fix: replica count for new deployment (argoproj#1449)

fix: replica count for new deployment (argoproj#1449)

Signed-off-by: hari rongali <[email protected]>

Author: harikrongali

utils/replicaset/canary.go

@@ -187,12 +187,11 @@ func CalculateReplicaCountsForCanary(rollout *v1alpha1.Rollout, newRS *appsv1.Re
 	}
 
 	scaleDownCount := replicasToScaleDown - minAvailableReplicaCount
-
 	if !isIncreasing {
 		// Skip scalingDown Stable replicaSet when Canary availability is not taken into calculation for scaleDown
 		newRSReplicaCount = calculateScaleDownReplicaCount(newRS, desiredNewRSReplicaCount, scaleDownCount, newRSReplicaCount)
 		newRSReplicaCount, stableRSReplicaCount = adjustReplicaWithinLimits(newRS, stableRS, newRSReplicaCount, stableRSReplicaCount, maxReplicaCountAllowed, minAvailableReplicaCount)
-	} else {
+	} else if scaleStableRS {
 		// Skip scalingDown canary replicaSet when StableSet availability is not taken into calculation for scaleDown
 		stableRSReplicaCount = calculateScaleDownReplicaCount(stableRS, desiredStableRSReplicaCount, scaleDownCount, stableRSReplicaCount)
 		stableRSReplicaCount, newRSReplicaCount = adjustReplicaWithinLimits(stableRS, newRS, stableRSReplicaCount, newRSReplicaCount, maxReplicaCountAllowed, minAvailableReplicaCount)

utils/replicaset/canary_test.go

@@ -602,6 +602,15 @@ func TestCalculateReplicaCountsForCanary(t *testing.T) {
 	}
 }
 
+func TestCalculateReplicaCountsForNewDeployment(t *testing.T) {
+	rollout := newRollout(10, 10, intstr.FromInt(0), intstr.FromInt(1), "canary", "stable", nil, nil)
+	stableRS := newRS("stable", 10, 0)
+	newRS := newRS("stable", 10, 0)
+	newRSReplicaCount, stableRSReplicaCount := CalculateReplicaCountsForCanary(rollout, newRS, stableRS, nil)
+	assert.Equal(t, int32(10), newRSReplicaCount)
+	assert.Equal(t, int32(0), stableRSReplicaCount)
+}
+
 func TestCalculateReplicaCountsForCanaryTrafficRouting(t *testing.T) {
 	rollout := newRollout(10, 10, intstr.FromInt(0), intstr.FromInt(1), "canary", "stable", nil, nil)
 	rollout.Spec.Strategy.Canary.TrafficRouting = &v1alpha1.RolloutTrafficRouting{}