Restart an ask's bound at each run's start, also on the same node, so a step redelivered after its build module was replaced is not cut by the killed run's time (issue 1887, review: issue 734 path; ADR 0525 §6)

go/delivery/buildrun/asks.go

@@ -75,7 +75,7 @@ func (k Asker) Wait(ctx context.Context, a delivery.StepAsk) (delivery.Step, err
 			timer.Stop()
 		}
 	}()
-	running := ""
+	running, since := "", time.Time{}
 	for {
 		select {
 		case <-ctx.Done():
@@ -89,11 +89,12 @@ func (k Asker) Wait(ctx context.Context, a delivery.StepAsk) (delivery.Step, err
 			if step.State != delivery.StepRunning {
 				return step, nil
 			}
-			if k.Bound <= 0 || step.Node == running {
+			if k.Bound <= 0 || (step.Node == running && step.Started.Equal(since)) {
 				continue
 			}
-			// A node took the ask (or another took it after the first stopped): its step is bounded from its start.
-			running = step.Node
+			// A node took the ask, or took it again after its run stopped (another node, or the same node's build module
+			// replaced mid-run: a new start): its step is bounded from its own start.
+			running, since = step.Node, step.Started
 			left := k.Bound
 			if !step.Started.IsZero() {
 				left = time.Until(step.Started.Add(k.Bound))

go/delivery/buildrun/asks_test.go

@@ -49,3 +49,23 @@ func TestAnAskerPutsOnceAndReadsTheStep(t *testing.T) {
 		t.Fatal("a wait put an ask")
 	}
 }
+
+// Review (issue 734 path): an ask taken again by the same node (its build module replaced mid-run) is bounded from the
+// new run's start, so its pass is answered after the first run's bound would have ended the wait.
+func TestARedeliveryToTheSameNodeRestartsTheBound(t *testing.T) {
+	f := &FakeAsks{}
+	k := Asker{Publisher: f, Waiter: f, Bound: 60 * time.Millisecond}
+	const id = "mvl0frv18d1962"
+	first := time.Now()
+	f.Write(delivery.Step{ID: id, Node: "ace", State: delivery.StepRunning, Started: first})
+	go func() {
+		time.Sleep(40 * time.Millisecond)
+		f.Write(delivery.Step{ID: id, Node: "ace", State: delivery.StepRunning, Started: time.Now()})
+		time.Sleep(50 * time.Millisecond) // past the first run's bound, inside the second's
+		f.Write(delivery.Step{ID: id, Node: "ace", State: delivery.StepPassed, Started: time.Now()})
+	}()
+	step, err := k.Wait(context.Background(), goAsk(id))
+	if err != nil || step.State != delivery.StepPassed {
+		t.Fatalf("step %+v, %v, want the redelivered run's pass", step, err)
+	}
+}