Adding transport version check

Author: jonathan-buttner

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -196,6 +196,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ML_INFERENCE_ELASTIC_RERANK_ADDED_8_19 = def(8_841_0_48);
     public static final TransportVersion NONE_CHUNKING_STRATEGY_8_19 = def(8_841_0_49);
     public static final TransportVersion IDP_CUSTOM_SAML_ATTRIBUTES_ALLOW_LIST_8_19 = def(8_841_0_50);
+    public static final TransportVersion ML_INFERENCE_CUSTOM_SERVICE_REMOVE_ERROR_PARSING_8_19 = def(8_841_0_51);
     public static final TransportVersion V_9_0_0 = def(9_000_0_09);
     public static final TransportVersion INITIAL_ELASTICSEARCH_9_0_1 = def(9_000_0_10);
     public static final TransportVersion INITIAL_ELASTICSEARCH_9_0_2 = def(9_000_0_11);
@@ -298,6 +299,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion HEAP_USAGE_IN_CLUSTER_INFO = def(9_096_0_00);
     public static final TransportVersion NONE_CHUNKING_STRATEGY = def(9_097_0_00);
     public static final TransportVersion PROJECT_DELETION_GLOBAL_BLOCK = def(9_098_0_00);
+    public static final TransportVersion ML_INFERENCE_CUSTOM_SERVICE_REMOVE_ERROR_PARSING = def(9_099_0_00);
 
     /*
      * STOP! READ THIS FIRST! No, really,

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/services/custom/CustomServiceSettings.java

@@ -223,6 +223,12 @@ public CustomServiceSettings(StreamInput in) throws IOException {
         requestContentString = in.readString();
         responseJsonParser = in.readNamedWriteable(CustomResponseParser.class);
         rateLimitSettings = new RateLimitSettings(in);
+        if (in.getTransportVersion().before(TransportVersions.ML_INFERENCE_CUSTOM_SERVICE_REMOVE_ERROR_PARSING)
+            && in.getTransportVersion().isPatchFrom(TransportVersions.ML_INFERENCE_CUSTOM_SERVICE_REMOVE_ERROR_PARSING_8_19) == false) {
+            // Read the error parsing fields for backwards compatibility
+            in.readString();
+            in.readString();
+        }
     }
 
     @Override
@@ -337,6 +343,12 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeString(requestContentString);
         out.writeNamedWriteable(responseJsonParser);
         rateLimitSettings.writeTo(out);
+        if (out.getTransportVersion().before(TransportVersions.ML_INFERENCE_CUSTOM_SERVICE_REMOVE_ERROR_PARSING)
+            && out.getTransportVersion().isPatchFrom(TransportVersions.ML_INFERENCE_CUSTOM_SERVICE_REMOVE_ERROR_PARSING_8_19) == false) {
+            // Write empty strings for backwards compatibility for the error parsing fields
+            out.writeString("");
+            out.writeString("");
+        }
     }
 
     @Override