auto-merge 대기 PR의 update-branch 처리 보강

docs/org-required-workflow-rollout.md

@@ -54,7 +54,7 @@ The central `.github/workflows/pr-review-merge-scheduler.yml` is now part of the
 - PR-event scope: when GitHub invokes the workflow for a PR, the scheduler passes `--pr-number` and inspects only that PR instead of scanning or mutating the whole repository queue
 - Token posture: the workflow passes `GH_TOKEN: ${{ github.token }}` so stale-thread resolution, branch update, auto-merge, and direct merge mutations are attributed to the target repository's `github-actions[bot]`
 - Flow posture: default branches named `main` or `master` are treated as GitHub Flow; default branches named `develop` are treated as Git Flow unless a repository explicitly sets `PROJECT_FLOW`
-- Automation boundary: `update-branch` handles `BEHIND` PRs only after current-head OpenCode approval; `DIRTY` or `CONFLICTING` PRs still require author or maintainer conflict resolution guidance
+- Automation boundary: `update-branch` handles `BEHIND` PRs after current-head OpenCode approval, and also handles PRs where auto-merge is already enabled but compare evidence shows the base branch is ahead; `DIRTY` or `CONFLICTING` PRs still require author or maintainer conflict resolution guidance
 - Retry posture: before retrying OpenCode, the scheduler force-cancels older active OpenCode runs for the same PR number and a previous head SHA. It does not automatically cancel Strix runs because security evidence should not be silently discarded by force-push churn.
 
 Do not centralize the scheduler by running a `.github` scheduled job against other repositories with the `.github` repository token. That would either fail permission checks or use the wrong mutation actor. The central path is a required workflow executed in each target repository context.

scripts/ci/pr_review_merge_scheduler.py

@@ -1077,21 +1077,31 @@ def decide(action: str, reason: str) -> Decision:
         return decide("block", "current-head OpenCode review requested changes")
 
     current_head_approved = has_current_head_approval(pr)
+    auto_merge_enabled = bool(pr.get("autoMergeRequest"))
     behind_by = branch_outdated_by_base(pr, merge_state)
-    if behind_by and current_head_approved:
+    if behind_by and (current_head_approved or auto_merge_enabled):
         if not update_branches:
-            return decide("wait", "current-head OpenCode review approved; branch update disabled")
+            if current_head_approved:
+                return decide("wait", "current-head OpenCode review approved; branch update disabled")
+            return decide("wait", "auto-merge already enabled; branch update disabled")
         if not can_update_pr_head(repo, pr):
             return decide("wait", non_mutable_head_reason(repo, pr))
         update_branch(repo, pr, dry_run=dry_run)
-        suffix = "; existing auto-merge request remains queued" if pr.get("autoMergeRequest") else ""
-        if merge_state == "BEHIND":
+        suffix = "; existing auto-merge request remains queued" if auto_merge_enabled else ""
+        if current_head_approved and merge_state == "BEHIND":
             freshness_reason = "current-head OpenCode review approved"
-        else:
+        elif current_head_approved:
             freshness_reason = (
                 "current-head OpenCode review approved; "
                 f"base branch is {behind_by} commit(s) ahead even though GitHub mergeability is {merge_state}"
             )
+        elif merge_state == "BEHIND":
+            freshness_reason = "auto-merge already enabled"
+        else:
+            freshness_reason = (
+                "auto-merge already enabled; "
+                f"base branch is {behind_by} commit(s) ahead even though GitHub mergeability is {merge_state}"
+            )
         return decide(
             "update_branch",
             f"{freshness_reason}; branch update requested with workflow GH_TOKEN "

tests/test_pr_review_merge_scheduler.py

@@ -1180,6 +1180,41 @@ def test_inspect_pr_blocks_and_waits_for_policy_states(monkeypatch):
     assert "existing auto-merge request remains queued" in blocked_failed_behind_decision.reason
     assert called == [("owner/repo", 1, True)]
     assert disabled == []
+    called.clear()
+    blocked_failed_behind_auto_without_opencode_approval = make_pr(
+        mergeStateStatus="BLOCKED",
+        restMergeableState="BLOCKED",
+        compareBehindBy=2,
+        autoMergeRequest={"enabledAt": "now"},
+        statusCheckRollup={
+            "contexts": {
+                "nodes": [{"__typename": "CheckRun", "name": "strix", "conclusion": "FAILURE"}],
+            }
+        },
+    )
+    blocked_without_opencode_decision = inspect(blocked_failed_behind_auto_without_opencode_approval)
+    assert blocked_without_opencode_decision.action == "update_branch"
+    assert "auto-merge already enabled" in blocked_without_opencode_decision.reason
+    assert "base branch is 2 commit(s) ahead" in blocked_without_opencode_decision.reason
+    assert "existing auto-merge request remains queued" in blocked_without_opencode_decision.reason
+    assert called == [("owner/repo", 1, True)]
+    called.clear()
+    disabled.clear()
+    assert (
+        inspect(blocked_failed_behind_auto_without_opencode_approval, update_branches=False).reason
+        == "auto-merge already enabled; branch update disabled"
+    )
+    assert called == []
+    assert disabled == []
+    behind_auto_without_opencode_approval = make_pr(
+        mergeStateStatus="BEHIND",
+        autoMergeRequest={"enabledAt": "now"},
+    )
+    behind_without_opencode_decision = inspect(behind_auto_without_opencode_approval)
+    assert behind_without_opencode_decision.action == "update_branch"
+    assert behind_without_opencode_decision.reason.startswith("auto-merge already enabled; branch update requested")
+    assert "existing auto-merge request remains queued" in behind_without_opencode_decision.reason
+    assert called == [("owner/repo", 1, True)]
 
 
 def test_inspect_pr_handles_approved_reviews_and_dispatch(monkeypatch):