[SPARK-59540] Warn about deprecated Helm enable keys via NOTES.txt

.github/workflows/build_and_test.yml

@@ -350,3 +350,16 @@ jobs:
             | grep -q 'spark.kubernetes.operator.dynamicConfig.enabled=true'; then
             echo "dynamicConfig enabled with enable=false"; exit 1
           fi
+      - name: Validate the deprecated helm key warning
+        run: |
+          # `helm template` skips NOTES.txt, so the warning is only observable through an
+          # install. `--dry-run=client` renders it without reaching a cluster.
+          notes=$(helm install spark build-tools/helm/spark-kubernetes-operator --dry-run=client \
+            --set operatorDeployment.networkPolicy.enable=true \
+            --set operatorConfiguration.dynamicConfig.enable=true)
+          echo "$notes" | grep -q 'operatorDeployment.networkPolicy.enable is deprecated'
+          echo "$notes" | grep -q 'operatorConfiguration.dynamicConfig.enable is deprecated'
+          notes=$(helm install spark build-tools/helm/spark-kubernetes-operator --dry-run=client)
+          if echo "$notes" | grep -q 'is deprecated'; then
+            echo "Deprecation warning printed without a legacy key"; exit 1
+          fi

build-tools/helm/spark-kubernetes-operator/templates/NOTES.txt

@@ -0,0 +1,31 @@
+{{- /*
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements.  See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/ -}}
+Apache Spark Kubernetes Operator {{ .Chart.AppVersion }} is installed.
+{{- if hasKey (.Values.operatorDeployment.networkPolicy | default dict) "enable" }}
+
+WARNING: operatorDeployment.networkPolicy.enable is deprecated, use
+         operatorDeployment.networkPolicy.enabled instead. The legacy key is still honored:
+         the NetworkPolicy is created when either key is true. It will be removed in chart
+         2.0.0, see SPARK-59533.
+{{- end }}
+{{- if hasKey (.Values.operatorConfiguration.dynamicConfig | default dict) "enable" }}
+
+WARNING: operatorConfiguration.dynamicConfig.enable is deprecated, use
+         operatorConfiguration.dynamicConfig.enabled instead. The legacy key is still
+         honored: hot properties loading is enabled when either key is true. It will be
+         removed in chart 2.0.0, see SPARK-59533.
+{{- end }}