fix(review): scan patch-less PR files for leaked secrets

[RealDiligent]

Problem

GitHub omits inline patch for binary/large PR files; the unconditional secret_leak gate only scanned inline diff + lines, so credentials in patch-less files could bypass the hard blocker.

Fix

• src/queue/patchless-secret-scan.ts — fetch head/base via Contents API, synthesize scannable + lines, fail closed on oversized/unfetchable content.
• Wired into maybeAddSecretLeakFinding at gate time.

Pre-PR validation

• npm run typecheck
• test/unit/patchless-secret-scan.test.ts (41 tests, 100% patch coverage locally)

Supersedes closed #3473 (codecov passed but auto-closed without merge).

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[loopover-orb]

Caution

🟥🟥🟥🟥🟥🟥🟥🟥🟥🟥🟥🟥

🛑 Gittensory review result - reject/close recommended

_{Review updated: 2026-07-05 09:24:33 UTC}

3 files · 1 AI reviewer · 1 blocker · readiness 80/100 · CI pending · blocked

🛑 Suggested Action - Reject/Close

• AI reviewers agree on a likely critical defect: src/queue/patchless-secret-scan.ts:128 passes SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS as the fetch limit and then checks `headContent.length > SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS`, but the existing grounding caller uses `limit + 1` specifically to detect truncation, so a real oversized patch-less file can be truncated to exactly 512000 chars, treated as complete, and hide a secret after the cap
• change the head/base fetches to request `SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS + 1` before the existing `isOverSecretScanContentLimit` checks. — Resolve the flagged defect, or override if the AI reviewers are mistaken, then re-run the gate.

Review summary
This change wires a patch-less file fallback into the deterministic secret scan and the main flow is pointed at the right gate path: it fetches head/base content, synthesizes added lines, and emits a critical finding when content cannot be fully scanned. The important correctness gap is at the fetch boundary: the new code tests an oversized branch that the real fetcher contract may never expose because it passes the scan cap as the fetch limit instead of cap+1, so secrets after the cap can still be hidden in a large patch-less file. The PR also only references a closed superseded PR, not an eligible open issue, which violates this repo's contributor-scope requirement.

Blockers

• src/queue/patchless-secret-scan.ts:128 passes SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS as the fetch limit and then checks `headContent.length > SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS`, but the existing grounding caller uses `limit + 1` specifically to detect truncation, so a real oversized patch-less file can be truncated to exactly 512000 chars, treated as complete, and hide a secret after the cap; change the head/base fetches to request `SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS + 1` before the existing `isOverSecretScanContentLimit` checks.
• PR description: the only linked reference is closed fix(review): scan patch-less PR files for leaked secrets #3473, but this repo requires external contributor PRs to close or clearly link an eligible open issue, so link the open maintainer-authorized issue this fixes or explain why this is maintainer-authorized.

Nits — 5 non-blocking

• test/unit/patchless-secret-scan.test.ts:424 fabricates a real fetcher returning 512001 chars even though the production fetch limit is currently 512000, so that test covers the intended branch without proving the actual Contents API path reaches it.
• src/queue/patchless-secret-scan.ts:79 includes every incomplete path verbatim in one finding detail, which can become noisy on a PR with many patch-less generated files; consider capping the displayed list while keeping the count exact.
• src/queue/patchless-secret-scan.ts:128,143,153 should mirror the existing full-file grounding pattern: `const fetchLimit = SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS + 1;` and pass `fetchLimit` to every `getFileContent` call, then keep `isOverSecretScanContentLimit` as the fail-closed detector.
• test/unit/patchless-secret-scan.test.ts:424 should assert the fetcher receives `512001` and returns a `512001`-char body so the oversized test exercises the real production contract instead of an impossible mocked payload.
• PR description should add the eligible open issue link in the closing format expected by the maintainer gate.

Why this is blocked

• src/queue/patchless-secret-scan.ts:128 passes SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS as the fetch limit and then checks `headContent.length > SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS`, but the existing grounding caller uses `limit + 1` specifically to detect truncation, so a real oversized patch-less file can be truncated to exactly 512000 chars, treated as complete, and hide a secret after the cap; change the head/base fetches to request `SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS + 1` before the existing `isOverSecretScanContentLimit` checks.

Signal	Result	Evidence
Code review	❌ 1 blocker	1 reviewer
Linked issue	✅ Linked	#3473
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (1 linked issue).
Validation posture	❌ 5/25	Preflight is holding this PR: the review lane is unavailable, so it is not ready for automated review.
Contributor workload	✅ 10/10	Author activity: 138 registered-repo PR(s), 18 merged, 0 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	RealDiligent; Gittensor profile; 138 PR(s), 0 issue(s).
Gate result	❌ Blocking	Repo-configured hard blocker found.

Review context

• Author: RealDiligent
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository registration is not available in the local Gittensory cache.
• Public profile languages: Ruby, Svelte, TypeScript, Cuda, JavaScript, Markdown
• Official Gittensor activity: 138 PR(s), 0 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Await review-lane availability.
• Refresh registry data or choose a registered active repo.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed}

---

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Checked by Gittensory, a quiet PR intelligence layer for OSS maintainers.

• Re-run Gittensory review

[loopover-orb]

Gittensory is closing this pull request on the maintainer's behalf (AI reviewers agree on a likely critical defect: src/queue/patchless-secret-scan.ts:128 passes SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS as the fetch limit and then checks `headContent.length > SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS`, but the existing grounding caller uses `limit + 1` specifically to detect truncation, so a real oversized patch-less file can be truncated to exactly 512000 chars, treated as complete, and hide a secret after the cap; change the head/base fetches to request `SECRET_SCAN_PATCH_FALLBACK_MAX_CHARS + 1` before the existing `isOverSecretScanContentLimit` checks.). This is an automated maintenance action — to pursue this change, please open a new pull request with the issues resolved. Closed PRs may be analyzed later to improve review accuracy, but they are not automatically reopened or re-reviewed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.05%. Comparing base (a979552) to head (50a8bb1).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3481      +/-   ##
==========================================
+ Coverage   93.03%   93.05%   +0.01%     
==========================================
  Files         298      299       +1     
  Lines       31203    31281      +78     
  Branches    11386    11414      +28     
==========================================
+ Hits        29029    29107      +78     
  Misses       1518     1518              
  Partials      656      656              

Files with missing lines	Coverage Δ
src/queue/patchless-secret-scan.ts	100.00% <100.00%> (ø)
src/queue/processors.ts	93.40% <100.00%> (+0.02%)	⬆️

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