test: stabilize sync_diff_inspector checkpoint test

[joechenrh]

What problem does this PR solve?

Issue Number: close #12553

What is changed and how it works?

The checkpoint integration test (checkpoint/run.sh) was flaky because it pre-computed a bucket_index_right (or bucket_index_left-bucket_index_right) from the last run and then used check_contains_regex to match a full indexCode pattern in the resumed run's first chunk. When chunks are created in parallel, multiple resumed chunks can share the same lower bound, so the selected first chunk may carry a different—but equally valid—indexCode, causing the regex match to fail nondeterministically.

Changes (bucket splitter, cases 1 & 2):

• Removed the pre-computed bucket_index_right/bucket_index_left variables that were derived from the previous run's index.
• Instead of matching the entire indexCode string with a regex, we now parse the resumed first chunk's indexCode into an array and assert only the structurally stable fields:
  • Case 1 (last chunk in bucket): after resuming, the next chunk must start a new bucket, so we assert chunkIndex == 0.
  • Case 2 (middle of bucket): the next chunk must be the immediate successor within the same bucket, so we assert chunkIndex == lastChunkIndex + 1 and chunkCount == lastChunkCount.

Changes (random splitter, case 1):

• Removed the check_contains_regex assertion on indexCode entirely, because the random splitter may re-split the remaining range after resuming, making the indexCode unstable across runs.
• We still assert that the resumed chunk's bound matches the last chunk's upper bound, which is the meaningful invariant.

Check List

Tests

• Integration test

Questions

Will it cause performance regression or break compatibility?

No. This is a test-only change.

Do you need to update user documentation, design documentation or monitoring documentation?

No.

Release note

None

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[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request stabilizes the sync_diff_inspector checkpoint test by refactoring how chunk indices are validated. It moves away from brittle regex-based assertions to more explicit shell array parsing and direct comparisons, making the test more resilient to variations in chunk generation and resumption logic, particularly for random splitters.

Highlights

• Improved Chunk Index Validation: Replaced regex-based checks for first_chunk_index with more robust shell array parsing and direct index comparisons, enhancing test stability.
• Removed Redundant Bucket Index Logic: Eliminated unnecessary calculations and echoes for bucket_index_right and bucket_index_left that were previously used for regex assertions.
• Adjusted Random Splitter Test: Removed a strict regex assertion for indexCode in the continuous checkpoint test, acknowledging that the random splitter's indexCode may not be stable across runs.

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Changelog

• sync_diff_inspector/tests/sync_diff_inspector/checkpoint/run.sh
  • Removed unused bucket_index_right and bucket_index_left variable assignments and echo statements.
  • Refactored first_chunk_index parsing from regex to shell array manipulation for more precise validation.
  • Updated chunk index validation logic to use direct array element comparisons instead of regex patterns.
  • Removed a specific regex check for first_chunk_index in the continuous checkpoint test, adding a comment about the instability of indexCode for random splitters.

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[gemini-code-assist]

Code Review

This pull request aims to stabilize a checkpoint test by replacing brittle regex checks with more robust parsing and assertions in a shell script. The changes are a good improvement. I've suggested a couple of refactorings to simplify the new parsing logic and remove leftover debugging code, making the script cleaner and more idiomatic.

[joechenrh]

/severity minor
/type bug

[joechenrh]

Makes sense, simplified both blocks in joechenrh@9b0ed66 . Replaced with a single IFS=: read -r -a and dropped the debug loops.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 53.3562%. Comparing base (d16456b) to head (9b0ed66).
⚠️ Report is 2 commits behind head on master.
✅ All tests successful. No failed tests found.

❌ Your project check has failed because the head coverage (53.3562%) is below the target coverage (60.0000%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

Components	Coverage Δ
cdc	57.3045% <ø> (∅)
dm	49.0888% <ø> (+0.0207%)	⬆️
engine	50.6941% <ø> (ø)

Flag	Coverage Δ
cdc	57.3045% <ø> (?)
unit	53.3562% <ø> (+3.8804%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

@@               Coverage Diff                @@
##             master     #12559        +/-   ##
================================================
+ Coverage   49.4757%   53.3562%   +3.8804%     
================================================
  Files           486       1010       +524     
  Lines         70677     139860     +69183     
================================================
+ Hits          34968      74624     +39656     
- Misses        32951      59624     +26673     
- Partials       2758       5612      +2854     

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[ti-chi-bot]

@joechenrh: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-check	9b0ed66	link	true	/test pull-check
pull-dm-integration-test	9b0ed66	link	true	/test pull-dm-integration-test

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