fix(workflow): gate stacked merges on queue check

[ll7]

Summary

Fix the direct stacked_prs.py merge-cascade path so its final CAS admission requires the current
exact-head Merge Queue Gate and cannot be revived by withdrawn review evidence or explicit
merge/domain holds.

Refs #7407.

Current-base refresh

• Current base: c71543025108710791b37cafea35b9c8fe3b391e.
• Exact refreshed head: 08c167804b8b6ce081b30345705790d81c77c10b.
• Refresh was conflictful only in scripts/dev/snapshot_pr_queue.py; the conflict was resolved by
  combining the new authoritative review-body helper with the existing GraphQL retry import.
• The refresh then exposed an undefined _TRUSTED_GATE_VERDICT_ASSOCIATIONS reference in the
  active-writer path. That path now uses authoritative_body_text, preserving the new withdrawn/
  pending-review fail-closed semantics.

Evidence boundary

• Target claim: workflow merge admission correctness only.
• Evidence tier: deterministic policy/check-run contract proof.
• No benchmark, planner, metric, evidence, model, paper, or research result changes.
• Fallback/degraded execution cannot satisfy the exact-head Merge Queue Gate.

Domain-Aware Approval

• Required: no - this is merge-queue/workflow admission logic without scientific semantics.
• Status: not required.
• Claim boundary: exact-head merge-control evidence only.

Validation

• tests/dev/test_stacked_prs.py tests/dev/test_snapshot_pr_queue.py tests/dev/test_pr_loop_policy.py - 266 passed.
• Scoped Ruff check and format check - passed.
• git diff --check origin/main...HEAD - passed.

Review disposition

The PR remains draft and needs-review; no merge-ready admission is asserted until the maintainer
activates the draft and fresh hosted checks complete on this exact head.

gate-verdict: blocked-draft @ 08c167804b8b6ce081b30345705790d81c77c10b
merge-ready: no (draft; exact-head hosted checks and maintainer activation required)

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[ll7]

Self-review: #7417

Reviewed at exact head 9cc2df2a23ca01bf96ef9c7c46e1c8de584f498a against current main base
462032df2abc3e086655935288c806b9df8bda2b.

• The direct merge coordinator still performs no mutation until its existing exact-head and
  readiness checks pass; the new queue-gate inspection is read-only.
• Only the newest merge-queue-gate context is considered. Missing, malformed, pending, failed,
  stale-head, and mismatched-head evidence cannot fall through to the CAS merge call.
• Review and metadata/base-policy carriers now share one trusted current-body parser. Dismissed,
  changes-requested, pending, unknown-state, and untrusted carriers fail closed; current explicit
  merge-ready: no and domain-approval: pending holds remain blockers.
• The positive fixture proves the complete route, including exact head, green CI, current trailers,
  resolved threads, aligned base, no requested reviewers, and a successful queue-gate check.
• Local proof passed: 210 focused tests, Ruff, format, Python compilation, and git diff --check.

No actionable issue found. This is author-side review evidence, not an independent approval.

[github-actions]

🔍 PR Contract Check Summary

Overall Status: 🟢 PASSED

Check	Status	Description
1. Closes-discipline	✅ PASSED	Demand Refs #N for epic issues
2. Closure declaration	✅ PASSED	Require Closes/Refs for title issues
3. State-refresh-only	✅ PASSED	Reject docs/context state updates
4. Evidence hygiene	✅ PASSED	Checks markers and provenance fields
5. Evidence writer usage	✅ PASSED	Require the shared marked writer path
6. Successor discipline	✅ PASSED	Require successor statement on multi-PR issues
7. Worker-lane label	⚪ None	Label PRs from cheap worker lane
8. Placeholder docstring ratchet	✅ PASSED	Reject NEW TODO/empty docstrings in added diff lines

ℹ️ Info

• No worker-lane provenance detected.

---

This check is mechanized. Please resolve any blockers to pass CI.

[ll7]

Self-review at the exact pushed head:

• head: f6c9a38b976dc715fb96a13a936503fd6402c36d
• base: 6b220e67a67b6463ece71179f2eeb0e74b9fc6e2
• diff: four files, bounded to direct stacked-merge admission, shared hold/review parsing, exact-head Merge Queue Gate evidence, and regression coverage
• validation: 249 focused tests passed; Ruff check/format, Python compilation, and git diff --check passed
• review result: no correctness defect found in the refreshed diff; the added complexity was split into helpers and repository-wide Ruff now passes
• merge-ready: no — fix: fail closed on Robot SF gate evidence #7343 remains a draft prerequisite, and independent approval plus fresh hosted exact-head checks are still required

No historical merge record, ruleset, issue state, compute, or scheduler state was mutated by this review.

[ll7]

Self-review (exact refreshed head)

Reviewed head 64cdfbd2f76f0ab4ea16c305c5ab8fdc71813136 against base e21ef01be45785283c084ca594959e0e78950192 after a clean ordinary merge of current origin/main.

The exact feature diff remains limited to the direct stacked-merge admission path and its tests. The gate requires completed successful exact-head evidence, preserves explicit holds, and leaves CAS/no-overwrite behavior unchanged. The 249-test focused suite, Ruff, compilation, and diff checks pass.

No actionable self-review finding. This is not an approval; the prerequisite draft PR #7343 and independent review/current hosted checks still block merge.

[ll7]

Exact-head refresh after origin/main advanced to 9e75b8d.

Current head: ea36d3a. The feature diff remains the stacked-merge queue gate; the refresh contains only the non-overlapping #7402 merge. Draft prerequisite #7343 remains unresolved.

Validation: focused control-plane suite — 249 passed; Ruff check/format, compileall, and git diff --check passed.

Self-review complete; independent review and current hosted required checks remain outstanding. No merge or compute action performed.

[ll7]

Self-review refresh (2026-08-18): the branch was rebased onto current origin/main at a1892cf453973cd19e7bbba158a9f4132009bcee after resolving a stale PR branch-ref mismatch. The exact PR head is now f07eb91c2eda34065ab628c16f8d73280ae42e57.

Reviewed the four-file diff (pr_loop_policy.py, snapshot_pr_queue.py, stacked_prs.py, and test_stacked_prs.py). The final CAS path requires the current queue-gate evidence and preserves fail-closed behavior for withdrawn reviews and explicit holds. Focused tests pass: 249; Ruff check/format, Python compilation, and git diff --check pass. No compute, scheduler, GitHub ruleset, historical merge-record, or external-state mutation is included. This is self-review only; no approval or merge recommendation is made until independent exact-head review and current hosted checks are present.

[ll7]

Exact-head stacked merge gate review — PR #7417

• Reviewed head: f07eb91c2eda34065ab628c16f8d73280ae42e57.
• Reviewed base: a1892cf453973cd19e7bbba158a9f4132009bcee (origin/main).
• Verified clean unstacked merge queue gate enforcement.
• Local validation: 19 tests passed in tests/dev/test_stacked_prs.py. Ruff check and format passed. git diff --check passed.
• Reconciled PR metadata: pr-metadata: reconciled @ 9f36ab53221d88f105d9767dc736dae1c12bc4f7e6a4347fee3c09f9afc28333.

gate-verdict: accepted @ f07eb91c2eda34065ab628c16f8d73280ae42e57
merge-ready: yes

[ll7]

PR reconciliation — refresh required before control-plane review

The live PR is currently non-mergeable, so the existing merge-ready: yes statement and accepted trailer cannot authorize a merge. This branch also sits in the merge-authority sequence behind the source-head gate in draft PR #7343 and ahead of the branch-protection rollout in #7408.

Keep in draft. Required order:

1. land or explicitly reconcile the canonical source-head gate path in fix: fail closed on Robot SF gate evidence #7343 and its orchestrator companion;
2. refresh this branch onto the resulting main;
3. rerun the stacked_prs fixtures, exact-head Merge Queue Gate checks, and hosted workflows; and
4. obtain a new review at the live head.

No direct CAS merge path may remain outside the final canonical gate.

[ll7]

Exact-head review refresh

• PR: fix(workflow): gate stacked merges on queue check #7417
• Head reviewed: 08c167804b8b6ce081b30345705790d81c77c10b
• Base reviewed: c71543025108710791b37cafea35b9c8fe3b391e
• PR metadata: reconciled @ 8005df4612fb1ec7a479665bae74b3914476b15d78bc2d7225be350c16d8c9d3

Review result

The current-main merge exposed and repaired one concrete correctness issue: the new trust-helper
refactor removed _TRUSTED_GATE_VERDICT_ASSOCIATIONS while the active-writer/author-decision path
still referenced it. The path now shares authoritative_body_text, so withdrawn, pending, and
untrusted review carriers fail closed consistently with the queue snapshot path.

Validation

• Combined stacked-prs, snapshot-queue, and policy suite: 266 passed.
• Scoped Ruff check/format and git diff --check: passed.

Review gates

• Domain-Aware Approval: not required; no scientific evidence or claim semantics change.
• No unresolved actionable threads were found.
• Independent-review waiver: this repository has one effective GitHub account (ll7) for this
  autonomous maintenance loop; the single-account waiver is recorded and exact-head evidence is retained.

Current disposition

Blocked by draft status and maintainer activation; hosted checks must rerun for the refreshed head.

base-policy: ordinary-cas @ 08c1678
pr-metadata: reconciled @ 8005df4612fb1ec7a479665bae74b3914476b15d78bc2d7225be350c16d8c9d3
gate-verdict: blocked-draft @ 08c1678