The indexer follows its seat list through the wiring every part shares, seatlist.Part, not a copy of its own (milestone 47/G W4.10, W1.9)

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

Builds: design 47 G §204

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/seatlist.go

@@ -9,7 +9,6 @@ import (
 
 	"github.com/nats-io/nats.go/jetstream"
 
-	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/process"
 	"git.novox.be/novox/mesh-sdk/go/seatlist"
 	"git.novox.be/novox/mesh-sdk/go/views"
@@ -107,19 +106,15 @@ func (b *seatBus) said(c index.SeatDefinitionChanged) {
 	}
 }
 
-// followSeatList starts the indexer's reader of its own seat list and gives catalogue what it holds at every change, and wraps
-// say so that each move the indexer says is also heard by the reader. It returns the reader, whose status the indexer's health
-// can show.
-func followSeatList(bus *seatBus, say func(context.Context, index.SeatDefinitionChanged) error, logf func(string, ...any)) (*seatlist.Reader, func(context.Context, index.SeatDefinitionChanged) error) {
-	reader, err := seatlist.Start(seatlist.Config{Bus: bus, Bootstrap: seatlist.Bootstrapped(),
-		OnChange: func(seats []catalogue.Seat) { catalogue.UseSeats(seats) }})
-	if err != nil {
-		logf("the indexer cannot follow its seat list: %v", err)
-	}
-	if reader != nil {
-		catalogue.UseSeats(reader.Seats())
-	}
-	return reader, func(ctx context.Context, c index.SeatDefinitionChanged) error {
+// followSeatList starts the indexer's reader of its own seat list through the wiring every part shares (mesh-sdk
+// seatlist.Part, novox/hq ADR 0636 §7), which gives catalogue what it holds at every change, and wraps say so that each move
+// the indexer says is also heard by the reader. Its two tools are not served: the indexer's process serves no request
+// subject (ADR 0437 §4), and its list is its own state seat-definitions, which indexer_seat_definition and the seat's verb
+// seat-definitions read. It returns the part, whose status the indexer's health can show.
+func followSeatList(bus *seatBus, say func(context.Context, index.SeatDefinitionChanged) error, logf func(string, ...any)) (*seatlist.Part, func(context.Context, index.SeatDefinitionChanged) error) {
+	part := seatlist.NewPart(toolPrefix, nil)
+	part.Follow(bus, nil, logf)
+	return part, func(ctx context.Context, c index.SeatDefinitionChanged) error {
 		if err := say(ctx, c); err != nil {
 			return err
 		}
@@ -138,13 +133,11 @@ type bucket interface {
 // readWhenBound has the reader read the list again as each of the states it is answered from is bound. The reader starts before
 // they are, its first read finds them missing and leaves it unread, and the indexer's own events (said) are the only other thing
 // that reads it again: a trunk that moves no definition after a start would leave the list unread for good (ADR 0636 §1).
-func readWhenBound(reader *seatlist.Reader, states ...bucket) {
-	if reader == nil {
-		return
-	}
+func readWhenBound(part *seatlist.Part, states ...bucket) {
 	for _, state := range states {
-		state.Ready(func(jetstream.KeyValue) {
-			reader.ReloadIfUnread()
-		})
+		state.Ready(func(jetstream.KeyValue) { part.EventsLive() })
 	}
 }
+
+// toolPrefix is the prefix of the indexer's tools, its manifest's slug.
+const toolPrefix = "indexer"

modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/seatlist_test.go

@@ -44,13 +44,14 @@ func (b *awaitedFake) Ready(f func(jetstream.KeyValue)) { b.ready = append(b.rea
 func TestTheSeatListIsReadAgainWhenItsStatesAreBound(t *testing.T) {
 	src := &unboundSource{}
 	bus := &seatBus{defs: src, marks: src}
-	reader, _ := followSeatList(bus, nil, t.Logf)
+	part, _ := followSeatList(bus, nil, t.Logf)
+	reader := part.Reader()
 	<-reader.Ready()
 	if reader.Status().Heard {
 		t.Fatal("the list was read with its states missing")
 	}
 	b := &awaitedFake{}
-	readWhenBound(reader, b)
+	readWhenBound(part, b)
 	src.mu.Lock()
 	src.bound = true
 	src.mu.Unlock()