fix(review): count blank context lines in addedLinesFromPatch so blocker anchors don't drift

[shin-core]

What & why

src/review/ has two parallel unified-diff line-number walkers over the same payload.patch:
rightSideLinesFromPatch (RIGHT-side commentable lines) and addedLinesFromPatch (ADDED + lines only). #9076 fixed a line-number desync in the first and documented it inline, but addedLinesFromPatch still had the pre-#9076 code — and since #9076 it is the authoritative anchor validator for blocker-severity inline findings (inline-comments-select.ts:103) and gates every committable suggestion via isSuggestionAnchorable.

The bug: a zero-length patch line (a context line whose single leading space the split stripped → marker undefined) was continued past without advancing right, desyncing every later added-line number. On the patch "@@ -1,3 +1,3 @@\n one\n\n+three", rightSideLinesFromPatch returns {1,2,3} but addedLinesFromPatch returned {2} instead of {3}. So a correctly-anchored blocker on the added line 3 was silently dropped, and a blocker the model anchored on the blank context line 2 was accepted and posted — exactly the "telling a contributor their bug is on a line they did not write" failure #9076 exists to prevent. A second divergence: no trailing-empty-element pop, so a patch ending in a newline counted one extra line.

The fix

Mirror rightSideLinesFromPatch line-for-line:

• Drop the trailing empty split artifact before the walk (rawLines.pop() when the last element is "").
• Remove marker === undefined from the skip condition so a zero-length line falls through to right += 1 — still not added (only "+" adds), but counted as the context line it is.
• "-" / "\\" handling and the added-only semantics are unchanged; no caller signature changes; rightSideLinesFromPatch and isSuggestionAnchorable untouched.

Both walkers now agree on every line number for every patch shape.

Tests

• test/unit/inline-suggestion-anchor.test.ts (orb(review): fix addedLinesFromPatch dropping blank context lines — blocker anchors drift #9663 suite): a zero-length context line advances right so "+three" is line 3 (was 2); a trailing-newline patch yields the same set as without; "-"/"\\" stay skipped; isSuggestionAnchorable returns true for line 3 and false for the blank context line 2.
• test/unit/inline-comments.test.ts (end-to-end, Deliverable 3): selectInlineComments posts a blocker anchored on the added line 3 and drops one anchored on the blank context line 2 — the orb(ai-review): prompt-injection defang collapses newlines, shifting every inline anchor after it onto the wrong line #9076 guarantee holds across a blank context line.

Each behavior-changing case fails against main (regression-proven). Diff coverage on the changed file is 100% line and branch.

Validation

• npm run typecheck green; the three inline suites green.
• git diff --check <base> HEAD clean; diff is three files (one src + two tests), no route/schema/migration change.

Closes #9663

[superagent-security]

🚨 Contributor flagged. Click here for more info: Superagent Dashboard

[loopover-orb]

Warning

⏸️ LoopOver review result - manual review recommended

_{Review updated: 2026-07-29 08:34:30 UTC}

3 files · 1 AI reviewer · no blockers · CI green · unstable

⏸️ Suggested Action - Manual Review

Review summary
This fixes a real desync bug in `addedLinesFromPatch`: a zero-length patch line (stripped leading space on a blank context line) was previously skipped without advancing `right`, causing every subsequent added-line number to be off by one, which could cause a blocker anchored on an added line to be dropped and one on a context line to be wrongly accepted. The fix mirrors the sibling `rightSideLinesFromPatch` walker exactly (dropping the trailing empty split artifact and letting a zero-length line fall through to `right += 1` without adding it), and is well covered by targeted unit tests including an end-to-end `selectInlineComments` test demonstrating the exact anchor-drift scenario. The change is narrow, self-contained, and the tests exercise the real code path rather than a fabricated one.

Nits — 4 non-blocking

• The PR description is verbose with heavy inline comments explaining the same rationale multiple times (file and tests); could be trimmed for readability.
• No mention of an issue number being formally linked/closed in the repo's issue tracker beyond 'orb(review): fix addedLinesFromPatch dropping blank context lines — blocker anchors drift #9663' referenced in comments — worth confirming this closes an actual open issue per repo convention.
• Consider extracting the shared line-walking logic between `rightSideLinesFromPatch` and `addedLinesFromPatch` into one function to prevent this exact class of drift bug from recurring when one walker is updated without the other (src/review/inline-suggestion-anchor.ts, src/review/inline-comments.ts).
• The inline comments in the diff are lengthy for what's a fairly small, well-tested fix — could be tightened.

Decision drivers

• ✅ Code review — No blockers (1 reviewer)
• ✅ Gate result — Passing (No configured blocker found.)

Context & advisory signals — never blocks the verdict

Signal	Result	Evidence
Linked issue	✅ Linked	#9663
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: 50 registered-repo PR(s), 35 merged, 0 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	shin-core; Gittensor profile; 50 PR(s), 0 issue(s).
Improvement	✅ Minor	risk: clean · value: minor

Linked issue satisfaction

Addressed
The diff mirrors rightSideLinesFromPatch by popping the trailing empty split artifact and removing the `marker === undefined` continue so blank context lines advance `right`, matching all stated requirements. All four required tests are present: the unit test for the blank-context patch expecting {3}, the trailing-newline equivalence test, the end-to-end selectInlineComments regression test postin

Review context

• Author: shin-core
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is registered but has no active allocation in the current snapshot.
• Public profile languages: not available
• Official Gittensor activity: 50 PR(s), 0 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Start here: Await review-lane availability.
• Then work through the remaining 2 steps in the Signals table above.

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.

🧪 Chat with LoopOver

Ask LoopOver a question about this PR directly in a comment — grounded only in the same cached, public-safe facts shown above, never a new claim.

• @loopover ask <question> answers contribution-quality Q&A with source citations and freshness.
• @loopover chat <question> answers in natural prose from cached decision-pack facts via local inference (maintainer/collaborator; read-only).
• A plain-language @loopover mention with a real question is routed to the closest matching read-only command automatically — no exact syntax required.

Full command reference: https://loopover.ai/docs/loopover-commands

🧪 Experimental — new and may change.

Decision record

• action: hold · clause: success
• config: 0942b3ba452ad51b0cee5084e04ece151ff5097a479aa1b42d89a0e57d26f5b8 · pack: oss-anti-slop · ci: passed
• record: a964e479d178cb06434bfe903131a4ba8ab212edde479b230755a402fe6497bd (schema v5, head 3bd9d63)

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

---

💰 Earn for open-source contributions like this. Gittensor lets GitHub contributors earn for the work they already do — register to start earning →.

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

• Re-run LoopOver review

[superagent-security]

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.60%. Comparing base (bf654cf) to head (3bd9d63).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #9781       +/-   ##
===========================================
- Coverage   90.30%   76.60%   -13.71%     
===========================================
  Files         912      283      -629     
  Lines      113555    59494    -54061     
  Branches    26955     8488    -18467     
===========================================
- Hits       102544    45573    -56971     
- Misses       9682    13639     +3957     
+ Partials     1329      282     -1047     

Flag	Coverage Δ
backend	100.00% <100.00%> (+4.43%)	⬆️

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

Files with missing lines	Coverage Δ
src/review/inline-suggestion-anchor.ts	100.00% <100.00%> (ø)

... and 763 files with indirect coverage changes

[loopover-orb]

Held for manual review: the gate and required CI are green, but GitHub reports this pull request's mergeable state as unstable because a non-required check or status is not passing, so LoopOver will not auto-merge. A maintainer can resolve the failing check or review and merge manually. This is an automated maintenance action.