mesh-sdk/go/compose/frombus/frombus_test.go

package frombus

import (
	"archive/tar"
	"bytes"
	"compress/gzip"
	"context"
	"crypto/ecdh"
	"crypto/rand"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"reflect"
	"slices"
	"strings"
	"testing"

	"git.novox.be/novox/mesh-sdk/go/catalogue"
	"git.novox.be/novox/mesh-sdk/go/compose"
	"git.novox.be/novox/mesh-sdk/go/delivery"
	"git.novox.be/novox/mesh-sdk/go/overlay"
)

// bus is a Reader over values held in memory, counting whose config values were read.
type bus struct {
	placements map[string]delivery.Placement
	records    map[string]delivery.NodeRecord
	modules    map[string]delivery.Module
	manifests  map[string][]byte
	values     map[string]map[string]any // by node.module
	valuesRead []string
	own        []compose.OwnSecretRow
	ownErr     error
	// asked is every consumer credential asked; the fake refuses the whole ask, as the vault's own does, for a consuming
	// module its placement does not put on the node.
	asked []compose.CredentialKey
	// builds are the builder's keys, by "<module> <fp>"; archives the artifact store's blobs, by digest, and fetched
	// every URL asked; served another node's values by "<node>.<module>", and servedRead every ask with its keys.
	builds     map[string]*delivery.BuilderBuild
	archives   map[string][]byte
	fetched    []string
	served     map[string]map[string]any
	servedRead []string
}

func (b *bus) Build(_ context.Context, module, fp string) (*delivery.BuilderBuild, error) {
	return b.builds[module+" "+fp], nil
}

func (b *bus) Archive(_ context.Context, url, digest string) ([]byte, error) {
	b.fetched = append(b.fetched, url)
	body, ok := b.archives[digest]
	if !ok {
		return nil, errors.New("the store holds no such blob")
	}
	return body, nil
}

func (b *bus) Served(_ context.Context, node, module string, keys []string) (map[string]any, error) {
	b.servedRead = append(b.servedRead, node+"."+module+":"+strings.Join(keys, ","))
	out := map[string]any{}
	for _, k := range keys {
		if v, ok := b.served[node+"."+module][k]; ok {
			out[k] = v
		}
	}
	return out, nil
}

func (b *bus) Placements(context.Context) (map[string]delivery.Placement, error) {
	return b.placements, nil
}
func (b *bus) Records(context.Context) (map[string]delivery.NodeRecord, error) { return b.records, nil }
func (b *bus) Modules(context.Context) (map[string]delivery.Module, error)     { return b.modules, nil }
func (b *bus) Manifest(_ context.Context, digest string) ([]byte, error) {
	raw, ok := b.manifests[digest]
	if !ok {
		return nil, errors.New("no such manifest")
	}
	return raw, nil
}
func (b *bus) OwnSecrets(context.Context, string) ([]compose.OwnSecretRow, error) {
	return b.own, b.ownErr
}

func (b *bus) Credentials(_ context.Context, node string, asConsumer, _ []compose.CredentialKey) ([]compose.Credential, []compose.Issued, error) {
	b.asked = append(b.asked, asConsumer...)
	for _, k := range asConsumer {
		placed := false
		for _, m := range b.placements[node].Modules {
			placed = placed || m.Module == k.ConsumerModule
		}
		if !placed {
			return nil, nil, fmt.Errorf("%s is not on %s: neither assigned there nor required by a module there", k.ConsumerModule, node)
		}
	}
	return nil, nil, nil
}

func (b *bus) Values(_ context.Context, node, module string) (map[string]any, error) {
	b.valuesRead = append(b.valuesRead, node+"."+module)
	return b.values[node+"."+module], nil
}

func publicKey(t *testing.T) string {
	t.Helper()
	k, err := ecdh.X25519().GenerateKey(rand.Reader)
	if err != nil {
		t.Fatal(err)
	}
	return base64.StdEncoding.EncodeToString(k.PublicKey().Bytes())
}

// Issue 1126 (S3, S4, S5): the bus's placement, node records, manifests and config values fill the same compose.Input the
// controller's store fills for compose's own two-machine mesh (compose's aMesh: anchor the hub, laptop), and that Input
// composes; a node reads only its own config values; what cannot be composed is refused, naming it.
func TestInput(t *testing.T) {
	ctx := context.Background()
	xterm, err := os.ReadFile("../../catalogue/testdata/catalogue-835bf22b-xterm.module.json")
	if err != nil {
		t.Fatal(err)
	}
	digest := delivery.ManifestDigest(xterm)
	// A module in the settings form (plex and the media modules on one node, 2026-10-26): its config values are in its
	// layers, not mesh-config, so the placement carries them (MeshValues, Values) and mesh-config's are not read for it.
	media := []byte(`{"module":"media","version":"1","settings":{"lines":{"kind":"preference","default":0,"why":"kept"},` +
		`"name":{"kind":"preference","default":"x","why":"shown"}},"own-secrets":{"token":"/srv/media/token"},"resources":[{"id":"conf","type":"file",` +
		`"path":"/srv/media/conf","mode":"0644","content":"uid=${setting:lines} name=${setting:name}\n"}]}`)
	mediaDigest := delivery.ManifestDigest(media)
	keys := map[string]string{"anchor": publicKey(t), "laptop": publicKey(t)}
	caps := []string{"container-runtime", "systemd", "wireguard"}
	tunnel := &delivery.RecordTunnel{Interface: "wg0", PublicKey: keys["anchor"], Address: "10.77.0.1/24",
		Peers: []delivery.RecordTunnelPeer{{PublicKey: "peer", Address: "10.77.0.9/32"}, {PublicKey: keys["laptop"], Address: "10.77.0.2/32"}}}
	mk := func() *bus {
		return &bus{
			placements: map[string]delivery.Placement{
				"anchor": {Node: "anchor", Decided: delivery.NodeDecided{Endpoint: "anchor.example:51820", Site: "here", Hub: true, Address: "10.77.0.1",
					Tunnel: tunnel, PeerNames: map[string]string{"peer": "phone"}},
					Modules: []delivery.PlacedModule{{Module: overlay.Name}},
					Holds:   []delivery.Holding{{Claim: "mesh-private-network", Scope: "mesh", Module: overlay.Name}}},
				"laptop": {Node: "laptop", Decided: delivery.NodeDecided{Endpoint: "laptop.example:51820", Site: "here", Address: "10.77.0.2"},
					Modules: []delivery.PlacedModule{{Module: overlay.Name},
						{Module: "xterm", HasLayer: true, Ports: map[string]int{"80": 8080}},
						{Module: "media", HasMesh: true, MeshValues: map[string]any{"name": "mesh"}, HasLayer: true,
							Layer: map[string]any{"places": map[string]any{"data": "/srv/data"}}, Values: map[string]any{"lines": float64(1000)}}}},
			},
			records: map[string]delivery.NodeRecord{
				"anchor": {Node: "anchor", TunnelKey: keys["anchor"], Capabilities: caps, Contract: 2},
				"laptop": {Node: "laptop", TunnelKey: keys["laptop"], Capabilities: caps, Authority: "the mesh's certificate"},
			},
			modules:   map[string]delivery.Module{"xterm": {Manifest: digest}, "media": {Manifest: mediaDigest}, "unread": {}},
			manifests: map[string][]byte{digest: xterm, mediaDigest: media},
			values: map[string]map[string]any{"laptop.xterm": {"font": "mono"}, "anchor.xterm": {"font": "serif"},
				"laptop.media": {"lines": "not mesh-config's"}},
			own: []compose.OwnSecretRow{{Node: "laptop", Module: "media", Name: "token", Origin: "made", SealedTo: "sk", Sealed: "{}"}},
		}
	}

	// What the controller's store gives for the same mesh, as compose's aMesh and SettingsFor build it.
	var private catalogue.Manifest
	raw, _ := json.Marshal(overlay.Manifest())
	if err := json.Unmarshal(raw, &private); err != nil {
		t.Fatal(err)
	}
	parsed, err := catalogue.ParseManifestForInputs(xterm)
	if err != nil {
		t.Fatal(err)
	}
	parsedMedia, err := catalogue.ParseManifestForInputs(media)
	if err != nil {
		t.Fatal(err)
	}
	capsSet := map[string]bool{"container-runtime": true, "systemd": true, "wireguard": true}
	tun := compose.Tunnel{Interface: "wg0", PublicKey: keys["anchor"], Address: "10.77.0.1/24",
		Peers: []compose.TunnelPeer{{PublicKey: "peer", Address: "10.77.0.9/32"}, {PublicKey: keys["laptop"], Address: "10.77.0.2/32"}}}
	want := compose.Input{
		Catalogue: map[string]catalogue.Manifest{overlay.Name: private, "xterm": parsed, "media": parsedMedia},
		Nodes: []compose.Node{
			{Name: "anchor", Place: compose.Place{Key: keys["anchor"], Endpoint: "anchor.example:51820", Site: "here", Hub: true,
				Address: "10.77.0.1"}, Assigned: []string{overlay.Name}, Capabilities: capsSet, Contract: 2, Stated: true},
			{Name: "laptop", Place: compose.Place{Key: keys["laptop"], Endpoint: "laptop.example:51820", Site: "here",
				Address: "10.77.0.2"}, Assigned: []string{overlay.Name, "xterm", "media"}, Capabilities: capsSet,
				Ports: map[string]map[int]int{"xterm": {80: 8080}},
				Settings: map[string][]catalogue.Layer{"xterm": {{From: "laptop", Values: map[string]any{"font": "mono"}}},
					"media": {{From: catalogue.MeshWideLayer, Values: map[string]any{"name": "mesh"}},
						{From: "laptop", Values: map[string]any{"lines": float64(1000)}, Placement: map[string]any{"places": map[string]any{"data": "/srv/data"}}}}}},
		},
		Holdings:   []catalogue.Held{{Claim: "mesh-private-network", Scope: "mesh", Node: "anchor", Module: overlay.Name}},
		OwnSecrets: []compose.OwnSecretRow{{Node: "laptop", Module: "media", Name: "token", Origin: "made", SealedTo: "sk", Sealed: "{}"}},
		// The same value as a core credential's box, for a core module (ADR 0349 §16).
		KeptCoreBoxes: []compose.CoreBox{{Node: "laptop", Module: "media", Name: "token", SealedTo: "sk", Box: json.RawMessage("{}")}},
		Tunnels:       map[string]compose.FoundTunnel{"anchor": {Tunnel: tun}},
		Adopted:       &compose.AdoptedTunnel{Tunnel: tun, Hub: "anchor", Adopted: true},
		// The controller's order is by address; laptop enrolled under its peer's key, and a person named the other.
		Authority: "the mesh's certificate",
		CarriedPeers: []compose.CarriedPeer{{PublicKey: keys["laptop"], Address: "10.77.0.2", EnrolledAs: "laptop"},
			{PublicKey: "peer", Address: "10.77.0.9", Named: "phone"}},
	}

	b := mk()
	got, err := Input(ctx, b, Mesh{}, Scope{Node: "laptop"})
	if err != nil {
		t.Fatal(err)
	}
	if !reflect.DeepEqual(got, want) {
		gj, _ := json.MarshalIndent(got, "", " ")
		wj, _ := json.MarshalIndent(want, "", " ")
		t.Fatalf("Input from the bus differs from the store's:\n got %s\nwant %s", gj, wj)
	}
	if !reflect.DeepEqual(b.valuesRead, []string{"laptop." + overlay.Name, "laptop.xterm", "laptop.media"}) {
		t.Errorf("laptop read config values %v; a node reads its own slice alone", b.valuesRead)
	}

	// The same composer over both: the compositions from the bus are the store's, byte for byte.
	fps := map[string]string{overlay.Name: "src2:" + strings.Repeat("a", 64), "xterm": "src2:" + strings.Repeat("b", 64),
		"media": "src2:" + strings.Repeat("c", 64)}
	fromBus, _, err := Compose(ctx, mk(), Mesh{}, Scope{Node: "laptop"}, fps)
	if err != nil {
		t.Fatal(err)
	}
	fromStore, _, err := compose.Compositions(want, "laptop", fps, compose.Reading)
	if err != nil {
		t.Fatal(err)
	}
	if len(fromBus) == 0 || !reflect.DeepEqual(fromBus, fromStore) {
		t.Fatalf("compositions differ or are empty: %d from the bus, %d from the store", len(fromBus), len(fromStore))
	}

	// Issue 1126: a candidate placement equal to the node's composes what it runs, and CompareComposed says so; one
	// thing changed in the group's candidate of another node (the hub's endpoint) names exactly the module it moves
	// here. Placed puts the same placement over the store's input unchanged.
	running := make([]delivery.Composed, 0, len(fromBus))
	for _, c := range fromBus {
		running = append(running, c)
	}
	laptop := mk().placements["laptop"]
	asIs, _, err := Compose(ctx, mk(), Mesh{}, Scope{Node: "laptop", Placements: map[string]*delivery.Placement{"laptop": &laptop}}, fps)
	if err != nil {
		t.Fatal(err)
	}
	if c := delivery.CompareComposed(asIs, running); len(c.Differs)+len(c.Added)+len(c.Removed) != 0 || len(c.Same) != len(running) {
		t.Errorf("the candidate equal to the placement: %+v", c)
	}
	moved := mk().placements["anchor"]
	moved.Decided.Endpoint = "anchor.example:51821"
	changed, _, err := Compose(ctx, mk(), Mesh{}, Scope{Node: "laptop", Placements: map[string]*delivery.Placement{"laptop": &laptop, "anchor": &moved}}, fps)
	if err != nil {
		t.Fatal(err)
	}
	if c := delivery.CompareComposed(changed, running); len(c.Differs) != 1 || c.Differs[0].Module != overlay.Name || c.Differs[0].Resource != overlay.Name+".overlay-config" {
		t.Errorf("the hub's endpoint changed: %+v, want %s alone, naming its config", c, overlay.Name)
	}
	if c := delivery.CompareComposed(changed, running[:0]); len(c.Added) != len(changed) {
		t.Errorf("nothing runs: %+v", c)
	}

	// ADR 0559 §4, the node's answer: the same; one module differing; a module the group adds, whose own secret is not
	// yet issued (no refusal); a value missing for a module the node runs (a refusal); a module the candidate removes.
	keeper := []byte(`{"module":"keeper","version":"1","own-secrets":{"password":"/var/lib/mesh/keeper/password"},` +
		`"resources":[{"id":"state","type":"directory","path":"/var/lib/mesh/keeper","mode":"0700"}]}`)
	lemurs := []byte(`{"module":"lemurs","version":"1","capabilities":["systemd"],"resources":[{"id":"service","type":"service","unit":"lemurs.service","state":"running","boot":"enabled"}]}`)
	// A provider and a consumer of a pair credential on the one node (compose's objects and files).
	objects, _ := json.Marshal(catalogue.Manifest{Module: "objects", Version: "1",
		Provides: []catalogue.Offer{{Name: "s3-bucket", Scope: catalogue.ScopeMesh, Identity: &catalogue.OfferIdentity{Max: 20, In: "an S3 access key"}}},
		Receives: map[string]string{"s3-bucket": "/var/lib/mesh/objects/mesh.json"}})
	files, _ := json.Marshal(catalogue.Manifest{Module: "files", Version: "1", Requires: []string{"s3-bucket"},
		Resources: []map[string]any{{"id": "config", "type": "file", "path": "/etc/files/config.json", "mode": "0600", "content": "{}", "merge": "json"}}})
	one := func(placed ...string) *bus {
		p := delivery.Placement{Node: "n1", Decided: delivery.NodeDecided{Hub: true, Address: "10.77.0.1"}}
		for _, m := range placed {
			p.Modules = append(p.Modules, delivery.PlacedModule{Module: m})
		}
		return &bus{placements: map[string]delivery.Placement{"n1": p},
			records: map[string]delivery.NodeRecord{"n1": {Node: "n1", TunnelKey: keys["anchor"], SealingKey: "sk", Capabilities: []string{"systemd"}}},
			modules: map[string]delivery.Module{"keeper": {Manifest: delivery.ManifestDigest(keeper)}, "lemurs": {Manifest: delivery.ManifestDigest(lemurs)},
				"objects": {Manifest: delivery.ManifestDigest(objects)}, "files": {Manifest: delivery.ManifestDigest(files)}},
			manifests: map[string][]byte{delivery.ManifestDigest(keeper): keeper, delivery.ManifestDigest(lemurs): lemurs,
				delivery.ManifestDigest(objects): objects, delivery.ManifestDigest(files): files},
			own: []compose.OwnSecretRow{{Node: "n1", Module: "keeper", Name: "password", Origin: "made", SealedTo: "sk", Sealed: `"box"`}}}
	}
	oneFps := map[string]string{"keeper": "src2:" + strings.Repeat("d", 64), "lemurs": "src2:" + strings.Repeat("e", 64),
		"objects": "src2:" + strings.Repeat("f", 64), "files": "src2:" + strings.Repeat("0", 64)}
	runs, _, err := Compose(ctx, one("keeper", "lemurs"), Mesh{}, Scope{Node: "n1"}, oneFps)
	if err != nil {
		t.Fatal(err)
	}
	var runsNow []delivery.Composed
	for _, c := range runs {
		runsNow = append(runsNow, c)
	}
	objectsRun, _, err := Compose(ctx, one("objects"), Mesh{}, Scope{Node: "n1"}, oneFps)
	if err != nil {
		t.Fatal(err)
	}
	var consumerRuns []delivery.Composed
	for _, c := range objectsRun {
		consumerRuns = append(consumerRuns, c)
	}
	withoutOwn := func(cs []delivery.Composed) []delivery.Composed {
		var out []delivery.Composed
		for _, c := range cs {
			if c.Module != "" {
				out = append(out, c)
			}
		}
		return out
	}
	// What the controller runs on n1 for a module no want names (lemurs, at a build of the old form) and the private
	// network's (built by nobody): its composed writer (mesh-controller compositionsOf) folds their resources into the
	// node's own, each in its place, its module taken off; the rest split by module.
	tunnelled := func() *bus {
		b := one("keeper", "lemurs", overlay.Name)
		p := b.placements["n1"]
		p.Decided.Endpoint = "n1.example:51820"
		b.placements["n1"] = p
		return b
	}
	tunnelledAs := func() map[string]*delivery.Placement {
		p := tunnelled().placements["n1"]
		return map[string]*delivery.Placement{"n1": &p}
	}
	folded := func() []delivery.Composed {
		b := tunnelled()
		in, err := Input(ctx, b, Mesh{}, Scope{Node: "n1"})
		if err != nil {
			t.Fatal(err)
		}
		reading := in
		reading.Nodes = append([]compose.Node(nil), in.Nodes...)
		reading.Nodes[0].ReadsModules = true
		d, _, err := compose.ComposeIn(reading, "n1", compose.Reading)
		if err != nil {
			t.Fatal(err)
		}
		body, err := d.Body()
		if err != nil {
			t.Fatal(err)
		}
		var envelope struct {
			Resources []map[string]json.RawMessage `json:"resources"`
		}
		if err := json.Unmarshal(body, &envelope); err != nil {
			t.Fatal(err)
		}
		var resources []json.RawMessage
		for _, r := range envelope.Resources {
			var module string
			_ = json.Unmarshal(r["module"], &module)
			if module == "lemurs" || module == overlay.Name {
				delete(r, "module")
			}
			raw, _ := json.Marshal(r)
			resources = append(resources, raw)
		}
		split, err := delivery.SplitComposed("n1", resources, map[string]string{"keeper": oneFps["keeper"]}, nil, delivery.NodeOwn{})
		if err != nil {
			t.Fatal(err)
		}
		var out []delivery.Composed
		for _, c := range split {
			out = append(out, c)
		}
		return out
	}()
	if got := InOwn(folded, tunnelled().placements["n1"]); !reflect.DeepEqual(got, []string{"lemurs", overlay.Name}) {
		t.Errorf("InOwn of the controller's composition = %v, want lemurs and %s", got, overlay.Name)
	}
	placedAs := func(modules ...string) map[string]*delivery.Placement {
		p := one(modules...).placements["n1"]
		return map[string]*delivery.Placement{"n1": &p}
	}
	for name, c := range map[string]struct {
		b       *bus
		given   map[string]*delivery.Placement
		running []delivery.Composed
		verdict string
		check   func(delivery.CandidateAnswer) bool
	}{
		"the same": {one("keeper", "lemurs"), placedAs("keeper", "lemurs"), runsNow, delivery.CandidateSame,
			func(a delivery.CandidateAnswer) bool { return len(a.Same) == 3 && a.Head == "h1" && a.Revision == 7 }},
		"the node runs no own composition": {one("keeper", "lemurs"), placedAs("keeper", "lemurs"), withoutOwn(runsNow), delivery.CandidateSame,
			func(a delivery.CandidateAnswer) bool { return len(a.Same) == 2 && len(a.Added) == 0 }},
		"one removed": {one("keeper", "lemurs"), placedAs("keeper"), runsNow, delivery.CandidateDiffers,
			func(a delivery.CandidateAnswer) bool { return reflect.DeepEqual(a.Removed, []string{"lemurs"}) }},
		"one added, its secret not yet issued": {func() *bus { b := one("lemurs"); b.own = nil; return b }(), placedAs("keeper", "lemurs"),
			nil, delivery.CandidateDiffers, func(a delivery.CandidateAnswer) bool {
				for _, m := range a.Added {
					if m.Module == "keeper" {
						return reflect.DeepEqual(m.Unissued, []string{"keeper/password"}) && len(a.Refusals) == 0
					}
				}
				return false
			}},
		"a value missing for a module that runs": {func() *bus { b := one("keeper", "lemurs"); b.own = nil; return b }(), placedAs("keeper", "lemurs"),
			runsNow, delivery.CandidateRefused, func(a delivery.CandidateAnswer) bool {
				return len(a.Refusals) == 1 && a.Refusals[0].Module == "keeper" && strings.Contains(a.Refusals[0].Why, "keeper/password")
			}},
		// Review of L2b, round 1, finding 1: a consumer the candidate adds has no credential yet, and the vault refuses an
		// ask for a module not on the node; it is not asked, and the module is added, its credential not yet issued.
		"a consumer added, the vault not asked for it": {one("objects"), placedAs("objects", "files"), consumerRuns, delivery.CandidateDiffers,
			func(a delivery.CandidateAnswer) bool {
				return len(a.Added) == 1 && a.Added[0].Module == "files" && len(a.Added[0].Unissued) > 0 && len(a.Refusals) == 0
			}},
		// And with no trunk at all (the seed), a stand-in of a module the node runs is a refusal, not an addition.
		"the seed, a value missing for a module that runs": {func() *bus { b := one(); b.own = nil; return b }(), placedAs("keeper", "lemurs"),
			runsNow, delivery.CandidateRefused, func(a delivery.CandidateAnswer) bool {
				return len(a.Refusals) == 1 && a.Refusals[0].Module == "keeper" && len(a.Added) == 0
			}},
		"cannot compose": {one("keeper"), map[string]*delivery.Placement{"n1": {Node: "n2"}}, runsNow, delivery.CandidateRefused,
			func(a delivery.CandidateAnswer) bool { return a.Refused != "" }},
		// Issue 1126 (the seed's review): the private network's module and one at a build of the old form, which no want
		// names and the controller folds into the node's own, are folded there again: the node's own is the same, and
		// neither is added.
		"mesh-wireguard and an old-form module, folded": {tunnelled(), tunnelledAs(),
			folded, delivery.CandidateSame, func(a delivery.CandidateAnswer) bool { return len(a.Same) == 2 && len(a.Added) == 0 }},
	} {
		fps := oneFps
		if name == "mesh-wireguard and an old-form module, folded" {
			fps = map[string]string{"keeper": oneFps["keeper"]} // the node's wants: no build of lemurs or the private network
		}
		a := Answer(ctx, c.b, Mesh{}, Scope{Node: "n1", Placements: c.given, InOwn: InOwn(c.running, *c.given["n1"])}, fps, c.running, "h1", 7)
		if a.Verdict != c.verdict || !c.check(a) {
			t.Errorf("%s: %+v", name, a)
		}
		if raw, err := delivery.EncodeHaveNode(delivery.HaveNode{Candidates: map[string]delivery.CandidateAnswer{"g": a}}); err != nil {
			t.Errorf("%s: the answer is not one a have holds: %v (%s)", name, err, raw)
		}
	}
	if got, err := Placed(want, map[string]*delivery.Placement{"laptop": &laptop}); err != nil || !reflect.DeepEqual(got, want) {
		t.Errorf("Placed with the node's own placement changes the input: %v", err)
	}
	if got, err := Placed(want, map[string]*delivery.Placement{"laptop": nil}); err != nil || len(got.Nodes[1].Assigned) != 0 || got.Nodes[1].Place.Key != keys["laptop"] {
		t.Errorf("Placed with no placement: %+v, %v", got.Nodes[1], err)
	}
	if _, err := Placed(want, map[string]*delivery.Placement{"stranger": {Node: "stranger"}}); err == nil {
		t.Error("Placed a node the input holds no node for")
	}
	if _, err := Input(ctx, mk(), Mesh{}, Scope{Node: "laptop", Placements: map[string]*delivery.Placement{"laptop": {Node: "anchor"}}}); err == nil {
		t.Error("a given placement naming another node was taken")
	}

	// ADR 0555 §6: Export is Input's inverse for what a person decides: the store's input exported, node by node, is the
	// placement the bus holds, and read back it is the store's input again.
	for node, placed := range mk().placements {
		got, err := Export(want, node)
		if err != nil {
			t.Fatal(err)
		}
		if gj, _ := delivery.EncodePlacement(got); !delivery.SamePlacement(got, placed) {
			pj, _ := delivery.EncodePlacement(placed)
			t.Errorf("%s exported as %s, want %s", node, gj, pj)
		}
	}
	if _, err := Export(want, "stranger"); err == nil {
		t.Error("a node the input lacks was exported")
	}

	b = mk()
	if every, err := Input(ctx, b, Mesh{}, Scope{Every: true}); err != nil || every.OwnSecrets != nil {
		t.Fatalf("composing every node: %v, own secrets %v (the vault answers a node about itself alone)", err, every.OwnSecrets)
	}
	if !reflect.DeepEqual(b.valuesRead, []string{"anchor." + overlay.Name, "laptop." + overlay.Name, "laptop.xterm", "laptop.media"}) {
		// Every node's placed modules, and nothing placed nowhere: anchor places no xterm.
		t.Errorf("the check read %v", b.valuesRead)
	}

	// A node none of whose modules declares an own secret composes without asking the vault (the review of L2: a node
	// with no secret composed nothing while the vault did not answer); one whose module does, refuses without it.
	quiet := mk()
	quiet.ownErr = errors.New("no responders")
	if _, err := Input(ctx, quiet, Mesh{}, Scope{Node: "anchor"}); err != nil {
		t.Errorf("anchor, with no own secret, needed the vault: %v", err)
	}
	if _, err := Input(ctx, quiet, Mesh{}, Scope{Node: "laptop"}); err == nil {
		t.Error("laptop's media, which declares an own secret, composed without the vault")
	}

	// A module the node's want keeps at another build than the trunk's composes from that build's manifest, resolved with
	// what it made (issue 1126), on the composing node alone.
	kept := mk()
	oldXterm := []byte(`{"module":"xterm","version":"1","resources":[{"id":"tools","type":"process","name":"xterm-tools",` +
		`"artifact":"tools","run":["./xterm-tools"]}],"build":{"artifacts":[{"name":"tools","kind":"bundle","language":"go","system":"arch","from":"cmd/xterm-tools","binary":"xterm-tools"}]}}`)
	kept.manifests["old"] = oldXterm
	oldFP := "src2:" + strings.Repeat("9", 64)
	toolsRef := "artifact-store://xterm/tools/blobs/sha256:" + strings.Repeat("1", 64)
	kept.builds = map[string]*delivery.BuilderBuild{"xterm " + oldFP: {State: delivery.BuildDone, Manifest: "old",
		Artifacts: []delivery.BuiltArtifact{{Name: "tools", Kind: "bundle", Reference: toolsRef, Digest: "sha256:" + strings.Repeat("1", 64)}}}}
	parsedOld, err := catalogue.ParseManifestForInputs(oldXterm)
	if err != nil {
		t.Fatal(err)
	}
	keptBuilt, err := parsedOld.Resolve([]catalogue.Built{{Name: "tools", Kind: "bundle", Reference: toolsRef, Digest: "sha256:" + strings.Repeat("1", 64)}})
	if err != nil {
		t.Fatal(err)
	}
	in, err := Input(ctx, kept, Mesh{}, Scope{Node: "laptop", KeptAt: map[string]string{"xterm": oldFP}})
	if err != nil || !reflect.DeepEqual(in.Nodes[1].Kept, map[string]catalogue.Manifest{"xterm": keptBuilt}) || in.Nodes[0].Kept != nil {
		t.Errorf("the want's build is kept on the composing node alone: %v, %v", in.Nodes, err)
	}

	// Issue 1126, the seed's refusals. restic and the provisioner's client as the catalogue holds them (mesh-catalog
	// c05aa5e6), restic moved with an own secret the vault leaves out (it hands it to the client, mesh-vault ownnode.go
	// handed): composed from the indexer's manifest restic is not handed and stands in for that secret, as novox's,
	// ace's, g14's and shanks's answers refused; composed from its build, it is handed, its templates archive read
	// where the node reaches the artifact store, and the composition is the one the controller's take-in gives.
	resticRaw, err := os.ReadFile("testdata/catalogue-c05aa5e6-restic.module.json")
	if err != nil {
		t.Fatal(err)
	}
	clientRaw, err := os.ReadFile("testdata/catalogue-c05aa5e6-mesh-provisioner-client.module.json")
	if err != nil {
		t.Fatal(err)
	}
	store := []byte(`{"module":"store","version":"1","provides":[{"name":"artifact-store","scope":"mesh"}],` +
		`"serves":{"artifact-store":{"port":5000}}}`)
	texts := map[string]string{}
	var packed bytes.Buffer
	zw := gzip.NewWriter(&packed)
	tw := tar.NewWriter(zw)
	for _, f := range []string{"backups.conf", "data.conf", "retention.conf"} {
		text, err := os.ReadFile("testdata/catalogue-c05aa5e6-restic.files/" + f)
		if err != nil {
			t.Fatal(err)
		}
		texts[f] = string(text)
		if err := tw.WriteHeader(&tar.Header{Name: "./" + f, Mode: 0o644, Size: int64(len(text)), Typeflag: tar.TypeReg}); err != nil {
			t.Fatal(err)
		}
		if _, err := tw.Write(text); err != nil {
			t.Fatal(err)
		}
	}
	if err := tw.Close(); err != nil {
		t.Fatal(err)
	}
	if err := zw.Close(); err != nil {
		t.Fatal(err)
	}
	archiveDigest := delivery.ManifestDigest(packed.Bytes())
	digestOf := func(c string) string { return "sha256:" + strings.Repeat(c, 64) }
	movedFps := map[string]string{"restic": "src2:" + strings.Repeat("3", 64), "mesh-provisioner-client": "src2:" + strings.Repeat("4", 64),
		"store": "src2:" + strings.Repeat("5", 64)}
	resticArtifacts := []delivery.BuiltArtifact{{Name: "tools", Kind: "bundle", Reference: "artifact-store://restic/tools/blobs/" + digestOf("6"), Digest: digestOf("6")},
		{Name: "files", Kind: "archive", Reference: "artifact-store://restic/files/blobs/" + archiveDigest, Digest: archiveDigest}}
	clientArtifacts := []delivery.BuiltArtifact{{Name: "client", Kind: "bundle", Reference: "artifact-store://mesh-provisioner-client/client/blobs/" + digestOf("7"), Digest: digestOf("7")}}
	movedMesh := func(built bool) *bus {
		b := one()
		p := b.placements["n1"]
		p.Modules = []delivery.PlacedModule{{Module: "store"}, {Module: "mesh-provisioner-client"}, {Module: "restic"}}
		p.Decided.Account, p.Decided.AccountHome = "operator", "/home/operator"
		b.placements["n1"] = p
		rec := b.records["n1"]
		rec.Contract, rec.Capabilities = compose.HandedContract, []string{"systemd", "package-manager"}
		b.records["n1"] = rec
		b.modules = map[string]delivery.Module{}
		b.manifests = map[string][]byte{}
		for module, raw := range map[string][]byte{"restic": resticRaw, "mesh-provisioner-client": clientRaw, "store": store} {
			b.modules[module] = delivery.Module{FP2: movedFps[module], Manifest: delivery.ManifestDigest(raw)}
			b.manifests[delivery.ManifestDigest(raw)] = raw
		}
		// The vault's own answer: the client's own secret; restic's is the client's to ask, so own leaves it out.
		b.own = []compose.OwnSecretRow{{Node: "n1", Module: "mesh-provisioner-client", Name: "provisioner-broker", Origin: "made", SealedTo: "sk", Sealed: `"box"`}}
		if built {
			b.builds = map[string]*delivery.BuilderBuild{
				"restic " + movedFps["restic"]:                                   {State: delivery.BuildDone, Manifest: delivery.ManifestDigest(resticRaw), Artifacts: resticArtifacts},
				"mesh-provisioner-client " + movedFps["mesh-provisioner-client"]: {State: delivery.BuildDone, Manifest: delivery.ManifestDigest(clientRaw), Artifacts: clientArtifacts},
				"store " + movedFps["store"]:                                     {State: delivery.BuildDone, Manifest: delivery.ManifestDigest(store)},
			}
			b.archives = map[string][]byte{archiveDigest: packed.Bytes()}
		}
		return b
	}
	if _, _, err := Compose(ctx, movedMesh(false), Mesh{}, Scope{Node: "n1"}, movedFps); err == nil || !strings.Contains(err.Error(), `restic needs a secret called "repository"`) {
		t.Errorf("restic composed from the indexer's manifest: %v, want its own secret refused", err)
	}
	builtBus := movedMesh(true)
	fromBuild, _, err := Compose(ctx, builtBus, Mesh{}, Scope{Node: "n1"}, movedFps)
	if err != nil {
		t.Fatalf("restic composed from its build: %v", err)
	}
	if !reflect.DeepEqual(builtBus.fetched, []string{"http://127.0.0.1:5000/v2/restic/files/blobs/" + archiveDigest}) {
		t.Errorf("the templates archive was read at %v", builtBus.fetched)
	}
	resticKey, _ := delivery.ComposedKey("n1", "restic", movedFps["restic"])
	if c := fromBuild[resticKey]; len(c.Filled) != 4 { // its three templated files and its own secret
		t.Errorf("restic is not handed to the provisioner: its filled files are %v", c.Filled)
	}
	// The controller's: its take-in resolves each manifest with the key's artifacts and the archive's texts, and composes
	// from those over the same input.
	storeIn, err := Input(ctx, movedMesh(false), Mesh{}, Scope{Node: "n1"})
	if err != nil {
		t.Fatal(err)
	}
	for module, built := range map[string][]catalogue.Built{
		"restic": {{Name: "tools", Kind: "bundle", Reference: resticArtifacts[0].Reference, Digest: digestOf("6")},
			{Name: "files", Kind: "archive", Reference: resticArtifacts[1].Reference, Digest: archiveDigest, Texts: texts}},
		"mesh-provisioner-client": {{Name: "client", Kind: "bundle", Reference: clientArtifacts[0].Reference, Digest: digestOf("7")}},
	} {
		resolved, err := storeIn.Catalogue[module].Resolve(built)
		if err != nil {
			t.Fatal(err)
		}
		// Kept as its bytes and read again, as the controller's store holds a build's manifest.
		raw, _ := json.Marshal(resolved)
		if storeIn.Catalogue[module], err = catalogue.ParseManifestForInputs(raw); err != nil {
			t.Fatal(err)
		}
	}
	storeIn.OwnSecrets = movedMesh(true).own
	fromStoreMoved, _, err := compose.Compositions(storeIn, "n1", movedFps, compose.Reading)
	if err != nil {
		t.Fatal(err)
	}
	if !reflect.DeepEqual(fromBuild, fromStoreMoved) {
		gj, _ := json.MarshalIndent(fromBuild, "", " ")
		wj, _ := json.MarshalIndent(fromStoreMoved, "", " ")
		t.Errorf("composed from the build differs from the controller's take-in:\n got %s\nwant %s", gj, wj)
	}

	// And what a provider on another node serves from its settings (mailu's smtp domain, issue 1126: shanks refused
	// '${setting:domain} ... nothing sets "domain"'): read for that provider's served keys alone, through Served.
	mailer := []byte(`{"module":"mailer","version":"1","config":{"domain":{"type":"string","description":"the mail domain","required":true}},` +
		`"provides":[{"name":"smtp","scope":"mesh"}],"serves":{"smtp":{"port":587,"domain":"${config:domain}"}}}`)
	withMailer := func(set bool) *bus {
		b := mk()
		p := b.placements["anchor"]
		p.Modules = append(p.Modules, delivery.PlacedModule{Module: "mailer"})
		b.placements["anchor"] = p
		b.modules["mailer"] = delivery.Module{Manifest: delivery.ManifestDigest(mailer)}
		b.manifests[delivery.ManifestDigest(mailer)] = mailer
		if set {
			b.served = map[string]map[string]any{"anchor.mailer": {"domain": "example.org"}}
		}
		return b
	}
	if _, _, err := Compose(ctx, withMailer(false), Mesh{}, Scope{Node: "laptop"}, fps); err == nil || !strings.Contains(err.Error(), `nothing sets "domain"`) {
		t.Errorf("a provider's served setting nobody sets: %v", err)
	}
	served := withMailer(true)
	if _, _, err := Compose(ctx, served, Mesh{}, Scope{Node: "laptop"}, fps); err != nil {
		t.Errorf("laptop with what anchor's mailer serves: %v", err)
	}
	if !reflect.DeepEqual(served.servedRead, []string{"anchor.mailer:domain"}) || slices.Contains(served.valuesRead, "anchor.mailer") {
		t.Errorf("laptop read %v of other nodes (and %v of config values): the served keys of anchor's mailer alone", served.servedRead, served.valuesRead)
	}

	for name, c := range map[string]struct {
		change func(*bus)
		scope  Scope
		says   string
	}{
		"no record":          {func(b *bus) { delete(b.records, "laptop") }, Scope{Node: "anchor"}, "laptop, whose agent has written no record"},
		"no placement":       {func(b *bus) {}, Scope{Node: "stranger"}, "stranger has no placement"},
		"a manifest unread":  {func(b *bus) { delete(b.manifests, digest) }, Scope{Node: "laptop"}, "the manifest of xterm"},
		"a kept one unbuilt": {func(b *bus) {}, Scope{Node: "laptop", KeptAt: map[string]string{"xterm": "src2:gone"}}, "holds no done build"},
	} {
		b := mk()
		c.change(b)
		if _, err := Input(ctx, b, Mesh{}, c.scope); err == nil || !strings.Contains(err.Error(), c.says) {
			t.Errorf("%s: %v, want it to say %q", name, err, c.says)
		}
	}
}