Carry a channel's capabilities on its claim and tell the router every kind, so an answer is judged by the controller's record and not the channel's word

internal/broker/membership.go

@@ -84,6 +84,8 @@ type Placements struct {
 	// Interchangeable is each module whose definition says its instances are the same anywhere,
 	// so the module's plain subject is issued to all of them in one queue.
 	Interchangeable map[string]bool
+	// Kinds is every kind held of a kinded bench, by whom and with what capabilities (ADR 0259 §5).
+	Kinds []KindHeld
 }
 
 // AnswersForTheModule says whether an instance of a module on one machine is issued the module's
@@ -115,8 +117,18 @@ func MembershipFor(node string, d Declared, where Placements) Membership {
 		}
 	}
 	m.State = stateIssuedFor(d, node)
-	if t := SeatTrafficOf(d.Module, d.Holds, d.Uses, d.Watches); len(t.Publish)+len(t.Subscribe)+
+	t := SeatTrafficOf(d.Module, d.Holds, d.Uses, d.Watches)
-		len(t.Answers)+len(t.Workers)+len(t.Records) > 0 {
+	for _, s := range append(append([]Seat{}, d.Uses...), d.Watches...) {
+		if !s.Kinded {
+			continue
+		}
+		for _, k := range where.Kinds {
+			if k.Seat == s.Name && !kindListed(t.Kinds, k) {
+				t.Kinds = append(t.Kinds, k)
+			}
+		}
+	}
+	if len(t.Publish)+len(t.Subscribe)+len(t.Answers)+len(t.Workers)+len(t.Records)+len(t.Kinds) > 0 {
 		m.SeatTraffic = &t
 	}
 	if len(d.Invokes) > 0 {
@@ -155,5 +167,34 @@ func PlacementsOf(r Records, interchangeable map[string]bool) Placements {
 	for _, nodes := range p.Nodes {
 		sort.Strings(nodes)
 	}
+	for node, declared := range r.Assigned {
+		for _, d := range declared {
+			for _, s := range d.Holds {
+				if s.Kinded && s.Kind != "" {
+					p.Kinds = append(p.Kinds, KindHeld{Seat: s.Name, Kind: s.Kind, Module: d.Module, Node: node,
+						Capabilities: s.Capabilities})
+				}
+			}
+		}
+	}
+	sort.Slice(p.Kinds, func(i, j int) bool {
+		a, b := p.Kinds[i], p.Kinds[j]
+		if a.Seat != b.Seat {
+			return a.Seat < b.Seat
+		}
+		if a.Kind != b.Kind {
+			return a.Kind < b.Kind
+		}
+		return a.Node < b.Node
+	})
 	return p
 }
+
+func kindListed(list []KindHeld, k KindHeld) bool {
+	for _, x := range list {
+		if x.Seat == k.Seat && x.Kind == k.Kind && x.Module == k.Module && x.Node == k.Node {
+			return true
+		}
+	}
+	return false
+}

internal/broker/nats.go

@@ -75,6 +75,8 @@ type Seat struct {
 	Proofs []string
 	// Records are the holder's buckets, by their full name, each user reads under its own name.
 	Records []string
+	// Capabilities are what this principal's claim of a kinded bench promises (ADR 0234 §2).
+	Capabilities []string
 }
 
 // A Principal is one user of the bus. Its permissions are derived from what it declares and

internal/broker/seattraffic.go

@@ -47,6 +47,19 @@ type SeatTraffic struct {
 	Workers []Worker `json:"workers,omitempty"`
 	// Records is the direct-get subjects of the records it reads under its own name.
 	Records []string `json:"records,omitempty"`
+	// Kinds are the holders of every kinded bench it uses or watches, with what each promises: the one
+	// account of which channel is which, and what it can carry, that the router judges an answer by. The
+	// controller's, from the claims, never a channel's word (novox/hq ADR 0259 §5).
+	Kinds []KindHeld `json:"kinds,omitempty"`
+}
+
+// KindHeld is one kind of a kinded bench and who holds it.
+type KindHeld struct {
+	Seat         string   `json:"seat"`
+	Kind         string   `json:"kind"`
+	Module       string   `json:"module"`
+	Node         string   `json:"node"`
+	Capabilities []string `json:"capabilities,omitempty"`
 }
 
 // KindedBenches are the seats that may be kinded (ADR 0234 §2): making another is a decision, recorded.

internal/broker/seattraffic_test.go

@@ -238,3 +238,35 @@ func TestASeatWithoutTheNewRulesIsComposedAsBefore(t *testing.T) {
 		t.Error("an old seat's holder lost its accept")
 	}
 }
+
+// The router learns which channel is which, and what each promises, from the controller's membership:
+// the claims, never a channel's word (ADR 0259 §5).
+func TestTheRoutersMembershipNamesEveryKindAndItsCapabilities(t *testing.T) {
+	tg := channelSeat("telegram")
+	tg.Capabilities = []string{"choice", "verified-sender"}
+	desk := channelSeat("desktop")
+	desk.Capabilities = []string{"choice"}
+	router := Declared{Module: "messenger", Holds: []Seat{operatorChannel()}, Uses: []Seat{channelSeat("")}}
+	records := Records{Nodes: []string{"anchor", "laptop"}, Assigned: map[string][]Declared{
+		"anchor": {router, {Module: "telegram", Holds: []Seat{tg}}},
+		"laptop": {{Module: "desk-channel", Holds: []Seat{desk}}},
+	}}
+	where := PlacementsOf(records, nil)
+	m := MembershipFor("anchor", router, where)
+	if m.SeatTraffic == nil || len(m.SeatTraffic.Kinds) != 2 {
+		t.Fatalf("the router is not told the kinds: %+v", m.SeatTraffic)
+	}
+	byKind := map[string]KindHeld{}
+	for _, k := range m.SeatTraffic.Kinds {
+		byKind[k.Kind] = k
+	}
+	if k := byKind["telegram"]; k.Module != "telegram" || k.Node != "anchor" || !namesVerb(k.Capabilities, "verified-sender") {
+		t.Errorf("telegram is %+v", k)
+	}
+	if k := byKind["desktop"]; k.Module != "desk-channel" || namesVerb(k.Capabilities, "verified-sender") {
+		t.Errorf("the desk is %+v", k)
+	}
+	if other := MembershipFor("anchor", Declared{Module: "mesh-delivery", Uses: []Seat{operatorChannel()}}, where); other.SeatTraffic != nil && len(other.SeatTraffic.Kinds) > 0 {
+		t.Error("an asker is told the channels")
+	}
+}

internal/catalogue/kinded_test.go

@@ -93,3 +93,24 @@ func TestEachKindIsItsOwnHolderWhenResolved(t *testing.T) {
 		t.Fatal("one kind held on two machines was not refused")
 	}
 }
+
+// A channel's capabilities come from the fixed vocabulary, and only a kinded claim carries any.
+func TestCapabilitiesAreTheVocabularysAndOnlyOnAKindedClaim(t *testing.T) {
+	good := aChannel("telegram", "telegram")
+	good.Claims[0].Capabilities = []string{"deliver", "choice", "verified-sender", "max-length:4096"}
+	if got := problemsFor(t, Shelf{"messenger": router(), "telegram": good}); got != "" {
+		t.Fatalf("the vocabulary was refused: %s", got)
+	}
+	bad := aChannel("telegram", "telegram")
+	bad.Claims[0].Capabilities = []string{"trusted", "max-length:lots"}
+	got := problemsFor(t, Shelf{"messenger": router(), "telegram": bad})
+	for _, w := range []string{`"trusted"`, `"max-length:lots"`} {
+		if !strings.Contains(got, w+", which channel-capabilities/1 does not have") {
+			t.Errorf("%s was not refused: %s", w, got)
+		}
+	}
+	odd := Manifest{Module: "odd", Claims: []Claim{{Name: "operator-channel", Scope: ScopeMesh, Capabilities: []string{"deliver"}}}}
+	if got := problemsFor(t, Shelf{"messenger": router(), "odd": odd}); !strings.Contains(got, "only a kinded bench's claim carries them") {
+		t.Errorf("capabilities on a seat that is not kinded stood: %s", got)
+	}
+}

internal/catalogue/manifest.go

@@ -67,6 +67,10 @@ type Claim struct {
 	// Kind is the kind this module holds a kinded bench as (novox/hq ADR 0234 §2, ADR 0259): `telegram`,
 	// `desktop`. Refused on any other seat, and a second claim of one kind is refused.
 	Kind string `json:"kind,omitempty"`
+	// Capabilities are what a channel of this kind promises, from the fixed vocabulary
+	// channel-capabilities/1 (novox/hq ADR 0234 §2): the router judges an answer by these, read from the
+	// controller's record of this claim and never from the channel.
+	Capabilities []string `json:"capabilities,omitempty"`
 }
 
 // ServesFor is what this claim offers a seat's protocol: the verbs it names, else the module's

internal/catalogue/seats_declared.go

@@ -2,6 +2,7 @@ package catalogue
 
 import (
 	"fmt"
+	"regexp"
 	"sort"
 	"strings"
 )
@@ -331,9 +332,43 @@ func CatalogueProblems(shelf Shelf) []string {
 	return problems
 }
 
+// ChannelCapabilities is the fixed vocabulary `channel-capabilities/1` (novox/hq ADR 0234 §2): a word
+// outside it is refused. `max-length:<N>` takes a number.
+var ChannelCapabilities = map[string]bool{
+	"deliver": true, "reaches-away": true, "loud": true, "silent": true, "edit": true,
+	"reaches-when-mesh-down": true, "private": true,
+	"choice": true, "reply": true, "threads": true, "operator-first": true,
+	"verified-sender": true, "exact-render": true, "code-factor": true, "key-factor": true,
+}
+
+var maxLength = regexp.MustCompile(`^max-length:[1-9][0-9]{0,6}$`)
+
+// capabilityProblems are the words of a claim outside the vocabulary, and capabilities on a claim of a
+// seat that is not kinded.
+func capabilityProblems(module string, c Claim, kinded bool) []string {
+	if len(c.Capabilities) == 0 {
+		return nil
+	}
+	if !kinded {
+		return []string{fmt.Sprintf("%s claims %s with capabilities, and only a kinded bench's claim carries them",
+			module, c.Name)}
+	}
+	var problems []string
+	for _, w := range c.Capabilities {
+		if !ChannelCapabilities[w] && !maxLength.MatchString(w) {
+			problems = append(problems, fmt.Sprintf(
+				"%s claims %s with the capability %q, which channel-capabilities/1 does not have", module, c.Name, w))
+		}
+	}
+	return problems
+}
+
 // kindProblems is a claim judged against a declared seat's kind: a kinded bench takes one claim per kind,
 // a usable name; any other seat takes none.
 func kindProblems(module string, c Claim, s SeatDeclaration, taken map[string]string) []string {
+	if problems := capabilityProblems(module, c, s.Kinded); len(problems) > 0 {
+		return problems
+	}
 	switch {
 	case !s.Kinded && c.Kind != "":
 		return []string{fmt.Sprintf("%s claims %s of kind %q, and only a kinded bench takes a kind",

internal/inventory/busrecords.go

@@ -183,6 +183,7 @@ func declaredFor(m catalogue.Manifest, seats map[string]catalogue.SeatDeclaratio
 		if s, hasAProtocol := seats[c.Name]; hasAProtocol {
 			held := asSeat(s, declarers[s.Name])
 			held.Kind = c.Kind
+			held.Capabilities = c.Capabilities
 			d.Holds = append(d.Holds, held)
 		}
 	}