ES|QL: Make LOOKUP JOIN on aliases compatible with 8.19 (#128835)

Author: luigidellaquila

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

@@ -187,6 +187,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion INFERENCE_CUSTOM_SERVICE_ADDED_8_19 = def(8_841_0_39);
     public static final TransportVersion IDP_CUSTOM_SAML_ATTRIBUTES_ADDED_8_19 = def(8_841_0_40);
     public static final TransportVersion DATA_STREAM_OPTIONS_API_REMOVE_INCLUDE_DEFAULTS_8_19 = def(8_841_0_41);
+    public static final TransportVersion JOIN_ON_ALIASES_8_19 = def(8_841_0_42);
     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);

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/enrich/LookupFromIndexService.java

@@ -153,7 +153,8 @@ static TransportRequest readFrom(StreamInput in, BlockFactory blockFactory) thro
             ShardId shardId = new ShardId(in);
 
             String indexPattern;
-            if (in.getTransportVersion().onOrAfter(TransportVersions.JOIN_ON_ALIASES)) {
+            if (in.getTransportVersion().onOrAfter(TransportVersions.JOIN_ON_ALIASES)
+                || in.getTransportVersion().isPatchFrom(TransportVersions.JOIN_ON_ALIASES_8_19)) {
                 indexPattern = in.readString();
             } else {
                 indexPattern = shardId.getIndexName();
@@ -198,7 +199,8 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeString(sessionId);
             out.writeWriteable(shardId);
 
-            if (out.getTransportVersion().onOrAfter(TransportVersions.JOIN_ON_ALIASES)) {
+            if (out.getTransportVersion().onOrAfter(TransportVersions.JOIN_ON_ALIASES)
+                || out.getTransportVersion().isPatchFrom(TransportVersions.JOIN_ON_ALIASES_8_19)) {
                 out.writeString(indexPattern);
             } else if (indexPattern.equals(shardId.getIndexName()) == false) {
                 throw new EsqlIllegalArgumentException("Aliases and index patterns are not allowed for LOOKUP JOIN []", indexPattern);