A first merge into a new repository waits kept for mesh-delivery's word, and the word's arrival asks the builds, with no timer; AC7 on the bus in both orders (issue 1146)

cmd/mesh-controller/moved.go

@@ -115,6 +115,9 @@ func movedOnApprove(d deliveryMerge, ask *asks.Ask, w *asks.Warrant) (string, er
 // keepingDeliveryMerges keeps each merge mesh-delivery announces in the controller's bucket for them.
 type keepingDeliveryMerges struct {
 	js func() *broker.JetStream
+	// kept, when set, is told each merge once it is kept: a first merge waiting for the word asks its builds then
+	// (novox/hq ADR 0432, issue 1146).
+	kept func(ctx context.Context, d deliveryMerge) error
 }
 
 func (k keepingDeliveryMerges) KeepDeliveryMerge(ctx context.Context, body []byte) error {
@@ -137,6 +140,9 @@ func (k keepingDeliveryMerges) KeepDeliveryMerge(ctx context.Context, body []byt
 	if _, err := kv.Put(ctx, deliveryMergeKey(d.Owner, d.Repo, d.Number, d.HeadSHA), body); err != nil {
 		return fmt.Errorf("%w: %w", link.ErrTryAgain, err)
 	}
+	if k.kept != nil {
+		return k.kept(ctx, d)
+	}
 	return nil
 }
 
@@ -239,6 +245,10 @@ func approvedMove(ctx context.Context, inv registrations, forms *sourceForms, bu
 	return approvedAnnounced(ctx, inv, owner, name, announcedOf(merged))
 }
 
+// errWordNotAnApprove says the merge cannot be shown to be the operator's Approve of its head: its announcement names no
+// pull request, or the word on record is not that Approve.
+var errWordNotAnApprove = errors.New("the word on record is no Approve of the head merged")
+
 // errNotAnnounced says mesh-delivery's word on a merge is not kept (yet): the merge may have been made by someone else,
 // or its word may still be on its way.
 var errNotAnnounced = errors.New("mesh-delivery announced no such merge")
@@ -248,7 +258,7 @@ var errNotAnnounced = errors.New("mesh-delivery announced no such merge")
 // module and the first build of a new repository's modules (ADR 0420 §7, ADR 0432).
 func approvedAnnounced(ctx context.Context, inv catalogueReader, owner, name string, k keptMerge) (string, error) {
 	if k.Number <= 0 || k.HeadSHA == "" {
-		return "", errors.New("the forge's announcement of the merge names no pull request or head")
+		return "", fmt.Errorf("%w: the forge's announcement of the merge names no pull request or head", errWordNotAnApprove)
 	}
 	d, kept, err := keptDeliveryMerge(ctx, owner, name, k.Number, k.HeadSHA)
 	if err != nil {
@@ -263,7 +273,7 @@ func approvedAnnounced(ctx context.Context, inv catalogueReader, owner, name str
 	}
 	why, err := movedOnApprove(d, ask, w)
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("%w: %w", errWordNotAnApprove, err)
 	}
 	return fmt.Sprintf("%s/%s#%d merged at %.8s on %s", owner, name, k.Number, k.HeadSHA, why), nil
 }