[Rest Api Compatibility] Allow copy_settings flag for resize operations (#75184)

previously removed in #38514, deprecated in 7.x and defaulted to true.
With rest api compatibility and when value is true it is ignored and warning is emitted
when value is false, an exception is thrown

relates #51816

Author: pgomulka

rest-api-spec/build.gradle

@@ -91,8 +91,6 @@ tasks.named("yamlRestCompatTest").configure {
     'indices.open/10_basic/?wait_for_active_shards=index-setting',
     // not fixing this in #70966
     'indices.put_template/11_basic_with_types/Put template with empty mappings',
-    'indices.shrink/30_copy_settings/Copy settings during shrink index',
-    'indices.split/30_copy_settings/Copy settings during split index',
     'mlt/20_docs/Basic mlt query with docs',
     'mlt/30_unlike/Basic mlt query with unlike',
     'search.aggregation/200_top_hits_metric/top_hits aggregation with sequence numbers',

server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestResizeHandler.java

@@ -12,6 +12,9 @@
 import org.elasticsearch.action.admin.indices.shrink.ResizeType;
 import org.elasticsearch.action.support.ActiveShardCount;
 import org.elasticsearch.client.node.NodeClient;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.core.Booleans;
+import org.elasticsearch.core.RestApiVersion;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.action.RestToXContentListener;
@@ -23,6 +26,7 @@
 import static org.elasticsearch.rest.RestRequest.Method.PUT;
 
 public abstract class RestResizeHandler extends BaseRestHandler {
+    private static final DeprecationLogger deprecationLogger =  DeprecationLogger.getLogger(RestResizeHandler.class);
 
     RestResizeHandler() {
     }
@@ -34,6 +38,15 @@ public abstract class RestResizeHandler extends BaseRestHandler {
 
     @Override
     public final RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
+        if (request.getRestApiVersion() == RestApiVersion.V_7 && request.hasParam("copy_settings")) {
+            deprecationLogger.compatibleApiWarning("copy_settings", "parameter [copy_settings] is deprecated and will be removed in 8.0.0");
+
+            final String rawCopySettings = request.param("copy_settings");
+            final boolean copySettings = Booleans.parseBoolean(rawCopySettings);
+            if (copySettings == false) {
+                throw new IllegalArgumentException("parameter [copy_settings] can not be explicitly set to [false]");
+            }
+        }
         final ResizeRequest resizeRequest = new ResizeRequest(request.param("target"), request.param("index"));
         resizeRequest.setResizeType(getResizeType());
         request.applyContentParser(resizeRequest::fromXContent);