package manifest

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io/fs"
	"maps"
	"os"
	"path/filepath"
	"slices"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/nats-io/nats.go/jetstream"

	"git.novox.be/novox/mesh-sdk/go/asker"
	"git.novox.be/novox/mesh-sdk/go/asks"
	"git.novox.be/novox/mesh-sdk/go/buscompose"
	"git.novox.be/novox/mesh-sdk/go/catalogue"
	"git.novox.be/novox/mesh-sdk/go/delivery"
	"git.novox.be/novox/mesh-sdk/go/seal"

	"mesh-grants/internal/grants"
)

// fakeBus is the bus as the part sees it: other parts' states to read (refusing those named), the bus module's read
// tools, the part's own states and its events. It records every write, call and event, so a row can prove nothing was
// published or asserted.
type fakeBus struct {
	mu       sync.Mutex
	states   map[string]map[string][]byte
	refused  map[string]bool
	loaded   []grants.User
	streams  []map[string]any
	own      map[string]map[string][]byte
	revs     map[string]uint64
	refuseTo map[string]bool
	calls    []string
	events   []string
	writes   []string
	// The assignments stream: each subject's last membership and sequence, every publish, and whether it is refused.
	stream    map[string][]byte
	seqs      map[string]uint64
	seq       uint64
	publishes []string
	refusePub bool
	// hold, when set, keeps every nats_users call waiting until it is closed: a pass waiting on the bus.
	hold chan struct{}
	// creates are the streams the part asked to create, refused when refuseCreate.
	creates      []string
	refuseCreate bool
	// refuseUsers refuses the bus module's nats_users: the loaded list cannot be read.
	refuseUsers bool
	// rootFree answers the controller's root-free verb: nil is no answerer at all (no responders).
	rootFree func(machines []string) (any, error)
	// consumers are the durable consumers the bus holds, by stream, as nats_streams answers them for one stream; and
	// consumerCreates each consumer the part asked to create, `<stream>.<name>`.
	consumers       map[string][]map[string]any
	consumerCreates []string
}

// MatchConsumer is the bus's update of a held durable consumer to the configuration given.
func (b *fakeBus) MatchConsumer(stream string, cfg jetstream.ConsumerConfig) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.consumerCreates = append(b.consumerCreates, "match "+stream+"."+cfg.Durable)
	for _, c := range b.consumers[stream] {
		if c["name"] == cfg.Durable {
			c["max_deliver"] = cfg.MaxDeliver
			return nil
		}
	}
	return errors.New("consumer not found")
}

// CreateConsumer is the bus's create of a durable consumer: held when the bus holds one of that name, else held from now.
func (b *fakeBus) CreateConsumer(stream string, cfg jetstream.ConsumerConfig) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.consumerCreates = append(b.consumerCreates, stream+"."+cfg.Durable)
	for _, c := range b.consumers[stream] {
		if c["name"] == cfg.Durable {
			return grants.ErrHeld
		}
	}
	filters := append([]string{}, cfg.FilterSubjects...)
	if cfg.FilterSubject != "" {
		filters = []string{cfg.FilterSubject}
	}
	if b.consumers == nil {
		b.consumers = map[string][]map[string]any{}
	}
	b.consumers[stream] = append(b.consumers[stream], map[string]any{"name": cfg.Durable, "filters": filters, "max_deliver": cfg.MaxDeliver})
	return nil
}

func (b *fakeBus) LastMembership(node, module string) ([]byte, uint64, bool, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	subject := "mesh.assignment." + node + "." + module
	v, ok := b.stream[subject]
	return v, b.seqs[subject], ok, nil
}

func (b *fakeBus) PublishMembership(node, module string, body []byte, after uint64) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	subject := "mesh.assignment." + node + "." + module
	if b.refusePub {
		return errors.New("Permissions Violation for Publish to " + subject)
	}
	if b.seqs[subject] != after {
		return fmt.Errorf("wrong last sequence for %s: %d", subject, b.seqs[subject])
	}
	if b.stream == nil {
		b.stream, b.seqs = map[string][]byte{}, map[string]uint64{}
	}
	b.seq++
	b.stream[subject], b.seqs[subject] = body, b.seq
	b.publishes = append(b.publishes, subject)
	return nil
}

// CreateDeclared is the bus's create of a stream: refused when refuseCreate, held when the bus holds it, and otherwise
// held from now on, as nats_streams then reads it.
func (b *fakeBus) CreateDeclared(cfg jetstream.StreamConfig) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.creates = append(b.creates, cfg.Name)
	if b.refuseCreate {
		return errors.New("Permissions Violation for Publish to $JS.API.STREAM.CREATE." + cfg.Name)
	}
	for _, s := range b.streams {
		if s["name"] == cfg.Name {
			return grants.ErrHeld
		}
	}
	b.streams = append(b.streams, map[string]any{"name": cfg.Name, "subjects": cfg.Subjects, "retention": "limits",
		"max_age_hours": int(cfg.MaxAge.Hours()), "max_per_subject": int(cfg.MaxMsgsPerSubject)})
	return nil
}

func newFakeBus() *fakeBus {
	return &fakeBus{states: map[string]map[string][]byte{}, refused: map[string]bool{}, own: map[string]map[string][]byte{},
		revs: map[string]uint64{}, refuseTo: map[string]bool{}}
}

func (b *fakeBus) put(state, key string, v any) {
	raw, err := json.Marshal(v)
	if err != nil {
		panic(err)
	}
	if b.states[state] == nil {
		b.states[state] = map[string][]byte{}
	}
	b.states[state][key] = raw
}

func (b *fakeBus) Keys(state string) ([]string, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.refused[state] {
		return nil, errors.New("Permissions Violation for Publish to $JS.API.STREAM.INFO.KV_" + state)
	}
	var out []string
	for k := range b.states[state] {
		out = append(out, k)
	}
	slices.Sort(out)
	return out, nil
}

func (b *fakeBus) Get(state, key string) ([]byte, bool, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.refused[state] {
		return nil, false, errors.New("refused")
	}
	v, ok := b.states[state][key]
	return v, ok, nil
}

func (b *fakeBus) Call(key string, body any) (json.RawMessage, error) {
	b.mu.Lock()
	hold := b.hold
	b.mu.Unlock()
	if hold != nil && key == grants.CallUsers {
		<-hold
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	b.calls = append(b.calls, key)
	args, _ := body.(map[string]any)
	switch key {
	case grants.CallUsers:
		if b.refuseUsers {
			return nil, errors.New("nats: no responders available for request")
		}
		part, _ := args["user"].(string)
		if part == "" {
			var names []map[string]any
			for _, u := range b.loaded {
				names = append(names, map[string]any{"user": u.User, "publish_grants": len(u.Publish)})
			}
			return json.Marshal(map[string]any{"users": names})
		}
		var out []grants.User
		for _, u := range b.loaded {
			if strings.Contains(u.User, part) {
				out = append(out, u)
			}
		}
		return json.Marshal(map[string]any{"users": out})
	case grants.CallStreams:
		if stream, _ := args["stream"].(string); stream != "" {
			return json.Marshal(map[string]any{"detail": []map[string]any{{"name": stream, "consumer_detail": b.consumers[stream]}}})
		}
		return json.Marshal(map[string]any{"detail": b.streams})
	case grants.CallRootFree:
		if b.rootFree == nil {
			return nil, errors.New("nats: no responders available for request")
		}
		out, err := b.rootFree(args["machines"].([]string))
		if err != nil {
			return nil, err
		}
		return json.Marshal(out)
	}
	return nil, fmt.Errorf("no tool %s", key)
}

func (b *fakeBus) ownGet(state, key string) ([]byte, uint64, bool, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	v, ok := b.own[state][key]
	return v, b.revs[state+"/"+key], ok, nil
}

type ownStore struct{ b *fakeBus }

func (s ownStore) Get(state, key string) ([]byte, uint64, bool, error) { return s.b.ownGet(state, key) }
func (s ownStore) Put(state, key string, value []byte) (uint64, error) {
	b := s.b
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.refuseTo[state] {
		return 0, errors.New("Permissions Violation for Publish to $KV.mesh-grants_" + state)
	}
	b.writes = append(b.writes, state)
	if b.own[state] == nil {
		b.own[state] = map[string][]byte{}
	}
	b.own[state][key] = value
	b.revs[state+"/"+key]++
	return b.revs[state+"/"+key], nil
}

func (s ownStore) Keys(state string) ([]string, error) {
	b := s.b
	b.mu.Lock()
	defer b.mu.Unlock()
	var out []string
	for k := range b.own[state] {
		out = append(out, k)
	}
	slices.Sort(out)
	return out, nil
}

func (s ownStore) Delete(state, key string) error {
	b := s.b
	b.mu.Lock()
	defer b.mu.Unlock()
	b.writes = append(b.writes, state+" delete")
	delete(b.own[state], key)
	return nil
}

func (b *fakeBus) Emit(event string, _ any) error {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.events = append(b.events, event)
	return nil
}

func (b *fakeBus) count(key string) int {
	b.mu.Lock()
	defer b.mu.Unlock()
	n := 0
	for _, c := range b.calls {
		if c == key {
			n++
		}
	}
	return n
}

// manifestOf is a fixture manifest of one module, in the indexer's two buckets.
func (b *fakeBus) manifestOf(module, raw string) {
	digest := delivery.ManifestDigest([]byte(raw))
	b.put(grants.ReadManifests, digest, delivery.Manifest{V: delivery.Version, Module: module, JSON: raw})
	b.put(grants.ReadModules, module, delivery.Module{V: delivery.Version, FP2: "src2:" + strings.Repeat("ab", 32), Manifest: digest, Repository: "novox/x", Commit: "c"})
}

func (b *fakeBus) assign(node, module string) {
	b.put(grants.ReadAssignments, node+"."+module, map[string]any{"node": node, "module": module, "assigned": "2026-10-25T20:00:00Z"})
}

const (
	natsManifest = `{"module":"nats","version":"1","claims":[{"name":"mesh-broker"}],"own-secrets":{"broker":"/var/lib/nats/broker"}}`
	xManifest    = `{"module":"mod-x","version":"1","own-secrets":{"broker":"/var/lib/x/broker"},"state":[{"name":"kept","history":3}],` +
		`"streams":[{"name":"things","events":["thing.added"],"max-age-days":2,"max-mib":5}],"logs":[{"name":"history"}]}`
	yManifest = `{"module":"mod-y","version":"1","own-secrets":{"broker":"/var/lib/y/broker"},"reads":["mod-x.kept"]}`
)

// brokerSeat is one verb of the bus's seat as a membership serves it: nats claims the seat in fixture and no membership
// composed there serves it, so a membership or list that drops it leaves the seat with no holder (issue 1945).
func brokerSeat() (seat, verb string) {
	s, _ := catalogue.SeatNamed(catalogue.BrokerSeat)
	verb = "v"
	if len(s.Serves) > 0 {
		verb = s.Serves[0].Name
	}
	return s.Name, verb
}

// fixture is a mesh of two machines: a runs the bus and mod-x, b runs mod-y; the bus node's agent loaded a list.
func fixture() *fakeBus {
	b := newFakeBus()
	b.manifestOf("nats", natsManifest)
	b.manifestOf("mod-x", xManifest)
	b.manifestOf("mod-y", yManifest)
	b.assign("a", "nats")
	b.assign("a", "mod-x")
	b.assign("b", "mod-y")
	b.put(grants.ReadAssignments, "b.gone", map[string]any{"node": "b", "module": "gone", "assigned": "2026-10-01T00:00:00Z", "ended": "2026-10-02T00:00:00Z"})
	b.put(grants.ReadHave, "a.node", map[string]any{"v": 1})
	b.put(grants.ReadHave, "b.node", map[string]any{"v": 1})
	b.put(grants.ReadHave, "a.nats", delivery.Have{V: delivery.Version, Phase: delivery.PhaseRunning, Health: delivery.HealthOK,
		UserList: &delivery.UserListWritten{Source: "a.nats.src2", Revision: 7, Wanted: "sha256:aa", Digest: "sha256:aa", Users: 6}})
	b.put(grants.ReadControllerGrant, "mod-x.0123456789ab0123456789ab0123456789ab0123456789ab0123456789ab0123", delivery.ControllerGrant{V: delivery.Version, Accounts: []string{"a.mod-x"}})
	return b
}

func partOn(b *fakeBus) *grants.Part {
	return &grants.Part{Read: b, Call: b, Store: ownStore{b}, Emit: b, Publish: b, Now: func() time.Time { return time.Date(2026, 10, 25, 22, 0, 0, 0, time.UTC) }}
}

// shadowOf is the list the part composes from b's records now.
func shadowOf(t *testing.T, b *fakeBus) []grants.User {
	t.Helper()
	recs, _ := grants.Records(grants.ReadInputs(b, &grants.Manifests{}))
	users, err := grants.ComposeUsers(recs)
	if err != nil {
		t.Fatal(err)
	}
	return users
}

func names(us []grants.User) []string {
	var out []string
	for _, u := range us {
		out = append(out, u.User)
	}
	return out
}

func gapNamed(gs []grants.Gap, input string) bool {
	return slices.ContainsFunc(gs, func(g grants.Gap) bool { return strings.Contains(g.Input, input) })
}

// TestGrants is the grants part's one table of checks (ADR 0547 clauses 5 to 8 in shadow, issue 1945): its manifest,
// the shadow list composed from bus values, the compare, each tool, that nothing is published or asserted, and that a
// refused read or write never stops it.
func TestGrants(t *testing.T) {
	t.Run("manifest", func(t *testing.T) {
		raw, err := os.ReadFile("module.json")
		if err != nil {
			t.Fatal(err)
		}
		m, err := catalogue.ParseManifest(raw)
		if err != nil {
			t.Fatalf("mesh-sdk's manifest reader refuses the manifest: %v", err)
		}
		if m.Module != "mesh-grants" || len(m.Claims) != 0 {
			t.Errorf("module %q claims %v: the part claims no seat until mesh-sdk's seat list names mesh-grants", m.Module, m.Claims)
		}
		for _, row := range []struct {
			what      string
			got, want []string
		}{
			{"reads", m.Reads, grants.Reads},
			{"invokes", m.Invokes, grants.Invokes},
			{"consumes", m.Consumes, grants.Consumes},
			{"emits", m.Emits, grants.Emits},
			{"tools", m.Tools, grants.Tools},
		} {
			if !slices.Equal(slices.Sorted(slices.Values(row.got)), slices.Sorted(slices.Values(row.want))) {
				t.Errorf("%s = %v, the program's are %v", row.what, row.got, row.want)
			}
		}
		var states []string
		for _, s := range m.State {
			states = append(states, s.Name)
		}
		if !slices.Equal(slices.Sorted(slices.Values(states)), grants.States) {
			t.Errorf("state = %v, want %v", states, grants.States)
		}
		if _, ok := m.OwnSecrets["broker"]; !ok || len(m.OwnSecrets) != 1 || m.SecretsOwner != "mesh-grants" {
			t.Errorf("own-secrets %v owner %q: a credential of its own, broker", m.OwnSecrets, m.SecretsOwner)
		}
	})

	t.Run("no timer, no update or delete, a publish only of memberships, a create only of declared streams", func(t *testing.T) {
		forbidden := []string{"time.Tick", "time.NewTicker", "time.Sleep", "time.After", "time.NewTimer", "time.AfterFunc",
			"PublishMsg", "CreateKeyValue", "CreateOrUpdate", "UpdateStream", "UpdateKeyValue", "DeleteStream", "PurgeStream",
			"DeleteKeyValue", "CreateObjectStore", "EnsureStream", "RaiseBuckets", "RaiseLogs", ".Create("}
		// The one publish: a membership, on its own subject, in publish.go; the one create: a declared stream the bus lacks,
		// in create.go (issue 1790).
		publishOnly := filepath.Join("cmd", "mesh-grants", "publish.go")
		createOnly := filepath.Join("cmd", "mesh-grants", "create.go")
		// And the operator's asks and conditions, on the seat operator-channel's subjects, in asking.go (ADR 0547 clause 8).
		asksOnly := filepath.Join("cmd", "mesh-grants", "asking.go")
		sealedOnly := filepath.Join("cmd", "mesh-grants", "sealed.go")
		files := 0
		for _, root := range []string{"cmd", "internal"} {
			err := filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
				if err != nil || d.IsDir() || !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "_test.go") {
					return err
				}
				files++
				src, err := os.ReadFile(path)
				if path != publishOnly && path != asksOnly && (strings.Contains(string(src), ".Publish(") || strings.Contains(string(src), "mesh.assignment")) {
					t.Errorf("%s publishes: only publish.go publishes memberships, and asking.go the operator's asks", path)
				}
				if path == asksOnly && (strings.Count(string(src), ".Publish(") != 2 || strings.Contains(string(src), "mesh.assignment")) {
					t.Errorf("asking.go publishes other than an ask, a cancel and a condition, through js.Publish twice")
				}
				if path == publishOnly && strings.Count(string(src), ".Publish(") != 1 {
					t.Errorf("publish.go publishes other than one membership")
				}
				if n := strings.Count(string(src), "CreateStream"); (path == createOnly && n != 1) || (path != createOnly && n != 0) {
					t.Errorf("%s holds CreateStream %d times: only create.go creates, once", path, n)
				}
				// The one object bucket: the part's own, of the user list sealed to the bus node, in sealed.go (ADR 0547 clause 7).
				if path == sealedOnly {
					if strings.Count(string(src), "CreateObjectStore(") != 1 || !strings.Contains(string(src), "delivery.GrantsUserListObjects") {
						t.Errorf("sealed.go creates other than the part's one object bucket")
					}
					src = []byte(strings.ReplaceAll(string(src), "CreateObjectStore", ""))
				}
				for _, f := range forbidden {
					if strings.Contains(string(src), f) {
						t.Errorf("%s holds %s: the part holds no timer and creates or asserts nothing", path, f)
					}
				}
				return err
			})
			if err != nil {
				t.Fatal(err)
			}
		}
		if files < 8 {
			t.Fatalf("read %d source files, want the program's", files)
		}
	})

	t.Run("shadow list from bus values", func(t *testing.T) {
		for _, row := range []struct {
			name  string
			bend  func(*fakeBus)
			users []string
			gap   string
		}{
			{"every record on the bus", func(*fakeBus) {},
				[]string{"a.mod-x", "a.nats", "b.mod-y", "controller", "node.a", "node.b"}, "enrolment tokens"},
			{"a manifest missing is a gap and its user is left out", func(b *fakeBus) { delete(b.states[grants.ReadModules], "mod-y") },
				[]string{"a.mod-x", "a.nats", "controller", "node.a", "node.b"}, "manifest of mod-y"},
			{"a want's built manifest is composed, not the trunk's", func(b *fakeBus) {
				built := strings.Replace(xManifest, `"history":3}]`, `"history":3},{"name":"newer"}]`, 1)
				digest := delivery.ManifestDigest([]byte(built))
				b.put(grants.ReadManifests, digest, delivery.Manifest{V: delivery.Version, Module: "mod-x", JSON: built})
				fp := "src2:" + strings.Repeat("cd", 32)
				b.put(grants.ReadWants, "want.a.mod-x", delivery.Want{V: delivery.Version, FP: fp, Composed: "sha256:" + strings.Repeat("ef", 32)})
				key, _ := delivery.BuilderBuildKey("mod-x", fp)
				b.put(grants.ReadBuilds, key, map[string]any{"v": delivery.Version, "state": "done", "manifest": digest})
			}, []string{"a.mod-x", "a.nats", "b.mod-y", "controller", "node.a", "node.b"}, "enrolment tokens"},
			{"placement refused is a gap; the machines come from the haves", func(b *fakeBus) { b.refused[grants.ReadAssignments] = true },
				[]string{"controller", "node.a", "node.b"}, grants.ReadAssignments},
		} {
			t.Run(row.name, func(t *testing.T) {
				b := fixture()
				row.bend(b)
				in := grants.ReadInputs(b, &grants.Manifests{})
				recs, left := grants.Records(in)
				users, err := grants.ComposeUsers(recs)
				if err != nil {
					t.Fatal(err)
				}
				if got := names(users); !slices.Equal(got, row.users) {
					t.Errorf("users = %v, want %v", got, row.users)
				}
				if !gapNamed(append(in.Gaps, left...), row.gap) {
					t.Errorf("gaps %v name no %q", in.Gaps, row.gap)
				}
				if strings.HasPrefix(row.name, "a want's") {
					x := users[slices.IndexFunc(users, func(u grants.User) bool { return u.User == "a.mod-x" })]
					if !slices.Contains(x.Publish, "$KV.mod-x_newer.>") {
						t.Errorf("a.mod-x is not granted the state its wanted build declares: %v", x.Publish)
					}
				}
			})
		}
		// A module whose only runtime-loaded part is a helper bundle (route-proxy's route-provider) says `loads` in
		// the repository manifest's build.artifacts; the indexer's manifest has no derived Bundles (issue 1945).
		for _, row := range []struct {
			name, build string
			carried     bool
		}{
			{"a bundle that says loads is carried by node-tools", `,"build":{"artifacts":[{"name":"helper","kind":"bundle","language":"go","system":"arch","from":"cmd/h","binary":"h","loads":["h"]}]}`, true},
			{"a module with no loading bundle is left to its own account", ``, false},
		} {
			t.Run(row.name, func(t *testing.T) {
				b := fixture()
				b.manifestOf("mod-z", `{"module":"mod-z","version":"1","own-secrets":{"broker":"/var/lib/z/broker"}`+row.build+`}`)
				b.assign("a", "mod-z")
				b.manifestOf("node-tools", `{"module":"node-tools","version":"1","own-secrets":{"broker":"/var/lib/nt/broker"}}`)
				b.assign("a", "node-tools")
				users := shadowOf(t, b)
				tools := users[slices.IndexFunc(users, func(u grants.User) bool { return u.User == "a.node-tools" })]
				if got := slices.Contains(tools.Subscribe, "mesh.mod.mod-z.tool.>"); got != row.carried {
					t.Errorf("a.node-tools subscribes to mod-z's tools = %v, want %v: %v", got, row.carried, tools.Subscribe)
				}
			})
		}
		// ADR 0559 §3 (issue 1126): the indexer's placement candidates are read by every node agent (mesh-sdk
		// NodeComposeReads), the assigner and the status view, each by its manifest's reads, and by no other module.
		cands := fixture()
		cands.manifestOf("mesh-delivery-indexer", `{"module":"mesh-delivery-indexer","version":"1","own-secrets":{"broker":"/var/lib/i/broker"},"state":[{"name":"placement-candidates","history":5}]}`)
		cands.manifestOf("mesh-delivery-assigner", `{"module":"mesh-delivery-assigner","version":"1","own-secrets":{"broker":"/var/lib/as/broker"},"reads":["mesh-delivery-indexer.placement-candidates"]}`)
		cands.manifestOf("mesh-delivery-view", `{"module":"mesh-delivery-view","version":"1","own-secrets":{"broker":"/var/lib/v/broker"},"reads":["mesh-delivery-indexer.placement-candidates"]}`)
		for _, m := range []string{"mesh-delivery-indexer", "mesh-delivery-assigner", "mesh-delivery-view"} {
			cands.assign("a", m)
		}
		var readers []string
		for _, u := range shadowOf(t, cands) {
			if slices.Contains(u.Publish, "$JS.API.DIRECT.GET.KV_"+delivery.PlacementCandidatesBucket+".>") {
				readers = append(readers, u.User)
			}
		}
		if want := []string{"a.mesh-delivery-assigner", "a.mesh-delivery-indexer", "a.mesh-delivery-view", "node.a", "node.b"}; !slices.Equal(readers, want) {
			t.Errorf("the placement candidates are read by %v, want the node agents, the assigner, the view and their writer %v", readers, want)
		}
		b := fixture()
		users := shadowOf(t, b)
		y := users[slices.IndexFunc(users, func(u grants.User) bool { return u.User == "b.mod-y" })]
		if !slices.Contains(y.Publish, "$JS.API.DIRECT.GET.KV_mod-x_kept.>") {
			t.Errorf("b.mod-y reads mod-x.kept and is not granted its direct get: %v", y.Publish)
		}
	})

	t.Run("root-free: the controller's word fills the composition, failing closed (issue 1945)", func(t *testing.T) {
		const router = `{"module":"messenger","version":"1","runs-as":"messenger","resources":[{"id":"account","type":"user","name":"messenger","shell":"/usr/bin/nologin","home":"/var/lib/messenger"}],"own-secrets":{"broker":"/var/lib/m/broker"},"secrets-owner":"messenger",` +
			`"seats":[{"name":"operator-channel","scope":"mesh","serves":["open"]},{"name":"channel","scope":"mesh","kinded":true,"accepts":["show"]}],` +
			`"claims":[{"name":"operator-channel","scope":"mesh","serves":["open"]}]}`
		const telegram = `{"module":"telegram","version":"1","runs-as":"telegram","resources":[{"id":"account","type":"user","name":"telegram","shell":"/usr/bin/nologin","home":"/var/lib/telegram"}],"own-secrets":{"broker":"/var/lib/t/broker"},"secrets-owner":"telegram",` +
			`"claims":[{"name":"channel","scope":"mesh","kind":"telegram","capabilities":["deliver","verified-sender"]}]}`
		answer := func(free ...string) func([]string) (any, error) {
			return func(machines []string) (any, error) {
				var vs []map[string]any
				for _, m := range machines {
					ok := slices.Contains(free, m)
					why := "judged free"
					if !ok {
						why = "its node-engine judged nothing"
					}
					vs = append(vs, map[string]any{"machine": m, "free": ok, "why": why})
				}
				return map[string]any{"machines": vs}, nil
			}
		}
		for _, row := range []struct {
			name       string
			routerOn   []string
			telegramOn string
			ask        func([]string) (any, error)
			keeps      bool
			note       string
		}{
			{"router and telegram on one free machine", []string{"a"}, "a", answer("a"), true, ""},
			{"router and telegram on two free machines", []string{"a"}, "b", answer("a", "b"), true, ""},
			{"the holder's machine is not free", []string{"a"}, "b", answer("a"), false, "b: not free, its node-engine judged nothing"},
			{"the router's machine is not free", []string{"a"}, "b", answer("b"), false, "a: not free"},
			{"an error is not free", []string{"a"}, "a", func([]string) (any, error) { return nil, errors.New("boom") }, false, "boom"},
			{"no answerer is not free", []string{"a"}, "a", nil, false, "no responders"},
			{"a machine left out of the answer is not free", []string{"a"}, "a",
				func([]string) (any, error) { return map[string]any{"machines": []any{}}, nil }, false, "named no verdict"},
			{"the router on two machines frees nothing", []string{"a", "b"}, "a", answer("a", "b"), false, ""},
		} {
			t.Run(row.name, func(t *testing.T) {
				b := fixture()
				b.manifestOf("messenger", router)
				b.manifestOf("telegram", telegram)
				for _, node := range row.routerOn {
					b.assign(node, "messenger")
				}
				b.assign(row.telegramOn, "telegram")
				b.rootFree = row.ask
				res := partOn(b).Compose()
				recs, _ := grants.Records(grants.ReadInputs(b, &grants.Manifests{}))
				grants.WithRootFree(&recs, b)
				kept := false
				for _, k := range buscompose.PlacementsOf(recs, recs.Interchangeable).Kinds {
					kept = kept || slices.Contains(k.Capabilities, "verified-sender")
				}
				if kept != row.keeps {
					t.Errorf("verified-sender kept = %v, want %v (said %v)", kept, row.keeps, res.RootNotFree)
				}
				if !strings.Contains(strings.Join(res.RootNotFree, " | "), row.note) || (row.note == "" && row.keeps && len(res.RootNotFree) != 0) {
					t.Errorf("the pass says %v, want it to name %q", res.RootNotFree, row.note)
				}
			})
		}
		// A root-not-free condition raised or cleared wakes a pass; another kind does not (never a timer).
		wb := fixture()
		var handle func(string, []byte)
		wf := &grants.Follower{Part: partOn(wb), Watch: &fakeWatcher{opened: make(chan string, 16)}, Logf: func(string, ...any) {},
			Hear: func(h func(string, []byte)) error { handle = h; return nil }}
		wctx, wcancel := context.WithCancel(context.Background())
		wdone := make(chan struct{})
		go func() { wf.Run(wctx); close(wdone) }()
		waitFor(t, func() bool { return wb.count(grants.CallUsers) > 0 && handle != nil })
		passes := func() int { return wb.count(grants.CallUsers) }
		before := passes()
		handle(grants.EventConditionRaised, []byte(`{"kind":"disk-full","key":"machine.a.disk-full"}`))
		time.Sleep(100 * time.Millisecond)
		if passes() != before {
			t.Errorf("a condition of another kind woke a pass")
		}
		handle(grants.EventConditionCleared, []byte(`{"kind":"root-not-free","key":"machine.a.root-not-free"}`))
		waitFor(t, func() bool { return passes() > before })
		wcancel()
		<-wdone
		if !grants.IsRootNotFree([]byte(`{"kind":"root-not-free"}`)) || !grants.IsRootNotFree([]byte(`{"key":"machine.novox.root-not-free"}`)) ||
			grants.IsRootNotFree([]byte(`{"kind":"disk-full","key":"machine.novox.disk-full"}`)) {
			t.Errorf("only a root-not-free condition wakes a pass")
		}
	})

	t.Run("a predefined-key fallback is read with no list; every refused manifest listed", func(t *testing.T) {
		// mod-p's value falls back to a predefined key, as claude-code's managed_settings does, and no list is on the bus
		// (issue 1945); mod-z's manifest carries a key mesh-sdk's reader refuses, and mod-z is assigned nowhere.
		const pManifest = `{"module":"mod-p","version":"1","own-secrets":{"broker":"/var/lib/p/broker"},` +
			`"config":{"size":{"type":"number","description":"The size text shows in, in points.","predefined":"font-size","default":12,"runtime":true}}}`
		const zManifest = `{"module":"mod-z","version":"1","no-such-key":true}`
		b := fixture()
		b.manifestOf("mod-p", pManifest)
		b.manifestOf("mod-z", zManifest)
		b.assign("b", "mod-p")
		// mesh-wireguard is provided by the mesh, not read from a repository: no manifest in the indexer, none refused,
		// no gap, and its manifest is the one mesh-sdk provides (issue 1945).
		b.assign("b", "mesh-wireguard")
		in := grants.ReadInputs(b, &grants.Manifests{})
		// An indexer row of the same name never wins: the provided manifest is used and the row is said as a gap.
		bw := fixture()
		bw.manifestOf("mesh-wireguard", `{"module":"mesh-wireguard","version":"9","own-secrets":{"broker":"/x"}}`)
		bw.assign("b", "mesh-wireguard")
		if iw := grants.ReadInputs(bw, &grants.Manifests{}); !strings.HasPrefix(iw.Digests["mesh-wireguard"], "provided:") || !gapNamed(iw.Gaps, "manifest of mesh-wireguard") || len(iw.Refused) != 0 {
			t.Errorf("an indexer manifest of mesh-wireguard won or went unsaid: %v %v", iw.Digests["mesh-wireguard"], iw.Gaps)
		}
		if _, ok := in.Manifests["mesh-wireguard"]; !ok || gapNamed(in.Gaps, "manifest of mesh-wireguard") || !strings.HasPrefix(in.Digests["mesh-wireguard"], "provided:") {
			t.Errorf("mesh-wireguard's manifest is not taken from mesh-sdk: gaps %v", in.Gaps)
		}
		if len(in.Refused) != 1 || in.Refused[0].Input != "manifest of mod-z" || !gapNamed(in.Gaps, "manifest of mod-z") {
			t.Errorf("refused = %v: only mod-z's, and named in the gaps", in.Refused)
		}
		recs, _ := grants.Records(in)
		users, err := grants.ComposeUsers(recs)
		if err != nil {
			t.Fatal(err)
		}
		if !slices.Contains(names(users), "b.mod-p") {
			t.Errorf("b.mod-p is not composed, so its module counts as placed nowhere: %v", names(users))
		}
		// Issue 1126: a key a module's served value fills from its settings (mailu's smtp domain) is granted to every other
		// node's agent, that key alone, so a node composing a consumer elsewhere settles what it serves.
		bs := fixture()
		bs.manifestOf("mod-s", `{"module":"mod-s","version":"1","own-secrets":{"broker":"/var/lib/s/broker"},`+
			`"config":{"domain":{"type":"string","description":"The mail domain.","required":true}},`+
			`"provides":[{"name":"smtp","scope":"mesh"}],"serves":{"smtp":{"port":587,"domain":"${config:domain}"}}}`)
		bs.assign("b", "mod-s")
		served := "$JS.API.DIRECT.GET.KV_mesh-config_resolved.$KV.mesh-config_resolved.b.mod-s.domain"
		for _, u := range shadowOf(t, bs) {
			if (u.User == "node.a") != slices.Contains(u.Publish, served) {
				t.Errorf("%s is granted b's mod-s domain: %v (node a alone)", u.User, slices.Contains(u.Publish, served))
			}
		}
		// The provider not yet moved: it runs a build whose manifest serves no setting, and the trunk's adds one, which a
		// node composing a consumer reads (frombus reads the trunk's manifest of another node's module): granted too.
		bt := fixture()
		const oldS = `{"module":"mod-s","version":"1","own-secrets":{"broker":"/var/lib/s/broker"},` +
			`"provides":[{"name":"smtp","scope":"mesh"}],"serves":{"smtp":{"port":587}}}`
		bt.manifestOf("mod-s", oldS)
		oldDigest := delivery.ManifestDigest([]byte(oldS))
		bt.manifestOf("mod-s", `{"module":"mod-s","version":"1","own-secrets":{"broker":"/var/lib/s/broker"},`+
			`"config":{"domain":{"type":"string","description":"The mail domain.","required":true}},`+
			`"provides":[{"name":"smtp","scope":"mesh"}],"serves":{"smtp":{"port":587,"domain":"${config:domain}"}}}`)
		bt.assign("b", "mod-s")
		runsFP := "src2:" + strings.Repeat("cd", 32)
		bt.put(grants.ReadWants, "want.b.mod-s", delivery.Want{V: delivery.Version, FP: runsFP, Composed: "sha256:" + strings.Repeat("ef", 32)})
		runsKey, _ := delivery.BuilderBuildKey("mod-s", runsFP)
		bt.put(grants.ReadBuilds, runsKey, map[string]any{"v": delivery.Version, "state": "done", "manifest": oldDigest})
		for _, u := range shadowOf(t, bt) {
			if u.User == "node.a" && !slices.Contains(u.Publish, served) {
				t.Errorf("node a is not granted the domain the trunk's mod-s serves, while b runs one that serves none")
			}
		}
		// The pass, the tool listing held memberships, and the log each say the refusal.
		part := partOn(b)
		res := part.Pass()
		if len(res.Refused) != 1 || !strings.HasPrefix(res.Refused[0], "manifest of mod-z: ") {
			t.Errorf("the pass says refused %v", res.Refused)
		}
		held, err := part.Held()
		if err != nil {
			t.Fatal(err)
		}
		if got, _ := held.(map[string]any)["refused"].([]string); len(got) != 1 {
			t.Errorf("grants_membership lists refused %v", got)
		}
		var logged []string
		var lmu sync.Mutex
		f := &grants.Follower{Part: partOn(b), Watch: &fakeWatcher{opened: make(chan string, 16)}, Logf: func(format string, args ...any) {
			lmu.Lock()
			logged = append(logged, fmt.Sprintf(format, args...))
			lmu.Unlock()
		}}
		ctx, cancel := context.WithCancel(context.Background())
		done := make(chan struct{})
		go func() { f.Run(ctx); close(done) }()
		waitFor(t, func() bool {
			lmu.Lock()
			defer lmu.Unlock()
			return strings.Contains(strings.Join(logged, "\n"), "refused manifest of mod-z: ")
		})
		cancel()
		<-done
	})

	t.Run("credentials", func(t *testing.T) {
		shadow := []grants.User{{User: "a.held"}, {User: "a.new"}, {User: "a.bare"}}
		loaded := []grants.User{{User: "a.held"}, {User: "a.bare"}, {User: "enrol.x"}, {User: "person.op"}}
		hashes := map[string]grants.HeldHash{"a.held": {Hash: "$2a$10$h1", Generation: 2}, "a.new": {Hash: "$2a$10$h2", Generation: 1},
			"person.op": {Hash: "$2a$10$h3", Adopted: true}}
		c := grants.CredentialsOf(shadow, loaded, hashes)
		for _, row := range []struct {
			user, would   string
			held, adopted bool
		}{
			{"a.bare", grants.WouldLeaveOut, false, false},
			{"a.held", grants.WouldSame, true, false},
			{"a.new", grants.WouldAdd, true, false},
			{"enrol.x", grants.WouldLoseLogin, false, false},
			{"person.op", grants.WouldNotComposed, true, true},
		} {
			i := slices.IndexFunc(c.Users, func(u grants.Credential) bool { return u.User == row.user })
			if i < 0 || c.Users[i].Would != row.would || c.Users[i].HashHeld != row.held || c.Users[i].Adopted != row.adopted {
				t.Errorf("%s: %+v, want %s held %v", row.user, c.Users, row.would, row.held)
			}
		}
		if c.HashesHeld != 3 || !slices.Equal(c.LeftOut, []string{"a.bare"}) || !slices.Equal(c.LosesLogin, []string{"enrol.x"}) ||
			!slices.Equal(c.Adds, []string{"a.new"}) {
			t.Errorf("credentials = %+v", c)
		}
		// Composed from the vault's state: a hash changes the list's state (written on the event), and no hash is ever
		// in what the part writes or says.
		b := fixture()
		b.loaded = shadowOf(t, b)
		p := partOn(b)
		before := p.Compose()
		b.put(grants.ReadAccounts, "a.mod-x", map[string]any{"user": "a.mod-x", "hash": "$2a$10$secrethashbytes", "generation": 1})
		after := p.Compose()
		cr := after.UserList.Credentials
		if !after.Written || after.Revision != before.Revision+1 || cr.HashesHeld != 1 || slices.Contains(cr.LeftOut, "a.mod-x") ||
			!slices.Contains(cr.LeftOut, "b.mod-y") {
			t.Errorf("a hash heard = %+v", after.UserList.Credentials)
		}
		why := strings.Join(p.Decide(), "; ")
		if !strings.Contains(why, "no hash for") || strings.Contains(why, "a.mod-x,") {
			t.Errorf("take-over is refused for %q, want the users with no hash named", why)
		}
		for state, keys := range b.own {
			for k, v := range keys {
				if strings.Contains(string(v), "secrethashbytes") {
					t.Errorf("the hash is written in %s %s", state, k)
				}
			}
		}
	})

	t.Run("compare", func(t *testing.T) {
		b := fixture()
		shadow := shadowOf(t, b)
		in := grants.ReadInputs(b, &grants.Manifests{})
		changed := slices.Clone(shadow)
		x := slices.IndexFunc(changed, func(u grants.User) bool { return u.User == "a.mod-x" })
		changed[x].Publish = append(slices.Clone(changed[x].Publish[1:]), "extra.subject")
		for _, row := range []struct {
			name                 string
			loaded               []grants.User
			added, dropped, gone []string
			differ               []string
			equal                bool
		}{
			{"equal", shadow, nil, nil, nil, nil, true},
			{"one user the bus lacks", shadow[1:], []string{shadow[0].User}, nil, nil, nil, false},
			{"one loaded user still placed", append(slices.Clone(shadow), grants.User{User: "a.mod-x.worker"}), nil, []string{"a.mod-x.worker"}, nil, nil, false},
			{"one loaded user placement no longer names", append(slices.Clone(shadow), grants.User{User: "b.gone"}), nil, []string{"b.gone"}, []string{"b.gone"}, nil, true},
			{"grants differ", changed, nil, nil, nil, []string{"a.mod-x"}, false},
		} {
			t.Run(row.name, func(t *testing.T) {
				c := grants.Compare(shadow, row.loaded, grants.Placed(in))
				var differ []string
				for _, d := range c.Differ {
					differ = append(differ, d.User)
				}
				if !slices.Equal(c.Added, nonNil(row.added)) || !slices.Equal(c.Dropped, nonNil(row.dropped)) ||
					!slices.Equal(c.Gone, row.gone) || !slices.Equal(differ, row.differ) || c.Equal() != row.equal {
					t.Errorf("compare = %+v", c)
				}
				if row.name == "grants differ" && (len(c.Differ[0].PublishAdded) != 1 || c.Differ[0].PublishDropped[0] != "extra.subject") {
					t.Errorf("the grant difference is not named: %+v", c.Differ[0])
				}
			})
		}
	})

	// 1126 (ADR 0549 §1, §3): once the catalogue places the nodes, a seat held once for the mesh is held where placement
	// says, not on every machine running a module that claims it; what placement adds is composed beside the assignments.
	t.Run("a mesh seat is held where placement says", func(t *testing.T) {
		store := catalogue.Manifest{Module: "store", Version: "1",
			DefinesSeats: []catalogue.SeatDeclaration{{Name: "store-seat", Scope: catalogue.ScopeMesh, Serves: []catalogue.Verb{{Name: "databases"}}}},
			Claims:       []catalogue.Claim{{Name: "store-seat", Scope: catalogue.ScopeMesh}}}
		in := grants.Inputs{Nodes: []string{"a", "b"}, Assigned: map[string][]string{"a": {"store"}, "b": {"store"}},
			Manifests: map[string]catalogue.Manifest{"store": store}}
		holds := func(recs buscompose.Records, node string) int {
			n := 0
			for _, d := range recs.Assigned[node] {
				n += len(d.Holds)
			}
			return n
		}
		if recs, _ := grants.Records(in); holds(recs, "a") != 1 || holds(recs, "b") != 1 {
			t.Fatalf("before placement the seat is held on a %d and b %d times, want both", holds(recs, "a"), holds(recs, "b"))
		}
		in.Placed = map[string]delivery.Placement{
			"a": {Node: "a", Modules: []delivery.PlacedModule{{Module: "store"}}, Holds: []delivery.Holding{{Claim: "store-seat", Scope: "mesh", Module: "store"}}},
			"b": {Node: "b", Modules: []delivery.PlacedModule{{Module: "store"}}}}
		if recs, _ := grants.Records(in); holds(recs, "a") != 1 || holds(recs, "b") != 0 {
			t.Errorf("placed, the seat is held on a %d and b %d times, want a alone", holds(recs, "a"), holds(recs, "b"))
		}
		b := fixture()
		pl, _ := delivery.EncodePlacement(delivery.Placement{Node: "b", Modules: []delivery.PlacedModule{{Module: "mod-y"}, {Module: "mod-x"}}})
		b.states[grants.ReadPlacement] = map[string][]byte{"placement.b": pl}
		read := grants.ReadInputs(b, &grants.Manifests{})
		if !slices.Contains(read.Assigned["b"], "mod-x") || read.Placed["b"].Node != "b" || slices.ContainsFunc(read.Gaps, func(g grants.Gap) bool { return g.Input == "seat holdings" }) {
			t.Errorf("read: assigned %v, placed %v, gaps %v", read.Assigned, read.Placed, read.Gaps)
		}
		b.refused[grants.ReadPlacement] = true
		if read := grants.ReadInputs(b, &grants.Manifests{}); slices.ContainsFunc(read.Gaps, func(g grants.Gap) bool { return g.Input == grants.ReadPlacement && g.Failed }) {
			t.Errorf("placement not on the bus is a failed read: %v", read.Gaps)
		}
		// Issue 1945, the user list of 2026-10-27 09:21: a placement's holds are the holders on record, not every holder.
		// A mesh seat no placement holds keeps the module claiming it as its holder, wherever placement puts it.
		in.Manifests["other"] = catalogue.Manifest{Module: "other", Version: "1", Claims: []catalogue.Claim{{Name: "other-seat", Scope: catalogue.ScopeMesh}},
			DefinesSeats: []catalogue.SeatDeclaration{{Name: "other-seat", Scope: catalogue.ScopeMesh, Serves: []catalogue.Verb{{Name: "v"}}}}}
		in.Assigned["b"] = append(in.Assigned["b"], "other")
		in.Placed["b"] = delivery.Placement{Node: "b", Modules: []delivery.PlacedModule{{Module: "store"}, {Module: "other"}}}
		if recs, _ := grants.Records(in); holds(recs, "a") != 1 || holds(recs, "b") != 1 {
			t.Errorf("a seat no placement holds is held on b %d times, want once (and store-seat on a alone: a %d)", holds(recs, "b"), holds(recs, "a"))
		}
		in.Placed["b"] = delivery.Placement{Node: "b", Modules: []delivery.PlacedModule{{Module: "store"}, {Module: "other"}},
			Holds: []delivery.Holding{{Claim: "other-seat", Scope: "mesh", Module: "someone-else"}}}
		if recs, _ := grants.Records(in); holds(recs, "b") != 0 {
			t.Errorf("a seat placement holds by another module is still held by other on b")
		}
		// The live shapes: the seed's novox placement (mesh-catalog 0c61bad, its twelve holdings, without
		// anthropic-licence-manager), the licence manager's manifest (mesh-catalog c05aa5e6), and the subjects the bus
		// grants novox.node-tools for its seat (nats_users, 2026-10-27 19:40Z).
		file := func(name string, v any) {
			raw, err := os.ReadFile(filepath.Join("testdata", name))
			if err == nil {
				err = json.Unmarshal(raw, v)
			}
			if err != nil {
				t.Fatal(err)
			}
		}
		var seed delivery.Placement
		var live struct{ Users []grants.User }
		file("placement-novox-0c61bad.json", &seed)
		file("node-tools-novox-licence-subjects.json", &live)
		licence, _ := os.ReadFile(filepath.Join("testdata", "claude-licence-manager.json"))
		n := newFakeBus()
		n.manifestOf("nats", natsManifest)
		n.manifestOf("claude-licence-manager", string(licence))
		n.assign("novox", "nats")
		n.assign("novox", "claude-licence-manager")
		n.manifestOf("node-tools", `{"module":"node-tools","version":"1"}`) // the machine's tool runner, which carries the seat
		n.assign("novox", "node-tools")
		n.put(grants.ReadHave, "novox.node", map[string]any{"v": 1})
		pl, _ = delivery.EncodePlacement(seed)
		n.states[grants.ReadPlacement] = map[string][]byte{"placement.novox": pl}
		recs, _ := grants.Records(grants.ReadInputs(n, &grants.Manifests{}))
		if m := grants.Memberships(recs)["novox.claude-licence-manager"]; len(m.Membership.Seats) == 0 {
			t.Errorf("the licence manager's membership under the seeded placement carries no seats: %+v", m.Membership)
		}
		var runtime grants.User
		for _, u := range shadowOf(t, n) {
			if u.User == "novox.node-tools" {
				runtime = u
			}
		}
		for _, s := range live.Users[0].Subscribe {
			if strings.Contains(s, ".call.") && !slices.Contains(runtime.Subscribe, s) {
				t.Errorf("under the seeded placement novox.node-tools is not granted %s, which the bus grants it today", s)
			}
		}
	})

	t.Run("compare excuses a retired verb and a multiply claimed mesh seat's added subscriptions on its machines, nothing else", func(t *testing.T) {
		const retired, store, storeInfo = "mesh.seat.mesh-delivery.tool.mark-ready", "mesh.seat.mesh-store.tool.databases", "$SRV.INFO.mesh-store.>"
		two := map[string][]string{"mesh-store": {"a", "n"}}
		for _, row := range []struct {
			name                         string
			user                         string
			subShadow, subBus, pubShadow []string
			multi                        map[string][]string
			differs                      bool
			excused                      int
		}{
			{"a retired verb the shadow dropped", "a.node-tools", []string{"x"}, []string{"x", retired}, nil, nil, false, 1},
			{"a verb of a live seat the shadow lost", "a.node-tools", []string{"x"}, []string{"x", store}, nil, two, true, 0},
			{"a seat claimed on two machines, added to a user on one", "a.node-tools", []string{"x", store, storeInfo}, []string{"x"}, nil, two, false, 2},
			{"the same added to a user on a machine that does not claim it", "q.node-tools", []string{"x", store}, []string{"x"}, nil, two, true, 0},
			{"a publish of the seat added is not excused", "a.node-tools", []string{"x"}, []string{"x"}, []string{store}, two, true, 0},
			{"the same added for a seat claimed once", "a.node-tools", []string{"x", store}, []string{"x"}, nil, nil, true, 0},
		} {
			c := grants.Compare([]grants.User{{User: row.user, Subscribe: row.subShadow, Publish: row.pubShadow}}, []grants.User{{User: row.user, Subscribe: row.subBus}}, nil).
				Excusing(grants.ExcusedBy(row.multi))
			if c.Equal() == row.differs || len(c.Excused) != row.excused {
				t.Errorf("%s: equal %v, excused %v", row.name, c.Equal(), c.Excused)
			}
		}
		// The guard of the user list and the memberships (issue 1945, the lead's decision in review round 1 of its fix): a
		// seat the list in force holds left with no holder while a placed module still claims it, nothing else.
		sm, _ := catalogue.SeatNamed(catalogue.ServiceManagerSeat)
		nodeSeat := func(node string) string {
			return "mesh.seat." + sm.Name + ".tool." + sm.Serves[0].Name + "." + node
		}
		h := grants.HoldingsOf(grants.Inputs{Assigned: map[string][]string{"novox": {"postgres", "systemd"}, "ace": {"postgres", "systemd"}},
			Manifests: map[string]catalogue.Manifest{
				"postgres": {Module: "postgres", Claims: []catalogue.Claim{{Name: "mesh-store", Scope: catalogue.ScopeMesh}}},
				"systemd":  {Module: "systemd", Claims: []catalogue.Claim{{Name: sm.Name, Scope: catalogue.ScopeNode}}}}})
		u := func(user string, sub ...string) grants.User { return grants.User{User: user, Subscribe: sub} }
		for _, row := range []struct {
			name         string
			inForce, now []grants.User
			lost         []string
		}{
			{"09:21: the seat's holder lost, its claimant still placed", []grants.User{u("novox.node-tools", "x", store)}, []grants.User{u("novox.node-tools", "x")}, []string{"mesh-store"}},
			{"a dropped tool", []grants.User{u("novox.node-tools", "mesh.mod.postgres.tool.gone", store)}, []grants.User{u("novox.node-tools", store)}, nil},
			{"a seat moved from novox to ace", []grants.User{u("novox.node-tools", store)}, []grants.User{u("novox.node-tools"), u("ace.node-tools", store)}, nil},
			{"a seat no placed module claims any more", []grants.User{u("novox.node-tools", "mesh.seat.unclaimed.tool.v")}, []grants.User{u("novox.node-tools")}, nil},
			{"a retired verb dropped", []grants.User{u("novox.node-tools", retired)}, []grants.User{u("novox.node-tools")}, nil},
			{"a node seat lost on novox, held on ace", []grants.User{u("novox.node-tools", nodeSeat("novox")), u("ace.node-tools", nodeSeat("ace"))},
				[]grants.User{u("novox.node-tools"), u("ace.node-tools", nodeSeat("ace"))}, []string{sm.Name + "@novox"}},
		} {
			if lost := h.LastHolders(h.ByUsers(row.inForce), h.ByUsers(row.now)); !slices.Equal(lost, row.lost) {
				t.Errorf("%s: lost %v, want %v", row.name, lost, row.lost)
			}
		}
	})

	t.Run("tools", func(t *testing.T) {
		b := fixture()
		b.loaded = shadowOf(t, b)
		b.streams = []map[string]any{{"name": "KV_mod-x_kept", "subjects": []string{"$KV.mod-x_kept.>"}, "retention": "limits", "max_per_subject": 3}}
		p := partOn(b)
		// The bus node says its key in its have of the bus module; the process puts the sealed list (ADR 0547 clause 7).
		busKey, err := seal.GenerateKeyPair()
		if err != nil {
			t.Fatal(err)
		}
		withKey := func(w delivery.UserListWritten) {
			w.Key = busKey.PublicKey
			b.put(grants.ReadHave, "a.nats", delivery.Have{V: delivery.Version, Phase: delivery.PhaseRunning, Health: delivery.HealthOK, UserList: &w})
		}
		loadedBefore := delivery.UserListWritten{Source: "a.nats.src2", Revision: 7, Wanted: "sha256:aa", Digest: "sha256:aa", Users: 6}
		withKey(loadedBefore)
		objs := &fakeObjects{}
		p.Objects = objs
		open := func(g delivery.GrantsUserList) string {
			t.Helper()
			list, err := delivery.OpenUserList(objs.objects[g.Object], g.Digest, func(bx seal.Box) ([]byte, error) {
				out, err := seal.Open(bx, busKey.PrivateKey)
				return []byte(out), err
			})
			if err != nil {
				t.Fatalf("the sealed list does not open with the bus node's key: %v", err)
			}
			return string(list)
		}

		got, _ := p.UserList()
		if !strings.Contains(fmt.Sprint(got), "nothing composed yet") {
			t.Errorf("user-list before any composition = %v", got)
		}
		first := p.Compose()
		if !first.Written || first.Revision != 1 || !first.UserList.Compare.Equal() || first.UserList.Users != 6 {
			t.Fatalf("first composition = %+v", first)
		}
		// Written in shadow, the bus node told to follow the controller's list; every user left out while the vault holds
		// no hash; a tool's part (no object bucket) writes none.
		if g, _, had := p.Sealed(); !had || g.Follow != delivery.FollowController || g.Revision != 1 || g.Node != "a" ||
			g.Users != 0 || len(g.LeftOut) != 6 || len(objs.objects) != 1 || !strings.Contains(open(g), "accounts {") {
			t.Errorf("the sealed list in shadow = %+v, %d objects", g, len(objs.objects))
		}
		if _, _, had := partOn(fixture()).Sealed(); had {
			t.Error("a part read before any pass holds a sealed list")
		}
		if tp := partOn(fixture()); tp.Compose().Sealed == nil {
			t.Error("a tool's pass does not say the sealed list")
		} else if _, _, had := tp.Sealed(); had {
			t.Error("a tool's part wrote the sealed list")
		}
		if len(first.Published) != 3 || len(b.publishes) != 3 {
			t.Errorf("the first composition published %v, want the three assignments' memberships", first.Published)
		}
		// The second pass says each membership unchanged (published at the first); the third writes nothing at all.
		if again := p.Compose(); again.Written || again.Revision != 1 || len(again.Published) != 0 || again.AssertionsWritten != 0 {
			t.Errorf("a composition with no input changed wrote or published: %+v", again)
		}
		if third := p.Compose(); third.Written || third.MembershipsWritten != 0 || len(third.Published) != 0 || len(b.publishes) != 3 {
			t.Errorf("a membership equal to the one last published was published again, or a state written: %+v", third)
		}
		// mod-x placed on b too: b.mod-x is added and its first membership published; a.mod-x's loses the module's plain
		// subject (mod-x now runs on two machines), which leaves no seat without its holder, so it is published too (issue
		// 1945, the lead's decision in review round 1 of its fix).
		b.assign("b", "mod-x")
		moved := p.Compose()
		if !moved.Written || moved.Revision != 2 || !slices.Equal(moved.Published, []string{"a.mod-x", "b.mod-x"}) || len(moved.NotPublished) != 0 || moved.UserList.Compare.Equal() ||
			!slices.Equal(moved.UserList.Compare.Added, []string{"b.mod-x"}) {
			t.Errorf("a composition after placement moved = %+v", moved)
		}
		got, _ = p.UserList()
		ul, _ := got.(map[string]any)
		if st, ok := ul["written"].(grants.UserListState); !ok || st.Loaded == nil || st.Loaded.Digest != "sha256:aa" || st.BusNode != "a" ||
			ul["revision"] != uint64(2) || !gapNamed(st.Gaps, "people") {
			t.Errorf("user-list = %+v", got)
		}

		a, err := p.AssertOne("mod-x")
		am, _ := a.(map[string]any)
		as, _ := am["assertion"].(grants.Assertion)
		if err != nil || as.Asserted || as.Says != grants.ShadowAsserts || len(as.Items) != 3 || am["asked"] == nil {
			t.Fatalf("assert = %+v, %v", a, err)
		}
		for _, it := range as.Items {
			if it.Stream == "KV_mod-x_kept" && len(it.Differences) != 0 {
				t.Errorf("a bucket the bus holds as composed differs: %v", it.Differences)
			}
			if it.Stream == "THINGS" && !slices.Contains(it.Differences, "the bus holds no stream THINGS") {
				t.Errorf("a stream the bus lacks is not named: %+v", it)
			}
		}

		ms, _ := p.MembershipOf("a", "mod-x")
		if mo, _ := ms.(map[string]any); !strings.Contains(fmt.Sprint(mo["published"]), "last_pass") || mo["composed"] == nil {
			t.Errorf("membership = %v", ms)
		}
		gr, _ := p.Grants("mod-x")
		if g, _ := gr.(map[string]any); g["writes"] != grants.WritesNoGrant || g["count"] != 1 {
			t.Errorf("grants = %v", gr)
		}

		b.loaded = append(b.loaded, grants.User{User: "b.gone"})
		fa := &fakeAsker{wheres: map[string]*asks.Warrant{}}
		var forgot []string
		n := 0
		p.Nonce, p.Forget = func() string { n++; return fmt.Sprintf("%04d", n) }, func(id string) error { forgot = append(forgot, id); return nil }
		var said []asks.Condition
		p.Asker, p.Say = fa, func(c asks.Condition) error { said = append(said, c); return nil }
		warrant := func(id string) asks.Warrant { return asks.Warrant{Ask: id, Outcome: asks.OutcomeChosen} }
		last := func() grants.Act {
			raw, _, _, _ := b.ownGet(grants.StateTakeover, grants.KeySwitch)
			var s grants.Switch
			_ = json.Unmarshal(raw, &s)
			if s.Open != "" && s.Acts[len(s.Acts)-1].Said != "asked" {
				t.Errorf("an ask is open and its act is not asked: %+v", s)
			}
			return s.Acts[len(s.Acts)-1]
		}
		asked := func(act string) string {
			t.Helper()
			var res struct{ Asked string }
			var err error
			var out any
			if act == "take-over" {
				out, err = p.TakeOver("shanks.node-tools", "a row")
			} else {
				out, err = p.HandBack("shanks.node-tools", "a row")
			}
			if err != nil {
				t.Fatalf("%s: %v", act, err)
			}
			raw, _ := json.Marshal(out)
			_ = json.Unmarshal(raw, &res)
			return res.Asked
		}
		yes, no := asks.Option{ID: "yes"}, asks.Option{ID: "no"}
		for _, row := range []struct {
			name, act   string
			option      asks.Option
			setup       func()
			said, never []string // the refusal's words and the users it must not name
			state       string
			outcome     string
		}{
			{"a yes while a user differs is refused and said, naming it", "take-over", yes, func() {}, []string{"users differ", "b.mod-x"}, []string{"b.gone"}, grants.Shadow, "refused"},
			{"a no leaves the switch", "take-over", no, func() {}, nil, nil, grants.Shadow, "declined"},
			{"a yes with the lists agreeing and every hash held records the switch", "take-over", yes, func() {
				b.states[grants.ReadAssignments] = nil
				b.assign("a", "nats")
				b.assign("a", "mod-x")
				b.assign("b", "mod-y")
				b.loaded = append(shadowOf(t, b), grants.User{User: "b.gone"})
				for _, u := range shadowOf(t, b) {
					b.put(grants.ReadAccounts, u.User, map[string]any{"user": u.User, "hash": "$2a$10$x", "generation": 1})
				}
			}, nil, nil, grants.TookOver, "recorded"},
			{"a yes to hand back records the switch back", "hand-back", yes, func() {}, nil, nil, grants.Shadow, "recorded"},
		} {
			t.Run(row.name, func(t *testing.T) {
				row.setup()
				before := len(fa.asks)
				id := asked(row.act)
				if _, err := p.TakeOver("shanks.node-tools", "again"); err == nil || !strings.Contains(err.Error(), "already asked") {
					t.Errorf("a second ask while one is open = %v", err)
				}
				p.Compose()
				p.Compose()
				if len(fa.asks) != before+1 || fa.asks[before].ID != id {
					t.Fatalf("the operator was asked %d times, want once: %+v", len(fa.asks)-before, fa.asks)
				}
				ask := fa.asks[before]
				if err := ask.Check(time.Date(2026, 10, 25, 22, 0, 0, 0, time.UTC)); err != nil {
					t.Errorf("the router would refuse the ask: %v", err)
				}
				if yesOpt, ok := ask.Option("yes"); !ok || yesOpt.Level != asks.Approve || !strings.HasPrefix(yesOpt.Binds, "sha256:") {
					t.Errorf("the yes does not approve and bind its act: %+v", yesOpt)
				}
				said = nil
				if err := p.Warranted(row.option, warrant(id)); err != nil {
					t.Fatal(err)
				}
				l := last()
				if l.Said != row.outcome || l.Ask != id || p.SwitchState() != row.state {
					t.Errorf("the act = %+v, the switch %s; want %s and %s", l, p.SwitchState(), row.outcome, row.state)
				}
				for _, w := range row.said {
					if !strings.Contains(l.Refused, w) || (row.outcome == "refused" && (len(said) != 1 || !strings.Contains(said[0].Explanation, w))) {
						t.Errorf("the refusal %q (said %v) does not say %q", l.Refused, said, w)
					}
				}
				for _, w := range row.never {
					if strings.Contains(l.Refused, w) {
						t.Errorf("the refusal names %q", w)
					}
				}
				// A recorded switch says no refusal and clears the one a refused yes left raised.
				if row.outcome == "recorded" && row.act == "take-over" && (len(said) != 1 || said[0].State != asks.StateCleared || said[0].Key != "mesh-grants.take-over-refused") {
					t.Errorf("a recorded switch did not clear the refusal: %v", said)
				}
				if row.outcome == "recorded" && !strings.Contains(fmt.Sprint(p.TakeOverState()), "bus_node_loaded_grants_list:not yet") {
					t.Errorf("the state claims the bus node follows with no loaded list: %v", fmt.Sprint(p.TakeOverState()))
				}
				// The key the bus node follows turns with the switch at once, and the state says switched only once the bus
				// node loaded the grants part's written list.
				g, _, _ := p.Sealed()
				if want := map[string]string{grants.TookOver: delivery.FollowGrants, grants.Shadow: delivery.FollowController}[p.SwitchState()]; g.Follow != want {
					t.Errorf("the key says follow %s with the switch %s", g.Follow, p.SwitchState())
				}
				effect := func() string { st, _ := p.TakeOverState(); return fmt.Sprint(st.(map[string]any)["effect"]) }
				if row.outcome == "recorded" && row.act == "take-over" {
					if e := effect(); strings.HasPrefix(e, "switched") || !strings.Contains(e, "not in effect") {
						t.Errorf("effect before the bus node loaded = %s", e)
					}
					if users := strings.Count(open(g), "{ user: "); users != g.Users || g.Users == 0 || len(g.LeftOut) != 0 {
						t.Errorf("the sealed list holds %d users, the key says %d, left out %v", users, g.Users, g.LeftOut)
					}
					withKey(delivery.UserListWritten{Source: delivery.GrantsUserListSource, Revision: g.Revision, Wanted: g.Digest, Digest: g.Digest, Users: g.Users, Follows: delivery.FollowGrants})
					if e := effect(); !strings.HasPrefix(e, "switched") {
						t.Errorf("effect once the bus node loaded the written list = %s", e)
					}
					withKey(loadedBefore)
					// After take-over a list composed past a failed read, or one dropping a user of the list in force for
					// want of a hash, is not sealed: the list in force stays, and the pass says why.
					b.refused[grants.ReadAccounts] = true
					if res := p.Compose(); res.Sealed == nil || !strings.Contains(res.Sealed.Why, "a read of this pass failed") {
						t.Errorf("a pass past a failed read = %+v", res.Sealed)
					}
					// While the hold lasts the warning stands, said once however many passes find it; it names why.
					p.Compose()
					nHeld := 0
					for _, c := range said {
						if c.Key == grants.HeldCondition && c.State == asks.StateRaised && c.Severity == asks.SeverityWarning && strings.Contains(c.Summary, "a read of this pass failed") {
							nHeld++
						}
					}
					if nHeld != 1 {
						t.Errorf("the held list raised the warning %d times, want once: %+v", nHeld, said)
					}
					b.refused[grants.ReadAccounts] = false
					if now, _, _ := p.Sealed(); now.Digest != g.Digest || now.Object != g.Object {
						t.Errorf("the list in force moved past a failed read: %s, was %s", now.Digest, g.Digest)
					}
					b.mu.Lock()
					hash := b.states[grants.ReadAccounts]["a.mod-x"]
					delete(b.states[grants.ReadAccounts], "a.mod-x")
					b.mu.Unlock()
					if res := p.Compose(); res.Sealed == nil || !strings.Contains(res.Sealed.Why, "a.mod-x would be left out") {
						t.Errorf("a pass that drops a.mod-x's hash = %+v", res.Sealed)
					}
					if now, _, _ := p.Sealed(); now.Digest != g.Digest {
						t.Errorf("the list in force moved without a.mod-x: %s", now.Digest)
					}
					// A list in force written before the part kept its users (no sealed-users): checked against the users the
					// bus loaded, so the first list after take-over has the same protection.
					b.mu.Lock()
					delete(b.own[grants.StateUserList], grants.KeyWrittenUsers)
					b.mu.Unlock()
					if res := p.Compose(); res.Sealed == nil || !strings.Contains(res.Sealed.Why, "a.mod-x would be left out") {
						t.Errorf("a pass with no kept users that drops a.mod-x's hash = %+v", res.Sealed)
					}
					if now, _, _ := p.Sealed(); now.Digest != g.Digest {
						t.Errorf("the list in force moved without a.mod-x and no kept users: %s", now.Digest)
					}
					b.put(grants.ReadAccounts, "a.mod-x", json.RawMessage(hash))
					if p.Compose(); func() bool { now, _, _ := p.Sealed(); return now.Digest != g.Digest }() {
						t.Errorf("the list in force moved with every read and hash back")
					}
					if last := said[len(said)-1]; last.Key != grants.HeldCondition || last.State != asks.StateCleared {
						t.Errorf("the held warning is not cleared once nothing is held: %+v", last)
					}
					// A part started while the warning stood (the said state is in memory only) clears it on its first pass.
					var fresh []asks.Condition
					fp := partOn(b)
					fp.Objects = p.Objects
					fp.Asker, fp.Say = fa, func(c asks.Condition) error { fresh = append(fresh, c); return nil }
					fp.Compose()
					if len(fresh) == 0 || fresh[0].Key != grants.HeldCondition || fresh[0].State != asks.StateCleared {
						t.Errorf("a fresh part's first pass does not say the held warning is cleared: %+v", fresh)
					}
					// Issue 1945, 2026-10-27 09:21: a list that would leave a seat the list in force holds with no holder,
					// while a placed module still claims it, is held, as such a membership is: not written, the warning
					// raised naming the seat. A list that only adds is written; one whose loaded grants cannot be read is held.
					inForce := slices.Clone(b.loaded)
					seat, verb := brokerSeat()
					seatGrant := "mesh.seat." + seat + ".call." + verb + ".*"
					for i := range b.loaded {
						if b.loaded[i].User == "a.nats" {
							b.loaded[i].Subscribe = append(slices.Clone(b.loaded[i].Subscribe), seatGrant)
						}
					}
					b.put(grants.ReadAssignments, "a.mod-y", map[string]any{"node": "a", "module": "mod-y", "assigned": "2026-10-27T08:20:00Z"})
					b.put(grants.ReadAccounts, "a.mod-y", map[string]any{"user": "a.mod-y", "hash": "$2a$10$x", "generation": 1})
					said = nil
					res := p.Compose()
					if res.Sealed == nil || !strings.Contains(res.Sealed.Why, "publishing would lose the last holder of "+seat) {
						t.Errorf("a list losing a seat grant = %+v", res.Sealed)
					}
					if now, _, _ := p.Sealed(); now.Digest != g.Digest {
						t.Errorf("a list losing a seat grant was written: %s, was %s", now.Digest, g.Digest)
					}
					if len(said) != 1 || said[0].Key != grants.HeldCondition || said[0].State != asks.StateRaised || !strings.Contains(said[0].Summary, "the last holder of "+seat) {
						t.Errorf("the held list did not raise the warning naming the lost grant: %+v", said)
					}
					b.loaded = inForce
					if p.Compose(); func() bool { now, _, _ := p.Sealed(); return now.Digest == g.Digest }() {
						t.Errorf("a list that only adds a.mod-y was not written")
					}
					written, _, _ := p.Sealed()
					b.mu.Lock()
					b.refuseUsers = true
					b.mu.Unlock()
					b.mu.Lock()
					delete(b.states[grants.ReadAssignments], "a.mod-y")
					b.mu.Unlock()
					if res := p.Compose(); res.Sealed == nil || !strings.Contains(res.Sealed.Why, "the grants of the list in force cannot be read") {
						t.Errorf("a pass whose loaded list cannot be read = %+v", res.Sealed)
					}
					if now, _, _ := p.Sealed(); now.Digest != written.Digest {
						t.Errorf("a list was written while the loaded list could not be read")
					}
					b.mu.Lock()
					b.refuseUsers = false
					b.mu.Unlock()
				}
			})
		}
		t.Run("hand-back in shadow is refused at once, with nothing asked", func(t *testing.T) {
			n := len(fa.asks)
			if _, err := p.HandBack("shanks.node-tools", "a row"); err == nil || !strings.Contains(err.Error(), "nothing to hand back") {
				t.Errorf("hand-back in shadow = %v", err)
			}
			p.Compose()
			if len(fa.asks) != n {
				t.Errorf("a refused hand-back asked the operator")
			}
		})
		t.Run("an ask that can stay open is closed every way and can be asked again", func(t *testing.T) {
			// A warrant the process missed is caught up from the router's record, whatever its outcome.
			id := asked("take-over")
			p.Compose()
			fa.wheres[id] = &asks.Warrant{Ask: id, Outcome: asks.OutcomeChosen, Option: "no"}
			p.Compose()
			if l := last(); l.Ask != id || l.Said != "declined" {
				t.Errorf("a missed warrant was not caught up: %+v", l)
			}
			// The router ended it with no choice, and the process was not told.
			id = asked("take-over")
			p.Compose()
			fa.wheres[id] = &asks.Warrant{Ask: id, Outcome: asks.OutcomeCancelled}
			p.Compose()
			if l := last(); l.Ask != id || !strings.Contains(l.Said, "cancelled") {
				t.Errorf("an ask the router ended was not closed: %+v", l)
			}
			// Said closes on any outcome for the open id, and none for another id.
			id = asked("take-over")
			p.Said(asker.Refused, asks.Warrant{Ask: "other", Outcome: asks.OutcomeRefused}, nil)
			if _, err := p.TakeOver("x", "y"); err == nil {
				t.Errorf("a warrant for another ask closed the open one")
			}
			p.Said(asker.Refused, asks.Warrant{Ask: id, Outcome: asks.OutcomeRefused}, nil)
			// A warrant for an ask that is not the open one switches nothing.
			if err := p.Warranted(yes, warrant("take-over-other")); err == nil {
				t.Errorf("a warrant for an ask that is not open was acted on")
			}
			// Past its expiry and a margin the part closes it itself; the clock moves, not a timer.
			id = asked("take-over")
			now := p.Now
			p.Now = func() time.Time { return now().Add(25 * time.Hour) }
			p.Compose()
			p.Now = now
			if l := last(); l.Ask != id || l.Said != string(asks.OutcomeExpired) {
				t.Errorf("an expired ask was not closed: %+v", l)
			}
			// An ask that could not be published is closed as refused, its half-made record taken away, and is not retried.
			fa.fail = true
			id = asked("take-over")
			p.Compose()
			p.Compose()
			if l := last(); l.Ask != id || l.Said != "refused" || !slices.Contains(forgot, id) || !slices.Contains(fa.cancels, id) {
				t.Errorf("a failed ask stays open, or is not taken back at the router: %+v, forgot %v, cancelled %v", l, forgot, fa.cancels)
			}
			fa.fail = false
			// An answer the part's own record cannot take yet (its state out of reach) leaves the ask open, closed by
			// nothing, and is taken at a later pass.
			id = asked("take-over")
			p.Compose()
			fa.wheres[id] = &asks.Warrant{Ask: id, Outcome: asks.OutcomeChosen, Option: "no"}
			fa.takeErr = errors.New("nats: no responders available for request")
			p.Compose()
			if l := last(); l.Ask != id || l.Said != "asked" {
				t.Errorf("an answer not taken closed the ask: %+v", l)
			}
			fa.takeErr = nil
			p.Compose()
			if l := last(); l.Ask != id || l.Said != "declined" {
				t.Errorf("the answer was not taken once its record could be reached: %+v", l)
			}
			asked("take-over")
		})

		t.Run("only memberships published, nothing asserted", func(t *testing.T) {
			for _, s := range b.publishes {
				if !strings.HasPrefix(s, "mesh.assignment.") {
					t.Errorf("published on %s", s)
				}
			}
			for _, w := range b.writes {
				if !slices.Contains(grants.States, w) {
					t.Errorf("wrote %s, which is not the part's own state", w)
				}
			}
			for _, c := range b.calls {
				if c != grants.CallUsers && c != grants.CallStreams {
					t.Errorf("called %s: the part calls only the bus module's read tools", c)
				}
			}
			for _, e := range b.events {
				if !slices.Contains(grants.Emits, e) {
					t.Errorf("said %s", e)
				}
			}
		})
	})

	t.Run("memberships: published unless a seat would lose its last holder or a holder a capability it asks for", func(t *testing.T) {
		const key = "a.mod-x"
		brokerName, brokerVerb := brokerSeat()
		// The telegram module's claim of its channel, as mesh-catalog's telegram manifest has it (c05aa5e6), on mod-x.
		const telegramClaim = `[{"name":"channel","scope":"mesh","kind":"telegram","capabilities":["deliver","verified-sender"]}]`
		verified := func(m map[string]any) map[string]any {
			m["seat-traffic"] = map[string]any{"kinds": []any{map[string]any{"seat": "channel", "kind": "telegram", "module": "mod-x", "node": "a",
				"capabilities": []any{"deliver", "verified-sender"}}}}
			return m
		}
		composed := func(b *fakeBus) map[string]any {
			recs, _ := grants.Records(grants.ReadInputs(b, &grants.Manifests{}))
			raw, _ := json.Marshal(grants.Memberships(recs)[key].Membership)
			var m map[string]any
			_ = json.Unmarshal(raw, &m)
			return m
		}
		for _, row := range []struct {
			name      string
			last      func(map[string]any) map[string]any
			published bool
			names     string
			// claims, when set, are mod-x's claims in its manifest for the row.
			claims string
		}{
			{"a first membership is published", nil, true, "", ""},
			{"an additive change is published, the private network carried", func(m map[string]any) map[string]any {
				delete(m, "state")
				m["mesh"] = []any{"10.0.0.1"}
				return m
			}, true, "", ""},
			// The lead's decision in review round 1 of the fix of issue 1945: only a seat left with no holder, or a
			// capability its holder still asks for (verified-sender, dropped by a root-free word that failed), holds a
			// membership back; a dropped tool or field is published.
			{"a change that drops a tool is published", func(m map[string]any) map[string]any {
				m["serves"] = append(m["serves"].([]any), map[string]any{"subject": "mesh.mod.mod-x.tool.gone"})
				m["mesh"] = []any{"10.0.0.1"}
				return m
			}, true, "", ""},
			{"a change that drops verified-sender its holder still asks for is not published, and named", verified, false, "channel telegram verified-sender of a/mod-x", telegramClaim},
			{"a change that drops verified-sender its holder no longer asks for is published", verified, true, `"published":"published"`, `[{"name":"channel","scope":"mesh","kind":"telegram"}]`},
			{"a change that takes the last holder from a seat a placed module claims is not published, the seat named", func(m map[string]any) map[string]any {
				m["seats"] = []any{map[string]any{"seat": brokerName, "verb": brokerVerb, "subject": "mesh.seat." + brokerName + ".tool." + brokerVerb}}
				return m
			}, false, "the last holder of " + brokerName, ""},
			// A verb the seat catalogue retired on purpose (mark-ready, mesh-sdk d506f21, ADR 0421) is dropped and named; a
			// verb of a seat the catalogue does not define is still a loss (issue 1945).
			{"a change that drops only a retired seat verb is published, the verb named", func(m map[string]any) map[string]any {
				m["seats"] = []any{map[string]any{"seat": "mesh-delivery", "verb": "mark-ready", "subject": "mesh.seat.mesh-delivery.tool.mark-ready"}}
				return m
			}, true, "mesh-delivery mark-ready", ""},
			{"a seat no placed module claims dropped is published", func(m map[string]any) map[string]any {
				m["seats"] = []any{map[string]any{"seat": "mesh-delivery", "verb": "mark-ready", "subject": "mesh.seat.mesh-delivery.tool.mark-ready"},
					map[string]any{"seat": "telegram-sender", "verb": "send", "subject": "mesh.seat.telegram-sender.tool.send"}}
				return m
			}, true, "mesh-delivery mark-ready", ""},
		} {
			t.Run(row.name, func(t *testing.T) {
				b := fixture()
				if row.claims != "" {
					b.manifestOf("mod-x", strings.Replace(xManifest, `"own-secrets"`, `"claims":`+row.claims+`,"own-secrets"`, 1))
				}
				b.loaded = shadowOf(t, b)
				if row.last != nil {
					raw, _ := json.Marshal(row.last(composed(b)))
					b.stream = map[string][]byte{"mesh.assignment." + key: raw}
					b.seqs = map[string]uint64{"mesh.assignment." + key: 4}
				}
				res := partOn(b).Compose()
				if got := slices.Contains(res.Published, key); got != row.published {
					t.Fatalf("published %v, not published %v", res.Published, res.NotPublished)
				}
				if row.published {
					if row.names == "" && row.last != nil && !strings.Contains(string(b.stream["mesh.assignment."+key]), "10.0.0.1") {
						t.Errorf("the private network of the last membership is not carried: %s", b.stream["mesh.assignment."+key])
					}
					if raw, _, _, _ := b.ownGet(grants.StateMemberships, key); !strings.Contains(string(raw), row.names) {
						t.Errorf("the pass does not name %q: %s", row.names, raw)
					}
					return
				}
				said := strings.Join(res.NotPublished, "\n")
				if !strings.Contains(said, grants.ShadowDifference) || !strings.Contains(said, row.names) {
					t.Errorf("the loss is not named: %s", said)
				}
				ms, _ := partOn(b).MembershipOf("a", "mod-x")
				if !strings.Contains(fmt.Sprint(ms), row.names) {
					t.Errorf("grants_membership does not name what would be lost: %v", ms)
				}
			})
		}
		t.Run("a refused publish: no exit, said, published at the next event", func(t *testing.T) {
			b := fixture()
			b.loaded = shadowOf(t, b)
			b.refusePub = true
			p := partOn(b)
			refused := p.Compose()
			if len(refused.Published) != 0 || len(refused.NotPublished) != 3 || !strings.Contains(refused.NotPublished[0], "Permissions Violation") {
				t.Errorf("a refused publish = %+v: said, and nothing published", refused)
			}
			b.refusePub = false
			if next := p.Compose(); !slices.Equal(next.Published, []string{"a.mod-x", "a.nats", "b.mod-y"}) {
				t.Errorf("the next event published %v", next.Published)
			}
		})
		t.Run("a tool answers while a pass waits on the bus", func(t *testing.T) {
			b := fixture()
			b.loaded = shadowOf(t, b)
			b.hold = make(chan struct{})
			p := partOn(b)
			done := make(chan struct{})
			go func() { p.Compose(); close(done) }()
			answered := make(chan struct{})
			go func() {
				_, _ = p.UserList()
				_, _ = p.MembershipOf("a", "mod-x")
				_, _ = p.Grants("")
				_ = p.Last()
				close(answered)
			}()
			select {
			case <-answered:
			case <-time.After(10 * time.Second):
				t.Error("a tool waited on the pass's round trip")
			}
			close(b.hold)
			<-done
		})
	})

	t.Run("assertions: what the bus lacks is created once, what it holds is never touched", func(t *testing.T) {
		b := fixture()
		b.loaded = shadowOf(t, b)
		// The bus holds mod-x's bucket with another history, and neither its log nor its stream.
		b.streams = []map[string]any{{"name": "KV_mod-x_kept", "subjects": []string{"$KV.mod-x_kept.>"}, "retention": "limits", "max_per_subject": 2}}
		p := partOn(b)
		p.Create = b
		assertion := func() grants.Assertion {
			raw, _, _, _ := b.ownGet(grants.StateAssertions, "mod-x")
			var a grants.Assertion
			_ = json.Unmarshal(raw, &a)
			return a
		}
		first := p.Compose()
		if !slices.Equal(b.creates, []string{"LOG_mod-x_history", "THINGS"}) || len(first.Asserted) != 1 ||
			!strings.HasPrefix(first.Asserted[0], "mod-x at ") || !slices.Contains(b.events, grants.EventAsserted) {
			t.Fatalf("the first pass created %v, said %v, events %v", b.creates, first.Asserted, b.events)
		}
		a := assertion()
		if !a.Asserted || a.Says != grants.CreatesMissing {
			t.Errorf("the assertion kept = %+v", a)
		}
		for _, it := range a.Items {
			switch it.Stream {
			case "KV_mod-x_kept":
				if it.Created != "" || !slices.Contains(it.Differences, "history 2 held, 3 composed") {
					t.Errorf("a bucket the bus holds was touched, or its difference not said: %+v", it)
				}
			default:
				if it.Created != grants.ItemCreated {
					t.Errorf("%s: %q, want created", it.Stream, it.Created)
				}
			}
		}
		if again := p.Compose(); len(again.Asserted) != 0 || len(b.creates) != 2 {
			t.Errorf("a pass with everything held created again: %v, %v", again.Asserted, b.creates)
		}
		// THINGS deleted since: not made again at the same manifest, said; a hand assert (the tool, asking the process)
		// makes it again.
		b.mu.Lock()
		b.streams = slices.DeleteFunc(b.streams, func(s map[string]any) bool { return s["name"] == "THINGS" })
		b.mu.Unlock()
		gone := p.Compose()
		if len(b.creates) != 2 || !strings.Contains(strings.Join(gone.NotAsserted, " "), "THINGS: created at this manifest and gone since") {
			t.Errorf("a stream gone since was made again by itself, or not said: %v, %v", b.creates, gone.NotAsserted)
		}
		tool := partOn(b)
		if got, err := tool.AssertOne("mod-x"); err != nil || fmt.Sprint(got) == "" || len(b.creates) != 2 {
			t.Fatalf("the tool = %v, %v, creates %v: it asks, and creates nothing itself", got, err, b.creates)
		}
		if hand := p.Compose(); len(hand.Asserted) != 1 || b.creates[len(b.creates)-1] != "THINGS" {
			t.Errorf("the hand assert did not create THINGS again: %v, %v", hand.Asserted, b.creates)
		}
		if after := p.Compose(); len(after.Asserted) != 0 {
			t.Errorf("the hand ask was acted on twice: %v", after.Asserted)
		}
		for _, c := range b.creates {
			if c == "KV_mod-x_kept" {
				t.Error("the bucket the bus holds was asked to be created")
			}
		}
	})

	t.Run("assertions: a refused create is said, never stops it, and is tried at the next event", func(t *testing.T) {
		b := fixture()
		b.loaded = shadowOf(t, b)
		b.refuseCreate = true
		p := partOn(b)
		p.Create = b
		refused := p.Compose()
		if len(refused.Asserted) != 0 || !strings.Contains(strings.Join(refused.NotAsserted, " "), "Permissions Violation") ||
			slices.Contains(b.events, grants.EventAsserted) {
			t.Fatalf("a refused create = %+v", refused)
		}
		b.refuseCreate = false
		if next := p.Compose(); len(next.Asserted) != 1 || !strings.Contains(next.Asserted[0], "KV_mod-x_kept") {
			t.Errorf("the next event created %v", next.Asserted)
		}
		// What the bus holds unread: nothing is created.
		c := fixture()
		c.loaded = shadowOf(t, c)
		q := partOn(c)
		q.Create = c
		q.Call = refusingStreams{c}
		if r := q.Compose(); len(c.creates) != 0 || len(r.Asserted) != 0 {
			t.Errorf("created %v with what the bus holds unread", c.creates)
		}
	})

	t.Run("memberships held back: every one is said and listed", func(t *testing.T) {
		b := fixture()
		b.loaded = shadowOf(t, b)
		recs, _ := grants.Records(grants.ReadInputs(b, &grants.Manifests{}))
		b.stream, b.seqs = map[string][]byte{}, map[string]uint64{}
		for i, key := range []string{"a.mod-x", "b.mod-y"} {
			raw, _ := json.Marshal(grants.Memberships(recs)[key].Membership)
			var m map[string]any
			_ = json.Unmarshal(raw, &m)
			seat, verb := brokerSeat()
			m["seats"] = []any{map[string]any{"seat": seat, "verb": verb, "subject": "mesh.seat." + seat + ".tool." + verb}}
			raw, _ = json.Marshal(m)
			subject := "mesh.assignment." + key
			b.stream[subject], b.seqs[subject] = raw, uint64(i+1)
		}
		var logged []string
		var lmu sync.Mutex
		w := &fakeWatcher{opened: make(chan string, 16)}
		f := &grants.Follower{Part: partOn(b), Watch: w, Logf: func(format string, args ...any) {
			lmu.Lock()
			logged = append(logged, fmt.Sprintf(format, args...))
			lmu.Unlock()
		}}
		ctx, cancel := context.WithCancel(context.Background())
		done := make(chan struct{})
		go func() { f.Run(ctx); close(done) }()
		waitFor(t, func() bool {
			lmu.Lock()
			defer lmu.Unlock()
			all := strings.Join(logged, "\n")
			return strings.Contains(all, "held a.mod-x: ") && strings.Contains(all, "held b.mod-y: ")
		})
		cancel()
		<-done
		held, err := partOn(b).MembershipOf("", "")
		h, _ := held.(map[string]any)
		if seat, _ := brokerSeat(); err != nil || h["count"] != 2 || !strings.Contains(fmt.Sprint(h["held"]), "the last holder of "+seat) {
			t.Errorf("grants_membership with neither node nor module = %v, %v", held, err)
		}
		if _, err := partOn(b).MembershipOf("a", ""); err == nil {
			t.Error("a node without a module was answered")
		}
	})

	t.Run("a refused read or write never stops it", func(t *testing.T) {
		b := fixture()
		b.loaded = shadowOf(t, b)
		b.refuseTo[grants.StateMemberships] = true
		res := partOn(b).Compose()
		if !res.Written || len(res.Errors) == 0 || !strings.Contains(strings.Join(res.Errors, " "), "memberships") {
			t.Errorf("a refused write of memberships = %+v: the user list is written all the same, the refusal said", res)
		}
		w := &fakeWatcher{refuse: map[string]int{grants.ReadModules: 1}, opened: make(chan string, 16)}
		var logged []string
		var lmu sync.Mutex
		f := &grants.Follower{Part: partOn(b), Watch: w, Logf: func(format string, args ...any) {
			lmu.Lock()
			logged = append(logged, fmt.Sprintf(format, args...))
			lmu.Unlock()
		}}
		ctx, cancel := context.WithCancel(context.Background())
		done := make(chan struct{})
		go func() { f.Run(ctx); close(done) }()
		waitOpened(t, w, grants.ReadAssignments)
		if r := f.Refused(); r[grants.ReadModules] == "" {
			waitFor(t, func() bool { return f.Refused()[grants.ReadModules] != "" })
		}
		w.change(grants.ReadAssignments, "a.mod-x")
		waitOpened(t, w, grants.ReadModules)
		waitFor(t, func() bool { return len(f.Refused()) == 0 })
		select {
		case <-done:
			t.Fatal("the follower stopped")
		default:
		}
		cancel()
		<-done
		lmu.Lock()
		defer lmu.Unlock()
		if !strings.Contains(strings.Join(logged, "\n"), "cannot be watched yet") {
			t.Errorf("the refusal was not said: %v", logged)
		}
	})

	// 774/AC4 (novox/hq ADR 0561 §2): every account the vault mints that the records compose is written to the state
	// accounts once, with the bus's address and a module's claims, read by the vault alone; a key is deleted when placement
	// no longer names its user, and never in a pass whose reads failed.
	t.Run("wanted accounts: written once each, read by the vault alone, retired only when placement drops them", func(t *testing.T) {
		b := fixture()
		b.loaded = shadowOf(t, b)
		p := partOn(b)
		p.Bus = grants.BusAddress{URL: "nats://a.mesh:4222", Fingerprint: "ab"}
		p.Compose()
		p.Compose()
		wrote := 0
		for _, w := range b.writes {
			if w == grants.StateAccounts {
				wrote++
			}
		}
		held := slices.Sorted(maps.Keys(b.own[grants.StateAccounts]))
		if !slices.Equal(held, []string{"a.mod-x", "a.nats", "b.mod-y"}) || wrote != 3 {
			t.Fatalf("accounts %v written %d times in two passes, want the three modules' once each", held, wrote)
		}
		nats, err := buscompose.ReadWantedAccount("a.nats", b.own[grants.StateAccounts]["a.nats"])
		if err != nil || nats.URL != "nats://a.mesh:4222" || nats.Fingerprint != "ab" || len(nats.Claims) != 1 ||
			nats.Claims[0].Seat != catalogue.BrokerSeat || nats.At.IsZero() {
			t.Errorf("a.nats is wanted as %+v (%v)", nats, err)
		}
		var readers []string
		for _, s := range grants.Announced() {
			if s.Name == grants.StateAccounts {
				if s.Readable {
					t.Error("the wanted accounts are announced readable by anyone")
				}
				readers = s.Readers
			}
		}
		if !slices.Equal(readers, []string{"mesh-vault"}) || buscompose.ReaderMay("mesh-delivery-view", buscompose.GrantsAccounts) {
			t.Errorf("the wanted accounts are read by %v", readers)
		}
		// A read that fails retires nothing; once read, the user placement dropped is retired.
		delete(b.states[grants.ReadAssignments], "b.mod-y")
		b.refused[grants.ReadResolved] = true
		if res := p.Compose(); res.Accounts == nil || len(res.Accounts.Deleted) != 0 || b.own[grants.StateAccounts]["b.mod-y"] == nil {
			t.Fatalf("a pass whose read failed deleted %+v", res.Accounts)
		}
		delete(b.refused, grants.ReadResolved)
		if res := p.Compose(); res.Accounts == nil || !slices.Equal(res.Accounts.Deleted, []string{"b.mod-y"}) {
			t.Fatalf("the user placement dropped is not retired: %+v", res.Accounts)
		}
		// The tool reads them, one and all, each with when it was written.
		one, err := p.Accounts("a.nats")
		all, err2 := p.Accounts("")
		if err != nil || err2 != nil || one.(map[string]any)["count"] != 1 || all.(map[string]any)["count"] != 2 ||
			one.(map[string]any)["accounts"].([]buscompose.WantedAccount)[0].At.IsZero() {
			t.Errorf("the tool reads %v and %v (%v %v)", one, all, err, err2)
		}
		if _, err := p.Accounts("b.mod-y"); err == nil {
			t.Error("the tool reads an account no longer wanted")
		}
		p.Pass()
		if all, _ := p.Accounts(""); all.(map[string]any)["consumers"] == nil {
			t.Errorf("the tool does not say the account consumers in shadow: %v", all)
		}
		// With no bus address no account is written, and the pass says why.
		bare := partOn(fixture())
		if res := bare.Compose(); res.Accounts != nil || !strings.Contains(strings.Join(res.Errors, " "), "no bus address") {
			t.Errorf("a part with no bus address wrote %+v: %v", res.Accounts, res.Errors)
		}
	})

	// 774/AC5 (novox/hq ADR 0561 §1): the vault's account-issued wakes a pass, so the next list carries the new user's hash
	// within one pass; an event of another kind does not.
	t.Run("the vault's account-issued composes the list again", func(t *testing.T) {
		b := fixture()
		var handle func(string, []byte)
		p := partOn(b)
		f := &grants.Follower{Part: p, Watch: &fakeWatcher{opened: make(chan string, 16)}, Logf: func(string, ...any) {},
			Hear: func(h func(string, []byte)) error { handle = h; return nil }}
		ctx, cancel := context.WithCancel(context.Background())
		done := make(chan struct{})
		go func() { f.Run(ctx); close(done) }()
		defer func() { cancel(); <-done }()
		waitFor(t, func() bool { return b.count(grants.CallUsers) > 0 && handle != nil })
		held := func() bool {
			for _, c := range p.Last().UserList.Credentials.Users {
				if c.User == "a.mod-x" {
					return c.HashHeld
				}
			}
			return false
		}
		if held() {
			t.Fatal("a.mod-x has a hash before the vault made one")
		}
		b.mu.Lock()
		b.states[grants.ReadAccounts] = map[string][]byte{"a.mod-x": []byte(`{"user":"a.mod-x","hash":"$2a$10$x","generation":1}`)}
		b.mu.Unlock()
		handle(buscompose.AccountIssuedSubject, []byte(`{"user":"a.mod-x","kind":"module","node":"a","module":"mod-x","generation":1}`))
		waitFor(t, held)
		if !slices.Contains(grants.Consumes, grants.EventAccountIssued) || !grants.IsAccountIssued(grants.EventAccountIssued) ||
			grants.IsAccountIssued("mesh.mod.mesh-vault.event.secret-changed") {
			t.Errorf("the part hears %v", grants.Consumes)
		}
	})

	// 774/AC6 (novox/hq ADR 0561 §6): the durable consumers an account needs, with the controller's configuration, are
	// compared in shadow while the controller holds the lease, and created, only where the bus lacks them, from the write
	// that hands the lease away; one the bus holds is never changed.
	t.Run("account consumers: compared while the controller holds the lease, created once it is handed away", func(t *testing.T) {
		const cManifest = `{"module":"mod-c","version":"1","own-secrets":{"broker":"/var/lib/c/broker"},"consumes":["mod-y.done"]}`
		b := fixture()
		b.manifestOf("mod-c", cManifest)
		b.assign("b", "mod-c")
		b.loaded = shadowOf(t, b)
		b.put(grants.ReadLease, grants.LeaseKey, map[string]any{"instance": "novox/1/2026-10-27", "epoch": 57})
		p := partOn(b)
		p.Consumers = b
		res := p.Compose()
		if res.Consumers == nil || res.Consumers.On || !slices.Contains(res.Consumers.Missing, "EVENTS.b_mod-c") || len(b.consumerCreates) != 0 {
			t.Fatalf("while the controller holds the lease: %+v, created %v", res.Consumers, b.consumerCreates)
		}
		b.put(grants.ReadLease, grants.LeaseKey, map[string]any{"handed-to": "the operator's hand-over"})
		b.consumers = map[string][]map[string]any{"EVENTS": {{"name": "b_other", "filters": []string{"x"}, "max_deliver": 5}}}
		res = p.Compose()
		if !res.Consumers.On || !slices.Equal(res.Consumers.Created, []string{"EVENTS.b_mod-c"}) {
			t.Fatalf("once handed away: %+v", res.Consumers)
		}
		var made map[string]any
		for _, c := range b.consumers["EVENTS"] {
			if c["name"] == "b_mod-c" {
				made = c
			}
		}
		if made == nil || made["max_deliver"] != 5 || !slices.Contains(made["filters"].([]string), "mesh.mod.mod-y.event.done") {
			t.Errorf("b_mod-c was made as %v, not as the controller makes it", made)
		}
		res = p.Compose()
		if len(res.Consumers.Created) != 0 || len(res.Consumers.Missing) != 0 || len(b.consumerCreates) != 1 {
			t.Errorf("a consumer the bus holds was asked again: %+v, %v", res.Consumers, b.consumerCreates)
		}
		// A held consumer that differs is never changed by a pass: it is raised as a condition naming it, and brought to
		// the composed configuration only by hand (grants_consumer_match), never while the controller holds the lease.
		var said []asks.Condition
		p.Say = func(c asks.Condition) error { said = append(said, c); return nil }
		made["max_deliver"] = 9
		res = p.Compose()
		if len(res.Consumers.Differ) != 1 || !strings.Contains(res.Consumers.Differ[0], "EVENTS.b_mod-c: max deliver 9") ||
			len(said) != 1 || said[0].Key != grants.ConsumerDiffersCondition || said[0].State != asks.StateRaised ||
			!strings.Contains(said[0].Explanation, "EVENTS.b_mod-c") {
			t.Fatalf("a differing consumer: %+v, said %+v", res.Consumers, said)
		}
		b.put(grants.ReadLease, grants.LeaseKey, map[string]any{"instance": "novox/2/2026-10-27", "epoch": 58})
		if _, err := p.MatchConsumer("EVENTS", "b_mod-c"); err == nil || !strings.Contains(err.Error(), "controller holds the lease") {
			t.Errorf("matched by hand under the controller's lease: %v", err)
		}
		b.put(grants.ReadLease, grants.LeaseKey, map[string]any{"handed-to": "the operator's hand-over"})
		if _, err := p.MatchConsumer("EVENTS", "b_nothing"); err == nil {
			t.Error("a consumer the records do not compose was asked to match")
		}
		if _, err := p.MatchConsumer("EVENTS", "b_mod-c"); err != nil {
			t.Fatal(err)
		}
		res = p.Compose()
		if !slices.Contains(b.consumerCreates, "match EVENTS.b_mod-c") || made["max_deliver"] != 5 || len(res.Consumers.Matched) != 1 {
			t.Errorf("the ask to match: %+v, %v", res.Consumers, b.consumerCreates)
		}
		res = p.Compose()
		if len(res.Consumers.Differ) != 0 || said[len(said)-1].State != asks.StateCleared {
			t.Errorf("once matched: %+v, said %+v", res.Consumers, said)
		}
	})
}

type fakeAsker struct {
	asks    []asks.Ask
	wheres  map[string]*asks.Warrant // the router's warrants, by ask
	fail    bool
	cancels []string
	// takeErr makes Take fail as the asker does when the part's own record cannot be reached: no handling, an error.
	takeErr error
}

func (f *fakeAsker) Cancel(id string) error { f.cancels = append(f.cancels, id); return nil }

// fakeObjects is the part's object bucket of sealed lists.
type fakeObjects struct{ objects map[string][]byte }

func (o *fakeObjects) PutObject(name string, data []byte) error {
	if o.objects == nil {
		o.objects = map[string][]byte{}
	}
	o.objects[name] = data
	return nil
}

func (o *fakeObjects) DeleteObject(name string) error { delete(o.objects, name); return nil }

func (f *fakeAsker) Ask(a asks.Ask) error {
	if f.fail {
		return errors.New("the bus refused the publish")
	}
	f.asks = append(f.asks, a)
	return nil
}

func (f *fakeAsker) Where(id string) (string, *asks.Warrant, error) { return "open", f.wheres[id], nil }

// Take hands the warrant to act as the SDK's asker does for one that chose, and records any other.
func (f *fakeAsker) Take(w asks.Warrant, act func(asks.Option, asks.Warrant) error) (asker.Handled, error) {
	if f.takeErr != nil {
		return "", f.takeErr
	}
	if w.Outcome != asks.OutcomeChosen {
		return asker.Recorded, nil
	}
	return asker.Acted, act(asks.Option{ID: w.Option}, w)
}

func nonNil(s []string) []string {
	if s == nil {
		return []string{}
	}
	return s
}

// fakeWatcher refuses a state's first watches as told, and hands changes to the watches it opened.
// refusingStreams is the bus with nats_streams refused: what the bus holds cannot be read.
type refusingStreams struct{ *fakeBus }

func (r refusingStreams) Call(key string, body any) (json.RawMessage, error) {
	if key == grants.CallStreams {
		return nil, errors.New("refused")
	}
	return r.fakeBus.Call(key, body)
}

type fakeWatcher struct {
	mu      sync.Mutex
	refuse  map[string]int
	changes map[string]func(string, []byte)
	opened  chan string
}

func (w *fakeWatcher) Watch(state string, changed func(string, []byte), _ func(error)) error {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.refuse[state] > 0 {
		w.refuse[state]--
		return errors.New("Permissions Violation for Publish to $JS.API.STREAM.INFO.KV_" + state)
	}
	if w.changes == nil {
		w.changes = map[string]func(string, []byte){}
	}
	w.changes[state] = changed
	w.opened <- state
	return nil
}

func (w *fakeWatcher) change(state, key string) {
	w.mu.Lock()
	h := w.changes[state]
	w.mu.Unlock()
	h(key, []byte(`{}`))
}

func waitOpened(t *testing.T, w *fakeWatcher, state string) {
	t.Helper()
	deadline := time.After(10 * time.Second)
	for {
		select {
		case s := <-w.opened:
			if s == state {
				return
			}
		case <-deadline:
			t.Fatalf("%s was never watched", state)
		}
	}
}

func waitFor(t *testing.T, ok func() bool) {
	t.Helper()
	for end := time.Now().Add(10 * time.Second); time.Now().Before(end); time.Sleep(10 * time.Millisecond) {
		if ok() {
			return
		}
	}
	t.Fatal("never came")
}