[ScottN-PV]

Native stacks can save different layer lists on different linked pull requests. Reading only the first saved list puts newly added layers before older layers and can select the wrong current PR.

Use the snapshot that covers the most linked stack members, then the longest list; ties retain the earliest stored snapshot. Listed members follow that order, and missing members follow in stable stored order. The reported example now orders 18, 20, 83, 84 and selects PR 84, instead of 83, 84, 18, 20 and PR 20.

Refs #20370. This is a focused selection fix: it does not refresh sibling snapshots or infer an unavailable host reorder. When every snapshot is stale, the best available snapshot can still be stale.

Verification on 4eaabc4f3e:

• Reduced 6 added cases to 2 in the existing resolver suite: reported ordering/current-PR regression and stable partial-snapshot fallback. Resolver file: 47 → 43 tests; plus 2 existing list-line tests, 45 pass. Both regressions fail against main.
• One independent full-diff review round with Claude Opus 5.5 and Codex GPT-6 Sol: no defects; reviewers independently passed the resolver and focused suites.
• Shared typecheck, targeted lint/format, and diff checks pass. Existing coverage retains derived-chain, host/repository scoping, input immutability, and compatibility without ES2023 array methods.
• Drove the isolated web app with the same synthetic saved snapshots on actual main and head. Current row changes from PR 20 to PR 84; expanded remaining rows change from 83, 84, 18 to 18, 20, 83 (the app displays current first). No backend sync was inferred from the direct visual fixture.
• Shared callers include web, desktop, mobile, and MCP. Native macOS, Windows, iOS, Android, Electron desktop, and live GitHub stack sync were not verified.

Before: main selects PR 20	After: this head selects PR 84

Credit to @ScottN-PV for the original fix in #20388. The takeover preserves the contributor commits and production implementation after independent reassessment, merges current main, and removes redundant test cases.

Implementation: Codex GPT-6.1 Sol; tests: Codex GPT-6 Astra; independent reviews: Claude Opus 5.5 and Codex GPT-6 Sol, through T3 Code.

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Reviewing files that changed from the base of the PR and between dcf8bf4 and e6b85fc.

📒 Files selected for processing: 2

• packages/shared/src/threadPullRequests.test.ts
• packages/shared/src/threadPullRequests.ts

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• packages/shared/src/threadPullRequests.test.ts
• packages/shared/src/threadPullRequests.ts

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📝 Walkthrough

Native pull-request stack reconstruction now selects the saved layer snapshot that covers the most observed members, using the longer snapshot to break coverage ties. Members absent from that snapshot sort after listed members. Tests cover overlapping and partial snapshots, chain and depth order, current top, and input link order.

Changes: Native stack ordering

Layer / File(s)	Summary
Select and apply saved layer order packages/shared/src/threadPullRequests.ts, packages/shared/src/threadPullRequests.test.ts	Ordering selects the candidate saved layer list with the greatest member coverage, preferring the longer list on ties. Members absent from the selected list sort after listed members. Tests check resolved ordering, chain and depth, current top, and preservation of input link order.

Priority: ⬇️ Low

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

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to dcf8b

No merge-blocking issue is identified; the change is ready for normal merge checks.

### Architecture Summary

Architecture risk: 🔵 Low · up to dcf8b

The change affects 1 system.

Changed systems: packages/shared

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — packages/shared (library) was modified; 2 changed files map to changed impact.

Before / after behavior

• observed — Modified behavior in packages/shared/src/threadPullRequests.test.ts: Adds cases with two stored-link orders and overlapping native snapshots. The tests expect the chain to include only linked layers [18, 20, 83, 84] in that order, with depths [0, 1, 2, 3]; the current stack’s top is 84, its open links are ordered [84, 83, 20, 18], and the input link order remains unchanged.
• observed — Modified behavior in packages/shared/src/threadPullRequests.test.ts: Adds cases for partial native snapshots with conflicting or incomplete layer orders. The tests specify the expected resolved layer order for each snapshot set.
• observed — Modified behavior in packages/shared/src/threadPullRequests.ts: Native stack ordering now chooses the candidate saved layers that covers the most observed member numbers, preferring the longer candidate when coverage ties. Members are then sorted by that list’s order, with unlisted members assigned an order after its listed layers. Previously, only the first member’s saved layers determined ordering, and unlisted members sorted at the beginning.

Pre-merge checks: 4

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title is concise, specific, and accurately describes the native stack ordering fix for stale saved layer lists.
Description check		The description provides the problem, implementation details, linked issue, scope limits, focused verification results, screenshots, unverified environments, and agent attribution. It does not use the…

Full details: Description check

Explanation

The description provides the problem, implementation details, linked issue, scope limits, focused verification results, screenshots, unverified environments, and agent attribution. It does not use the template section headings and does not include an explicit maintainer approval comment or explain why approval was unnecessary, but the required information is otherwise substantially complete.

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[juliusmarminge]

Taking over this one as maintainer for batch pull-request-06. I will keep the focused native-stack snapshot fix, reduce the tests to the needed regressions, and verify the ordering and current-PR behavior against main.