A routed name resolves to the node whose proxy serves it, never to a provider merely told it (hq 178)

The names region attributed a composed name to whichever labelled contribution a map yielded last.
A dashboard contributes its label to its route and to the identity provider, which must know the
public name for a redirect; so on one plan grafana.<domain> pointed at the proxy's machine and on
the next at the identity provider's, and the whole region flipped with it (forge issue 227). And a
module routed several times contributed no name at all, because the single-value reading of its
contributions is empty for the many shape.

Now every node's resolution is read first and the names are attributed across them at once: the
terminus serves the name — the provider that is not itself published under a labelled name through
another — walked in order, so one mesh yields one region. Name-agnostic, structural, deterministic.

cmd/mesh-controller/plan.go

@@ -731,9 +731,13 @@ func routeNamesInTheMesh(ctx context.Context, open *stores) (map[string]string,
 		return nil, fmt.Errorf("which machines the mesh has cannot be read: %w", err)
 	}
 
-	out := map[string]string{}
+	// Every machine's resolution first, then the names across them at once: which node serves a
+	// name is a question about the graph — the consumer on one machine, the provider on another —
+	// and answered wrongly by looking at one contribution at a time (novox/hq issue 178).
+	plans := map[string]catalogue.Resolution{}
+	settings := map[string]catalogue.SettingsBy{}
 	for _, n := range nodes {
-		plan, settings, err := planFor(ctx, open, n.Name)
+		plan, layers, err := planFor(ctx, open, n.Name)
 		switch {
 		case unresolvable(err):
 			// Their set does not compose, so they serve no names. Passed over, so one machine's
@@ -745,38 +749,16 @@ func routeNamesInTheMesh(ctx context.Context, open *stores) (map[string]string,
 			// operator having withdrawn them (novox/hq 04-ISSUES/152).
 			return nil, fmt.Errorf("the names %s serves cannot be read: %w", n.Name, err)
 		}
-		for _, m := range plan.Modules {
-			for to := range m.Contributes {
-				values, asks, err := plan.ContributionsFrom(to, m.Module, settings)
-				if err != nil {
-					return nil, err
-				}
-				if !asks {
-					continue
-				}
-				// A routed name, and only that: a contribution the mesh composed a name for from a
-				// label it was given. A grant that happens to carry a `name` of its own — a database
-				// name — carries no label and is left alone.
-				if _, labelled := values["label"]; !labelled {
-					continue
-				}
-				name, _ := values["name"].(string)
-				if name == "" {
-					continue
-				}
-				// The node that serves it: whoever answers this consumer's route requirement, or
-				// this same node when the proxy is beside the consumer.
-				serving := n.Name
-				for _, need := range plan.Needs {
-					if need.Name == to && need.For == m.Module {
-						serving = need.From
-						break
-					}
-				}
-				if at := address[serving]; at != "" {
-					out[strings.ToLower(name)] = at
-				}
-			}
+		plans[n.Name], settings[n.Name] = plan, layers
+	}
+	served, err := catalogue.NamesServed(plans, settings)
+	if err != nil {
+		return nil, err
+	}
+	out := map[string]string{}
+	for name, node := range served {
+		if at := address[node]; at != "" {
+			out[name] = at
 		}
 	}
 	return out, nil