Announce a plan from a copy that shares nothing with the walk, which goes on writing its steps (issue 1260)

cmd/mesh-controller/delivery.go

@@ -1220,8 +1220,32 @@ func shelfOf(entries []inventory.Entry) map[string]catalogue.Manifest {
 // On the save that starts the walk and the one that ends it, the walk also says what it touches, its bound and,
 // at the end, its outcome (novox/hq ADR 0308 decision 1, walk_said.go), read from facts; nil facts say only what
 // the walk recorded.
+//
+// The plan the announcement is made from is a copy that shares nothing with the walk, taken before the goroutine
+// starts: the walk goes on writing its steps' maps and pointers while the announcement is marshalled and its
+// touches read (novox/hq issue 1260), and it says the plan as it was when this was called.
 func sayPlanMoved(ctx context.Context, bus link.Bus, facts walkFacts, p inventory.Plan) {
-	go publishPlanMoved(ctx, bus, facts, p)
+	kept, err := copyOfPlan(p)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: kept, and could not be said as plan-moved: %v\n", p.ID, err)
+		return
+	}
+	go publishPlanMoved(ctx, bus, facts, kept)
+}
+
+// copyOfPlan is the plan with nothing shared with the original: its JSON round trip, which is all of it but what
+// the plan never keeps (WalkSaid), carried over.
+func copyOfPlan(p inventory.Plan) (inventory.Plan, error) {
+	raw, err := json.Marshal(p)
+	if err != nil {
+		return inventory.Plan{}, err
+	}
+	var kept inventory.Plan
+	if err := json.Unmarshal(raw, &kept); err != nil {
+		return inventory.Plan{}, err
+	}
+	kept.WalkSaid = p.WalkSaid
+	return kept, nil
 }
 
 func publishPlanMoved(ctx context.Context, bus link.Bus, facts walkFacts, p inventory.Plan) {