SMCP v2.3 adds an unexpected validation message, which does not occur when I apply the same resources using upstream Istio 1.14.3.

Similar upstream issue: https://github.com/istio/istio/issues/36160.

Steps to reproduce:

Deploy control plane:

oc apply -f - <<EOF apiVersion: maistra.io/v2
kind: ServiceMeshControlPlane
metadata:
  name: basic
  namespace: istio-system
spec:
  version: v2.3
  addons:
    kiali:
      enabled: false
    grafana:
      enabled: false
    prometheus:
      enabled: false
  general:
    validationMessages: true
  tracing:
    type: None
—
apiVersion: maistra.io/v1
kind: ServiceMeshMemberRoll
metadata:
  name: default
  namespace: istio-system
spec:
  members:
  - default
EOF

Deploy bookinfo app:

oc apply -n default -f https://raw.githubusercontent.com/maistra/istio/maistra-2.3/samples/bookinfo/platform/kube/bookinfo.yaml

Apply valid gateway and virtual service:

oc apply -n default -f https://raw.githubusercontent.com/maistra/istio/maistra-2.3/samples/bookinfo/networking/bookinfo-gateway.yaml

Get the created gateway:

oc get gateways bookinfo-gateway -n default -o yaml

The output should contain:

status:
  conditions:
  - lastProbeTime: "2022-10-17T12:01:58.045105172Z"
    lastTransitionTime: "2022-10-17T12:01:58.045106141Z"
    message: 32/32 proxies up to date.
    status: "True"
    type: Reconciled
  observedGeneration: "1"
  validationMessages:
  - documentationUrl: https://istio.io/v1.14/docs/reference/config/analysis/ist0101/
    level: ERROR
    type:
      code: IST0101

For more details analyze resources with istioctl:

curl https://raw.githubusercontent.com/maistra/istio/maistra-2.3/samples/bookinfo/networking/bookinfo-gateway.yaml | istioctl analyze -n default

You should get:

Error [IST0101] (Gateway default/bookinfo-gateway) Referenced selector not found: "istio=ingressgateway"

This error does not occur when using upstream Istio 1.14.3.