Read what a node runs inside its own composition from its haves, not from what the agent applied, so a restarted agent's first composition keeps the bus (issue 1126, review of the fold round 1)

A fresh agent composes before it has applied anything (Running empty), so
InOwn of Running folded only mesh-wireguard and the switch would drop nats.
The composer now watches the node's haves: a placed module whose have names no
new-form fingerprint is folded; one with a new-form have whose want is removed
is not folded. The shadow uses the same set, over the candidate's placement.

internal/selfcompose/selfcompose_test.go

@@ -112,21 +112,33 @@ func TestTheNodeComposesItsWantsFromTheBus(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	// oldie is placed and no want names it (a module at a build of the old form, nats on novox): the node runs it inside
+	// its own composition, and composes it there again, even before the agent has applied anything (Running empty).
+	oldie := `{"module":"oldie","version":"1","capabilities":["systemd"],"resources":[{"id":"service","type":"service","unit":"oldie.service","state":"running","boot":"enabled"}]}`
+	odigest := delivery.ManifestDigest([]byte(oldie))
+	oman, _ := delivery.EncodeManifest(delivery.Manifest{Module: "oldie", JSON: oldie})
+	okey, _ := delivery.ManifestsKey(odigest)
+	b.kv[delivery.ManifestsBucket+"/"+okey] = oman
+	omod, _ := delivery.EncodeModule(delivery.Module{FP2: delivery.SourcePrefix2 + strings.Repeat("c", 64), Manifest: odigest, Repository: "novox/o", Commit: "c"})
 	place, _ := delivery.EncodePlacement(delivery.Placement{Node: "n1", Decided: delivery.NodeDecided{Hub: true, Address: "10.77.0.1"},
-		Modules: []delivery.PlacedModule{{Module: "lemurs"}}})
+		Modules: []delivery.PlacedModule{{Module: "lemurs"}, {Module: "oldie"}}})
 	have, _ := delivery.EncodeHaveNode(delivery.HaveNode{Record: &delivery.NodeRecord{Node: "n1", TunnelKey: "k", SealingKey: "sk", Capabilities: []string{"systemd"}}})
 	mod, _ := delivery.EncodeModule(delivery.Module{FP2: fp, Manifest: digest, Repository: "novox/x", Commit: "c"})
 	want, _ := delivery.EncodeWant(delivery.Want{FP: fp, Self: true})
 	nodeWant, _ := delivery.EncodeNodeWant(delivery.NodeWant{Self: true})
 	b.put(t, delivery.PlacementBucket, "placement.n1", place)
 	b.put(t, delivery.HaveBucket, "n1.node", have)
+	oldHave, _ := delivery.EncodeHave(delivery.Have{Build: "build-1", Phase: delivery.PhaseRunning, Health: delivery.HealthOK})
+	b.put(t, delivery.HaveBucket, "n1.oldie", oldHave)
 	b.put(t, delivery.ModulesBucket, "lemurs", mod)
+	b.put(t, delivery.ModulesBucket, "oldie", omod)
 	b.put(t, delivery.AssignerWantsBucket, "want.n1.lemurs", want)
 	b.put(t, delivery.AssignerWantsBucket, "want.n1.node", nodeWant)
 	for _, bucket := range []string{delivery.AssignerWantsBucket, delivery.PlacementBucket, delivery.HaveBucket, delivery.ModulesBucket, ResolvedBucket} {
 		b.ch(bucket) <- agent.Update{Caught: true}
 	}
 	got := map[string]bool{}
+	var own delivery.Composed
 	for {
 		u := next(t, out)
 		if u.Caught {
@@ -139,8 +151,18 @@ func TestTheNodeComposesItsWantsFromTheBus(t *testing.T) {
 		if c.Node != "n1" {
 			t.Errorf("%s composed for %q", u.Key, c.Node)
 		}
+		if c.Module == "" {
+			own = c
+		}
 		got[u.Key] = true
 	}
+	var ownText []string
+	for _, r := range own.Resources {
+		ownText = append(ownText, string(r))
+	}
+	if !strings.Contains(strings.Join(ownText, " "), `"id":"oldie.service"`) {
+		t.Errorf("the node's own composition, composed before anything was applied, lacks oldie: %v", ownText)
+	}
 	lemursKey, _ := delivery.ComposedKey("n1", "lemurs", fp)
 	nodeKey, _ := delivery.ComposedNodeKey("n1")
 	if !got[lemursKey] || !got[nodeKey] || len(got) != 2 {
@@ -196,7 +218,7 @@ func TestTheNodeComposesItsWantsFromTheBus(t *testing.T) {
 	b.mu.Unlock()
 	kmod, _ := delivery.EncodeModule(delivery.Module{FP2: fp, Manifest: kdigest, Repository: "novox/k", Commit: "c"})
 	both, _ := delivery.EncodePlacement(delivery.Placement{Node: "n1", Decided: delivery.NodeDecided{Hub: true, Address: "10.77.0.1"},
-		Modules: []delivery.PlacedModule{{Module: "lemurs"}, {Module: "keeper"}}})
+		Modules: []delivery.PlacedModule{{Module: "lemurs"}, {Module: "oldie"}, {Module: "keeper"}}})
 	b.put(t, delivery.ModulesBucket, "keeper", kmod)
 	b.put(t, delivery.PlacementBucket, "placement.n1", both)
 	b.put(t, delivery.AssignerWantsBucket, "want.n1.keeper", want)
@@ -448,13 +470,12 @@ func TestTheNodeComposesItsWantsFromTheBus(t *testing.T) {
 	// Issue 1126, the seed's review: a module n1 runs inside its own composition (nats, at a build of the old form) is
 	// composed there again, not at the trunk's build as one added; lemurs at the build it runs, keeper (added) at the
 	// trunk's.
-	inOwnRunning := []delivery.Composed{{Node: "n1", Resources: []json.RawMessage{json.RawMessage(`{"id":"nats.server","type":"service"}`)}},
-		{Node: "n1", Module: "lemurs", FP: fp}}
+	inOwnRunning := []delivery.Composed{{Node: "n1", Module: "lemurs", FP: fp}}
 	other := "src2:" + strings.Repeat("9", 64)
-	gotFps, gotInOwn := shadowBuilds(inOwnRunning, delivery.Placement{Node: "n1", Modules: []delivery.PlacedModule{{Module: "lemurs"}, {Module: "nats"}, {Module: "keeper"}}},
-		map[string]delivery.Module{"lemurs": {FP2: other}, "nats": {FP2: other}, "keeper": {FP2: other}})
-	if fmt.Sprint(gotFps) != fmt.Sprint(map[string]string{"lemurs": fp, "keeper": other}) || fmt.Sprint(gotInOwn) != "[nats]" {
-		t.Errorf("shadow builds %v, in its own %v; want lemurs at what runs, keeper at the trunk's, nats in its own", gotFps, gotInOwn)
+	gotFps := shadowBuilds(inOwnRunning, delivery.Placement{Node: "n1", Modules: []delivery.PlacedModule{{Module: "lemurs"}, {Module: "nats"}, {Module: "keeper"}}},
+		map[string]delivery.Module{"lemurs": {FP2: other}, "nats": {FP2: other}, "keeper": {FP2: other}}, []string{"nats"})
+	if fmt.Sprint(gotFps) != fmt.Sprint(map[string]string{"lemurs": fp, "keeper": other}) {
+		t.Errorf("shadow builds %v; want lemurs at what runs, keeper at the trunk's, nats at none (folded)", gotFps)
 	}
 }