deserializing unknown key error response (#1041) (#1042)

Co-authored-by: Laura Trotta <[email protected]>

Author: github-actions[bot]

java-client/src/main/java/co/elastic/clients/transport/endpoints/EndpointBase.java

@@ -21,6 +21,7 @@
 
 import co.elastic.clients.elasticsearch._types.ErrorCause;
 import co.elastic.clients.elasticsearch._types.ErrorResponse;
+import co.elastic.clients.json.JsonData;
 import co.elastic.clients.json.JsonpDeserializer;
 import co.elastic.clients.json.JsonpDeserializerBase;
 import co.elastic.clients.json.JsonpMapper;
@@ -145,28 +146,43 @@ public JsonpDeserializer<ErrorResponse> errorDeserializer(int statusCode) {
             @Override
             public ErrorResponse deserialize(JsonParser parser, JsonpMapper mapper, JsonParser.Event event) {
                 ErrorResponse.Builder builder = new ErrorResponse.Builder();
+                ErrorCause.Builder errorCauseBuilder = new ErrorCause.Builder();
+                ErrorCause errorCause = null;
                 builder.status(statusCode);
                 while ((event = parser.next()) != JsonParser.Event.END_OBJECT) {
                     JsonpUtils.expectEvent(parser, JsonParser.Event.KEY_NAME, event);
                     switch (parser.getString()) {
                         case "error":
                             switch (event = parser.next()) {
                                 case VALUE_STRING:
-                                    builder.error(e -> e.reason(parser.getString()).type("http_status_" + statusCode));
+                                    errorCauseBuilder.reason(parser.getString()).type("http_status_" + statusCode);
                                     break;
                                 default:
                                     JsonpUtils.expectEvent(parser, JsonParser.Event.START_OBJECT, event);
-                                    builder.error(ErrorCause._DESERIALIZER.deserialize(parser, mapper, event));
+                                    errorCause = ErrorCause._DESERIALIZER.deserialize(parser, mapper, event);
                                     break;
                             }
                             break;
                         case "status":
                             JsonpUtils.expectNextEvent(parser, JsonParser.Event.VALUE_NUMBER);
                             builder.status(parser.getInt());
                             break;
+                        // could be additional information, deserializing it into error cause's metadata
+                        // for example 404 on GetAliasRequest
+                        default:
+                            String key = parser.getString();
+                            event = parser.next();
+                            JsonpUtils.expectEvent(parser, JsonParser.Event.START_OBJECT, event);
+                            errorCauseBuilder.metadata(key, JsonData._DESERIALIZER.deserialize(parser, mapper));
+                            break;
                     }
                 }
-
+                if (errorCause != null) {
+                    builder.error(errorCause);
+                }
+                else {
+                    builder.error(errorCauseBuilder.build());
+                }
                 return builder.build();
             }
         };