fix: abort scaledown stable RS for canary with traffic routing (argoproj#1331)

Signed-off-by: Hui Kang <[email protected]>

Author: huikang

test/e2e/istio_test.go

@@ -197,3 +197,30 @@ func (s *IstioSuite) TestIstioSubsetSplitSingleRoute() {
 		}).
 		ExpectRevisionPodCount("1", 1) // don't scale down old replicaset since it will be within scaleDownDelay
 }
+
+func (s *IstioSuite) TestIstioAbortUpdate() {
+	s.Given().
+		RolloutObjects("@istio/istio-host-split.yaml").
+		When().
+		ApplyManifests().
+		WaitForRolloutStatus("Healthy").
+		Then().
+		When().
+		AbortRollout().
+		WaitForRolloutStatus("Degraded").
+		Then().
+		ExpectRevisionPodCount("1", 1).
+		When().
+		UpdateSpec().
+		WaitForRolloutStatus("Paused").
+		Then().
+		When().
+		PromoteRollout().
+		WaitForRolloutStatus("Healthy").
+		Then().
+		When().
+		AbortRollout().
+		WaitForRolloutStatus("Degraded").
+		Then().
+		ExpectRevisionPodCount("2", 1)
+}

utils/replicaset/canary.go

@@ -293,7 +293,7 @@ func GetCurrentCanaryStep(rollout *v1alpha1.Rollout) (*v1alpha1.CanaryStep, *int
 
 // GetCanaryReplicasOrWeight either returns a static set of replicas or a weight percentage
 func GetCanaryReplicasOrWeight(rollout *v1alpha1.Rollout) (*int32, int32) {
-	if rollout.Status.PromoteFull {
+	if rollout.Status.PromoteFull || rollout.Status.CurrentPodHash == rollout.Status.StableRS {
 		return nil, 100
 	}
 	if scs := UseSetCanaryScale(rollout); scs != nil {