[fix](regression) Stabilize variant hirachinal array output

[eldenmoon]

What problem does this PR solve?

Issue Number: None

Related PR: None

Problem Summary: Stabilize the variant predefine hirachinal regression output by serializing v['c'] through JSON instead of relying on variant string formatting, which can differ in insignificant array whitespace.

Release note

None

Check List (For Author)

• Test: Regression test
  • ./run-regression-test.sh --run --conf tmp/regression-conf.auto.groovy -d variant_p0/predefine -s regression_test_variant_predefine_hirachinal -forceGenOut
  • ./run-regression-test.sh --run --conf tmp/regression-conf.auto.groovy -d variant_p0/predefine -s regression_test_variant_predefine_hirachinal
• Behavior changed: No
• Does this need documentation: No

[eldenmoon]

run buildall

[eldenmoon]

run buildall

[Copilot]

Pull request overview

Stabilizes the regression output for the “variant hirachinal” predefined test by avoiding Variant-to-string formatting differences (notably insignificant whitespace in arrays) and instead serializing v['c'] via JSON.

Changes:

• Update regression queries to use cast(v['c'] as json) instead of cast(v['c'] as string).
• Regenerate the expected .out file to reflect the stable JSON serialization output (e.g., [1,2,3]).

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
regression-test/suites/variant_p0/predefine/variant_hirachinal.groovy	Switches v['c'] serialization in test queries from string formatting to JSON casting for stable output.
regression-test/data/variant_p0/predefine/variant_hirachinal.out	Updates expected results to match JSON serialization formatting (removes array whitespace variance).

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[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[eldenmoon]

/review

[github-actions]

Review conclusion: no additional blocking issues found in this PR. The diff is narrowly scoped to stabilizing one variant regression query by casting the selected sub-value to JSON and updating the generated expected output accordingly. I did not duplicate the already-open inline thread about using var_rs instead of ${table_name}.

Critical checkpoint conclusions:

• Goal/test proof: The stated goal is to avoid insignificant variant string-format whitespace differences in regression_test_variant_predefine_hirachinal; the query/output changes match that goal, and the PR reports both force-generating and rerunning the focused regression test. CI regression checks are passing.
• Scope/focus: The change is small and limited to the affected regression suite and .out file.
• Concurrency/lifecycle/config/compatibility/persistence/data-write concerns: Not applicable; this is regression test SQL/output only.
• Parallel paths: Similar variant hierarchy suites still use string casts, but this PR targets the predefine suite output instability specifically; no distinct correctness issue found from that alone.
• Test coverage/results: The expected output is consistent with JSON serialization for the changed query. No additional user-provided focus points were present.
• Observability/performance: Not applicable for this test-only change.