Review of issue 977: keep the plan's own order for its gates, hold a group only for a composed mesh-delivery, keep mark-ready one release, compare with the batch's start, fail a lone cycle (issue 977)

cmd/mesh-controller/checks.go

@@ -154,6 +154,19 @@ func (f following) PullUpdated(ctx context.Context, p link.PullUpdated) error {
 		return err
 	}
 	scope := pullScope(p, entries, read, edges)
+	// **A cycle of edges fails the check, naming every module and edge** (novox/hq ADR 0419 clause 6), a lone pull
+	// request's as a group's composed check is: no order exists for what it changes.
+	alone := orderMember{ID: p.Owner + "/" + p.Repo + "@" + twelve(p.Commit), Repository: p.Owner + "/" + p.Repo, Base: p.Base,
+		Head: p.Commit, Number: p.Number, Paths: p.Paths, PathsTruncated: p.PathsTruncated, Removed: p.Removed, BaseSHA: p.BaseSHA}
+	if failing, cyclic, err := cycleVerdict(ctx, "", []orderMember{alone},
+		map[string]orderReach{alone.ID: {Moved: scope.Modules}}, edges, entries); err != nil {
+		return err
+	} else if cyclic {
+		failing.Commit, failing.Trunk = p.Commit, twelve(p.BaseSHA)
+		fmt.Printf("%s/%s#%d (%.8s): %s\n", p.Owner, p.Repo, p.Number, p.Commit, failing.Summary)
+		sayChecked(ctx, failing)
+		return nil
+	}
 	// **A member of a group whose gate is the composed check's runs its repository's check alone** (novox/hq ADR 0403
 	// clause 1): mesh-delivery is asked once, and says so on the group's line. Told nothing, the pull request is
 	// checked alone, gate included (clause 6).