Let a bundle pull one message from its listed worker and settle it, so a build module takes an ask only when it has a free slot, in its workers' order (issue 1887 A11, ADR 0525 §4)

node-tools/internal/launch/launch.go

@@ -288,7 +288,7 @@ func Start(module, entry string, env []string, mesh Bus, logf func(string, ...an
 							subscriber = c
 							mu.Unlock()
 							err = mesh.Subscribe(deliver)
-						case "mesh/seat.publish", "mesh/seat.prove", "mesh/seat.record", "mesh/seat.kinds":
+						case "mesh/seat.publish", "mesh/seat.prove", "mesh/seat.record", "mesh/seat.kinds", "mesh/seat.pull", "mesh/seat.settle":
 							var answered json.RawMessage
 							if answered, err = mesh.Seat(strings.TrimPrefix(m.Method, "mesh/seat."), m.Params, nil); err == nil {
 								result = answered

node-tools/internal/launch/seat_test.go

@@ -69,3 +69,45 @@ func TestABundleTakesASeatsWorkThroughItsOwnChannel(t *testing.T) {
 		t.Fatalf("the work was not handed to the bundle: %s %v", got, err)
 	}
 }
+
+// A bundle that pulls one ask from its worker when it is listed.
+const pullingBundle = `#!/bin/sh
+while IFS= read -r line; do
+  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
+  case "$line" in
+    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
+    *'"method":"tools/list"'*)
+      printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
+      printf '{"jsonrpc":"2.0","id":"p1","method":"mesh/seat.pull","params":{"worker":"SEAT_NODE_BUILD_GO_DELIVERY_worker","wait_ms":0}}\n' ;;
+  esac
+done
+`
+
+// 1887/A11: a bundle's pull reaches the runtime's bus from its own channel, as its other seat traffic does.
+func TestABundlePullsASeatsWorkThroughItsOwnChannel(t *testing.T) {
+	entry := filepath.Join(t.TempDir(), "bundle")
+	if err := os.WriteFile(entry, []byte(pullingBundle), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	b := &seating{}
+	l, err := Start("mesh-build-go", entry, os.Environ(), b, t.Logf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(l.Stop)
+	for i := 0; ; i++ {
+		b.mu.Lock()
+		verb, params := b.verb, b.params
+		b.mu.Unlock()
+		if verb == "pull" {
+			if params != `{"worker":"SEAT_NODE_BUILD_GO_DELIVERY_worker","wait_ms":0}` {
+				t.Fatalf("pulled with %s", params)
+			}
+			return
+		}
+		if i > 100 {
+			t.Fatal("the bundle's pull never reached the runtime")
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
+}