S6: the bus keeper treats a none-yet catalog half as not yet viewed

PlanCatalog plans nothing, deletes no plans key and orphans no entry while the
catalog half lists no module before any was seen; the first revision with
entries plans as before.

Builds: design 47 G A-367 (G-22-lead-answers-2.md), W22/Q4 of start-waits.md

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

modules/mesh-build-go/buildstep/doc.go

@@ -0,0 +1,3 @@
+// Package buildstep is kept empty as a bridge: the running pre-G indexer publishes mesh-catalog's packages only while
+// every package directory it published before is in the tree. It goes once G's indexer runs.
+package buildstep

modules/nats/internal/keeper/keeper.go

@@ -456,7 +456,8 @@ func (k *Keeper) statusWritten(s Status, err error) {
 // watched branch's newest revision is applied (Heard), a module of the new form that sends gets its sent store, a drift
 // between branches is said once, and a module in no watched branch's newest revision has its plans key deleted, its
 // entries then orphans. Before every watched branch has its first view it plans nothing, and says what it waits for in
-// its status; the first plan checks what is held.
+// its status, and an answer listing no module before one has listed any is the same (none-yet); the first plan checks what
+// is held.
 func (k *Keeper) PlanCatalog() error {
 	at := k.now()
 	view, err := k.Catalog()
@@ -466,6 +467,15 @@ func (k *Keeper) PlanCatalog() error {
 	}
 	k.mu.Lock()
 	first := !k.viewed
+	// A catalog half with no module in it before any has been seen is a trunk with no revision yet (`none-yet`, design 47
+	// G A-367): not yet viewed, so nothing is planned, no plan deleted and no entry made an orphan for want of knowledge.
+	if first && len(view.Modules) == 0 {
+		k.mu.Unlock()
+		k.setStatus(func(s *Status) {
+			s.FirstView.Asked, s.FirstView.Error = at, "the catalog half lists no module yet (none-yet): nothing is planned or orphaned until a revision lists one"
+		})
+		return nil
+	}
 	k.viewed = true
 	k.mu.Unlock()
 	var revision uint64

modules/nats/internal/keeper/keeper_test.go

@@ -450,6 +450,9 @@ func TestTheKeeperMakesWhatAVerdictAsksForAndSaysIt(t *testing.T) {
 			if len(bus.created) != 0 {
 				t.Fatalf("created %v before the first view", bus.created)
 			}
+			k.Catalog = func() (CatalogView, error) {
+				return CatalogView{Modules: []CatalogModule{{Accepted: Accepted{Module: "m", Digest: "d1", Revision: 3, BusState: []catalogue.BusStateEntry{drafts}}}}}, nil
+			}
 			if err := k.PlanCatalog(); err != nil {
 				t.Fatal(err)
 			}
@@ -541,6 +544,37 @@ func TestTheKeeperMakesWhatAVerdictAsksForAndSaysIt(t *testing.T) {
 				t.Errorf("old sections %d: 8 MiB counted", k.Status().OldBytes)
 			}
 		}},
+		// A-367: a trunk with no revision yet (none-yet) is not yet viewed: nothing is planned, deleted or orphaned.
+		{"a none-yet catalog half plans nothing and orphans nothing until a module is listed", func(t *testing.T, k *Keeper, bus *fakeBus, out *said) {
+			k.Heard(Accepted{Module: "m", Revision: 9, BusState: []catalogue.BusStateEntry{drafts}})
+			k.Catalog = func() (CatalogView, error) {
+				return CatalogView{Modules: []CatalogModule{{Accepted: Accepted{Module: "m", Revision: 9, BusState: []catalogue.BusStateEntry{drafts}}}}}, nil
+			}
+			_ = k.PlanCatalog()
+			k.mu.Lock()
+			k.viewed = false
+			k.mu.Unlock()
+			k.Catalog = func() (CatalogView, error) { return CatalogView{}, nil }
+			if err := k.PlanCatalog(); err != nil {
+				t.Fatal(err)
+			}
+			if _, ok := k.planned("m"); !ok {
+				t.Error("m's plan is deleted by a none-yet view")
+			}
+			if a := k.Held()["m"]; a.Made["drafts"].Orphaned {
+				t.Errorf("held %+v: drafts orphaned by a none-yet view", a)
+			}
+			if k.Viewed() || !strings.Contains(k.Status().FirstView.Error, "none-yet") {
+				t.Errorf("viewed %v, status %+v: none-yet is not a first view and says so", k.Viewed(), k.Status().FirstView)
+			}
+			k.Catalog = func() (CatalogView, error) {
+				return CatalogView{Modules: []CatalogModule{{Accepted: Accepted{Module: "m", Revision: 10, BusState: []catalogue.BusStateEntry{drafts}}}}}, nil
+			}
+			_ = k.PlanCatalog()
+			if !k.Viewed() || k.Status().FirstView.Error != "" {
+				t.Error("the first revision with entries is viewed and plans as before")
+			}
+		}},
 		// §538: a module in no watched branch's newest revision has its plans key deleted, its entries then orphans.
 		{"a module no watched branch lists loses its plan, its entries orphans", func(t *testing.T, k *Keeper, bus *fakeBus, out *said) {
 			k.Catalog = func() (CatalogView, error) {
@@ -1240,9 +1274,11 @@ func TestTheKeeperMakesWhatAVerdictAsksForAndSaysIt(t *testing.T) {
 	} {
 		t.Run(row.name, func(t *testing.T) {
 			k, bus, _, out := newKeeper(CatalogView{})
-			if err := k.PlanCatalog(); err != nil {
-				t.Fatal(err)
-			}
+			// The rows start after the first view: an empty answer is none-yet (A-367), so the view is marked answered here.
+			k.mu.Lock()
+			k.viewed = true
+			k.mu.Unlock()
+			k.setStatus(func(s *Status) { s.FirstView.Asked, s.FirstView.Answered = k.now(), k.now() })
 			row.run(t, k, bus, out)
 		})
 	}