internal/composer/composer.go

@@ -134,6 +134,16 @@ func runCase(r Request, c Case, depth string) (CaseVerdict, error) {
 	if err != nil {
 		return CaseVerdict{}, fmt.Errorf("composer: the case %q: %w", c.Name, err)
 	}
+	// The module the mesh provides itself (the private network) has no repository the indexer reads, so no case carries
+	// it: its manifest comes with mesh-sdk and always wins, as the bus reader has it (frombus readBase). Without it a node
+	// it is assigned to composed nothing (issue 1126, check of mesh-host #200: "nothing provides mesh-wireguard").
+	for _, name := range delivery.ProvidedModules() {
+		m, _, err := delivery.ProvidedManifest(name)
+		if err != nil {
+			return CaseVerdict{}, fmt.Errorf("composer: %w", err)
+		}
+		shelf[name] = m
+	}
 	in.Catalogue = shelf
 	in.Nodes = slices.Clone(in.Nodes)
 	in.Holdings = slices.Clone(in.Holdings)

internal/composer/composer_test.go

@@ -60,6 +60,16 @@ func TestARequestItCannotRunIsRefused(t *testing.T) {
 	if _, err := Run(placed); err == nil || !strings.Contains(err.Error(), "holds no node for") {
 		t.Errorf("a case placing a node the input lacks: %v", err)
 	}
+	// Issue 1126 (check of mesh-host #200): the module the mesh provides itself (the private network) comes from mesh-sdk,
+	// a second source beside the indexer's manifests the cases carry, and the input carries no catalogue: a node it is
+	// assigned to still composes, and what it provides is provided.
+	wg := delivery.ProvidedModules()[0]
+	provided := withInput(t, Request{V: Version, Machines: []string{"a"}, Depth: DepthResolve,
+		Cases: []Case{{Name: "change", Manifests: map[string]Manifest{"demo": {Raw: json.RawMessage(demo)}}}}},
+		compose.Input{Nodes: []compose.Node{{Name: "a", Assigned: []string{wg, "demo"}}}})
+	if v, err := Run(provided); err != nil || !v.Cases[0].Machines["a"].Composes {
+		t.Errorf("a node assigned the mesh's own module: %+v, %v", v, err)
+	}
 	v, err := Run(Request{V: Version, Cases: []Case{{Name: "only-read", Manifests: map[string]Manifest{"demo": {Raw: json.RawMessage(demo)}}}}})
 	if err != nil || len(v.Cases) != 1 || !v.Cases[0].Manifests["demo"].Accepted || v.Cases[0].Machines != nil || v.SDK == "" {
 		t.Fatalf("a request with no machines: %+v, %v", v, err)