Bind a stream consumer again when the bus ends its loop, so a module is not left deaf when the controller deletes and makes again a consumer it cannot narrow (hq issue 725)

node-tools/internal/bus/streams_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -196,3 +197,84 @@ func TestAConsumerNamedBeforeItExistsIsBoundOnceItDoes(t *testing.T) {
 		return nil
 	})
 }
+
+// novox/hq ADR 0363 §6 (issue 725): a consumer the controller deletes and makes again under the same name, its
+// membership unchanged, is bound again, and what is published after is heard — the module does not go deaf.
+func TestAConsumerDeletedAndMadeAgainIsHeardAgain(t *testing.T) {
+	restore := bus.RebindEvery
+	bus.RebindEvery = 200 * time.Millisecond
+	t.Cleanup(func() { bus.RebindEvery = restore })
+	reader := mt.MembershipOf("reader", "anchor", false, nil)
+	reader.Hears = []bus.HeardIssued{{Stream: "MAIL", Consumer: "anchor_reader"}}
+	mesh, conn := streamMesh(t, reader)
+	mesh.Consumer(t, "anchor", "reader", []string{"mesh.mod.alpha.event.>"}, 5*time.Second)
+	mesh.ConsumerOn(t, "MAIL", "anchor", "reader", []string{"mesh.stream.mail.event.>"}, 5*time.Second)
+	logs := &syncLogs{}
+	conn.Logf = logs.Logf
+
+	var mu sync.Mutex
+	heard := 0
+	stop, err := conn.ConsumeAs("reader", func(env bus.Envelope) error {
+		if env.Key == "mail.mail.home.message.added" {
+			mu.Lock()
+			heard++
+			mu.Unlock()
+		}
+		return nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(stop)
+	count := func() int {
+		mu.Lock()
+		defer mu.Unlock()
+		return heard
+	}
+	mesh.Emit(t, "mesh.stream.mail.event.mail.home.message.added", map[string]any{"n": 1})
+	mt.Until(t, func() error {
+		if count() != 1 {
+			return errors.New("the first event on MAIL was not heard")
+		}
+		return nil
+	})
+
+	mesh.RemoveConsumer(t, "MAIL", "anchor", "reader")
+	mt.Until(t, func() error {
+		if !logs.Has("stopped hearing MAIL") {
+			return errors.New("the end of the loop was not said")
+		}
+		return nil
+	})
+	mesh.ConsumerOn(t, "MAIL", "anchor", "reader", []string{"mesh.stream.mail.event.>"}, 5*time.Second)
+	mesh.Emit(t, "mesh.stream.mail.event.mail.home.message.added", map[string]any{"n": 2})
+	mt.Until(t, func() error {
+		if count() != 2 {
+			return fmt.Errorf("heard %d events on MAIL after its consumer was made again, want 2", count())
+		}
+		return nil
+	})
+}
+
+// syncLogs keeps what the runtime says, from any goroutine.
+type syncLogs struct {
+	mu    sync.Mutex
+	lines []string
+}
+
+func (l *syncLogs) Logf(format string, args ...any) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.lines = append(l.lines, fmt.Sprintf(format, args...))
+}
+
+func (l *syncLogs) Has(fragment string) bool {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	for _, line := range l.lines {
+		if strings.Contains(line, fragment) {
+			return true
+		}
+	}
+	return false
+}