CNDB-14657: disable synthetic score for older versions in FeaturesVersionSupportTester

Author: driftx

test/distributed/org/apache/cassandra/distributed/test/sai/features/FeaturesVersionSupportTester.java

@@ -61,7 +61,16 @@ protected static void initCluster(Version version) throws IOException
 
         FeaturesVersionSupportTester.version = version;
         cluster = init(Cluster.build(2)
-                              .withInstanceInitializer((cl, n) -> BB.install(cl, n, version))
+                              .withInstanceInitializer((cl, n) -> {
+                                  // Disable synthetic score to ensure compatibility between ED and older versions.
+                                  // ED enables it by default but older versions don't support it.
+                                  // Note: In 5.0, Ordering.useSyntheticScore() uses CassandraRelevantProperties
+                                  // which caches values at class loading time, so we must set this property before
+                                  // the classes are loaded. In the main branch, Ordering uses System.getProperty() directly,
+                                  // which is why this workaround isn't needed there.
+                                  System.setProperty("cassandra.sai.ann_use_synthetic_score", "false");
+                                  BB.install(cl, n, version);
+                              })
                               .withConfig(config -> config.with(GOSSIP).with(NETWORK))
                               .start(), 1);