Forget a runtime's old instance once it answers under a new one, so a restart is not reported as a missed answer

node-tools/internal/console/runtimes.go

@@ -81,6 +81,17 @@ func (s *Surface) remember(x *index) {
 		heard[k] = true
 		s.runtimes[k] = seen
 	}
+	// A runtime restarted answers under a new instance id: the old one is gone, not silent, and saying
+	// it was missed would hide nothing but cry wolf after every restart.
+	now := map[string]bool{}
+	for k := range heard {
+		now[s.runtimes[k].Name+"@"+s.runtimes[k].Machine] = true
+	}
+	for k, r := range s.runtimes {
+		if !heard[k] && r.Machine != "" && now[r.Name+"@"+r.Machine] {
+			delete(s.runtimes, k)
+		}
+	}
 	silent := map[string]string{}
 	for _, u := range x.Discovery.Silent {
 		silent[runtimeKey(u.Name, u.ID)] = fmt.Sprintf("it answered PING; what it serves did not arrive within %s", announce.Patience)

node-tools/internal/console/runtimes_test.go

@@ -198,3 +198,22 @@ func TestARuntimeHeardBeforeAndNotNowIsNamed(t *testing.T) {
 		t.Errorf("%v", err)
 	}
 }
+
+// A runtime restarted answers under a new instance id; its old instance is gone, not unheard.
+func TestARestartedRuntimeIsNotNamedUnheard(t *testing.T) {
+	heard := func(id string) *index {
+		return &index{Modules: map[string]*moduleInfo{}, Recorded: map[string][]string{}, Discovery: announce.Discovery{At: time.Now().UTC(),
+			Heard: []announce.Heard{{Info: micro.Info{ServiceIdentity: micro.ServiceIdentity{Name: "node-tools", ID: id,
+				Metadata: map[string]string{"node": "laptop"}}}}}}}
+	}
+	s := &Surface{}
+	s.remember(heard("before-restart"))
+	after := heard("after-restart")
+	s.remember(after)
+	if len(after.Unheard) != 0 {
+		t.Errorf("a restarted runtime was named unheard: %+v", after.Unheard)
+	}
+	if len(s.runtimes) != 1 {
+		t.Errorf("the old instance is still kept: %d runtimes", len(s.runtimes))
+	}
+}