A deferred walk is one whose note says so: a failed first ask is watched as before (review of #200)

cmd/mesh-controller/release_plan.go

@@ -465,12 +465,16 @@ func startedBeside(ctx context.Context, inv *inventory.Inventory, id string, cre
 	return "", nil
 }
 
+// deferredNote begins the note of a walk deferred behind another.
+const deferredNote = "let go; starts once "
+
 // deferred says a walk has its word and has not started: let go while another walk was started, it waits for
-// that one to end (startedBeside). Read as a wait, not as a tier running late: `plans` and `status` say its
-// note, and S3 leaves it out.
+// that one to end (startedBeside), and its note says so. Read as a wait, not as a tier running late: `plans`
+// and `status` say its note, and S3 leaves it out. A let-go walk whose first ask failed carries that error as
+// its note instead, and is watched as before.
 func deferred(p inventory.Plan) bool {
 	return p.Open() && p.Release == nil && p.Tier == 0 && !askedAny(p) && p.Delivery != nil &&
-		p.Delivery.Awaits != "" && p.Delivery.Go != nil
+		p.Delivery.Awaits != "" && p.Delivery.Go != nil && strings.HasPrefix(p.Note, deferredNote)
 }
 
 // askedAny says a plan asked any module.
@@ -621,7 +625,7 @@ func advanceOnce(ctx context.Context, open *stores, p *inventory.Plan,
 			if behind, err := startedBeside(ctx, inv, p.ID, p.Created); err != nil {
 				return false, err
 			} else if behind != "" {
-				note := fmt.Sprintf("let go; starts once %s ended — one walk at a time", behind)
+				note := fmt.Sprintf("%s%s ended — one walk at a time", deferredNote, behind)
 				changed := p.Note != note
 				p.Note = note
 				return changed, nil