Fix pkg/inventory/deployment.go:ForDeployments(): don't modify the de…

…ployment.spec.selector immutable field on update (#2380)

Signed-off-by: Serge Catudal <serge.catudal@gmail.com>

pkg/inventory/deployment.go

@@ -37,6 +37,11 @@ func ForDeployments(existing []appsv1.Deployment, desired []appsv1.Deployment) D
 			// we can't blindly DeepCopyInto, so, we select what we bring from the new to the old object
 			tp.Spec = v.Spec
 			tp.Spec = inject.PropagateOAuthCookieSecret(t.Spec, v.Spec)
+
+			// Deployment.Spec.Selector is an immutable field: we can't update
+			// this field with a new value, we MUST keep the original field value
+			tp.Spec.Selector = t.Spec.Selector
+
 			tp.ObjectMeta.OwnerReferences = v.ObjectMeta.OwnerReferences
 
 			for k, v := range v.ObjectMeta.Annotations {

pkg/inventory/deployment_test.go

@@ -140,3 +140,43 @@ func TestDeploymentSetReplicasWhenDesiredIsNotNil(t *testing.T) {
 	assert.Len(t, inv.Update, 1)
 	assert.Equal(t, desiredReplicas, *inv.Update[0].Spec.Replicas)
 }
+
+func TestDeploymentKeepSelectorOnUpdate(t *testing.T) {
+	desired := []appsv1.Deployment{{
+		Spec: appsv1.DeploymentSpec{
+			Selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{"foo": "bar"},
+			},
+		},
+	}}
+
+	desiredSelector := &metav1.LabelSelector{
+		MatchLabels: map[string]string{"keep": "me"},
+	}
+	existing := []appsv1.Deployment{{
+		Spec: appsv1.DeploymentSpec{
+			Selector: desiredSelector,
+		},
+	}}
+
+	inv := ForDeployments(existing, desired)
+	assert.Len(t, inv.Update, 1)
+	assert.Equal(t, desiredSelector, inv.Update[0].Spec.Selector)
+}
+
+func TestDeploymentSetSelectorOnCreate(t *testing.T) {
+	desiredSelector := &metav1.LabelSelector{
+		MatchLabels: map[string]string{"foo": "bar"},
+	}
+	desired := []appsv1.Deployment{{
+		Spec: appsv1.DeploymentSpec{
+			Selector: desiredSelector,
+		},
+	}}
+
+	existing := make([]appsv1.Deployment, 0)
+
+	inv := ForDeployments(existing, desired)
+	assert.Len(t, inv.Create, 1)
+	assert.Equal(t, desiredSelector, inv.Create[0].Spec.Selector)
+}