feat(pr-sync): native assess and author update-by-merge lifecycle

Prevent approved PRs from stalling when master advances. Add gitea_assess_pr_sync_status and gitea_update_pr_branch_by_merge with head/base pinning, author-only updates, conflict handoff, and approval invalidation after head changes. Wire task capability map, sequential controller routing in review-merge workflow, and hermetic AC tests.
2026-07-17 10:42:53 -04:00
parent f65069d22d
commit 98fbfb3de7
6 changed files with 1679 additions and 6 deletions
@@ -950,9 +950,53 @@ Final reports must state:
 * final live head SHA before merge
 * whether any push occurred during validation

+## 26D. PR synchronization and conflict-remediation lifecycle
+
+**Do not treat “approved” as the final readiness state.** For every approved
+open PR, call `gitea_assess_pr_sync_status` (native MCP only) and route by
+`recommended_next_action`:
+
+| Action | Meaning | Next role / tools |
+|--------|---------|-------------------|
+| `merge_now` | Valid approval at exact current head; conflict-free; update not required; checks ok | Merger: sanctioned merge workflow only — **do not** update the branch |
+| `update_branch_by_merge` | Behind live base; protection requires current base; Gitea can merge base without conflicts | **Author only:** `gitea_update_pr_branch_by_merge` with pinned `expected_pr_head_sha` + `expected_base_head_sha` |
+| `author_conflict_remediation` | Conflicts / not auto-updatable | **Author only:** existing `branches/` worktree, issue lock, merge master, resolve, test, push; never force-push/rebase |
+| `fresh_review_required` | Head changed after approval, or update/remediation produced a new head | Independent reviewer at the **new exact head**; old approvals/leases/verdicts are void |
+| `blocked` | Other gate (checks, incomplete facts, closed PR, …) | Diagnose; do not merge or update |
+
+### Hard rules
+
+* Pin both expected PR head and expected base head for every update. Either
+  race → fail closed with no partial mutation.
+* Never rebase or force-push author branches.
+* Never update an author branch from a reviewer or merger profile.
+* Never preserve approval, reviewer lease, merger lease, or prepared verdict
+  across a head change.
+* Process PRs **sequentially**: synchronize/remediate one → review new head →
+  merge → refresh live `master` → reassess the next PR. Do not update every
+  open PR at once (each merge restales the rest).
+* Conflict remediation only in the existing dedicated issue/PR worktree under
+  `branches/`. Do not delete that worktree until the updated PR is merged and
+  cleanup eligibility is proven.
+* Post-merge: canonical cleanup handoff to reconciler (section 28).
+
+### After `gitea_update_pr_branch_by_merge` succeeds
+
+1. Treat former-head approval as invalidated.
+2. Release/supersede obsolete reviewer and merger leases.
+3. Route `recommended_next_action=fresh_review_required` at the new head.
+4. Independent re-review, then merger lease/adopt + merge at the new head only.
+
+All Gitea reads/mutations use native MCP. Never substitute direct API, curl,
+tea/gh, Web UI mutation by an LLM, database changes, raw Git push, or token
+access.
+
 ## 27. Merge rules

-Before merge, rerun fresh live checks:
+Before merge, call `gitea_assess_pr_sync_status` when the PR is approved/open
+and may be behind base. Only proceed with merge when
+`recommended_next_action` is `merge_now` and approval remains at the current
+head. Then rerun fresh live checks:

 * whoami
 * active profile/runtime