perf(gate): intersect changed lines via smaller-side lookup in js gate

[seonghobae]

Summary

Smaller-side lookup for Istanbul changed-line intersection in scripts/ci/javascript_coverage_gate.py: small spans probe the changed set (O(span)), large spans scan it (O(C)). Same semantics, ~96% faster on synthetic 2000x2000.

Metric (KPI: mean <=0.055s, >=40% down + guardrails)

• Baseline (main f578d8d): changed_metric_counts 2000x2000 5x mean=0.0924s (stdev 0.0113); intersects micro 2000 calls 0.0845s
• Exact-head (ba07a8c): 5x mean=0.0034s; micro 0.0019s (~96% down)
• Independent repeats: 0.0054 / 0.0213 / 0.0028, all below baseline
• Equivalence: statements (2000,2000) assert held every run

Guardrails (all GREEN, exact-head)

• Targeted: 26 passed (tests/test_javascript_coverage_gate.py, +1 new small-span test)
• Full suite: 3032 passed, 1 skipped, 21 subtests passed
• Coverage: 100% (13216 stmts / 5340 branch; changed file 261/120)
• Interrogate: 100%
• No open-PR contention: touched files absent from 20-PR name-only census (codeql_sarif_gate/filter_gitleaks/scheduler/router untouched)

Change (15+/8-, 2 files)

• scripts/ci/javascript_coverage_gate.py: _range_intersects_changed() helper + 4 call sites (intersects + 3x changed_metric_counts)
• tests/test_javascript_coverage_gate.py: test_small_span_intersection_uses_membership_lookup (covers span<len branch)

Gap linkage

• G-04 queue hygiene (gate overhead down), G-09 green CI with accuracy (output equivalence asserted). Control-plane only; no product/Buyer/DB/UX scope. Figma N/A.

Verification

• Commands: PYTHONPATH=. .venv/bin/python /tmp/baseline_js_gate.py; pytest tests/test_javascript_coverage_gate.py; coverage run -m pytest tests; coverage report; interrogate
• results.tsv experiment 6 keep (untracked, local only)

Summary by CodeRabbit

• 리팩터링

  • 코드 실행 범위와 변경된 줄의 교차 여부 판정을 공통 로직으로 정리했습니다.
  • 기존과 동일한 교차 판정 동작을 유지하면서 작은 범위를 우선 확인하도록 개선했습니다.

• 테스트

  • 실행 범위가 변경된 줄과 교차하는 경우와 교차하지 않는 경우를 검증하는 테스트를 추가했습니다.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: e76937f9-dc26-4b27-aac4-1dc9030d7dfd

📥 Commits

Reviewing files that changed from the base of the PR and between f578d8d and ba07a8c.

📒 Files selected for processing (2)

• scripts/ci/javascript_coverage_gate.py
• tests/test_javascript_coverage_gate.py

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

커버리지 게이트가 범위 길이와 변경 라인 수 중 더 작은 쪽을 순회하도록 공통 헬퍼를 사용합니다. Statement, function, branch 검사에 헬퍼를 적용하고 작은 범위의 교차 여부 테스트를 추가합니다.

Changes

커버리지 범위 교차 검사

Layer / File(s)	Summary
교차 검사 헬퍼 통합 scripts/ci/javascript_coverage_gate.py	_range_intersects_changed를 추가했습니다. intersects와 statement, function, branch 필터링이 공통 헬퍼를 사용합니다.
교차 검사 동작 테스트 tests/test_javascript_coverage_gate.py	작은 범위가 변경 라인과 교차하는 경우와 교차하지 않는 경우를 검증합니다.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to ba07a

This change optimizes changed-line coverage intersection while preserving statement, function, and branch results. Existing tests cover intersecting and non-intersecting short ranges, with no current merge-blocking risk identified.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	제목은 변경된 줄과 범위의 교집합을 더 작은 쪽에서 조회하도록 최적화한 핵심 변경을 정확하고 간결하게 설명합니다.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch autoresearch/20260910-js-gate-intersect

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