adjustments to the cap size or logic if needed, thanks

[avinxshKD]

@hzxuzhonghu lgtm, happy to make any further changes if needed thanks.

[hzxuzhonghu]

THis is not right. You should use a loop and match delete the original condition and append the new condition at last

[avinxshKD]

I've rewritten the logic exactly as requested, it now loops through to filter out any existing condition with the matching phase, and appends the new one at the end.

Tests are updated and passingg