Params should be single item of array type, not outer array of strings (#5037)

Signed-off-by: Simon Dudley <simon.dudley@consensys.net>

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineExchangeCapabilities.java

@@ -24,7 +24,6 @@ import org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.ExecutionEngin
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcResponse;
 import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcSuccessResponse;
 
-import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -52,10 +51,7 @@ public class EngineExchangeCapabilities extends ExecutionEngineJsonRpcMethod {
   public JsonRpcResponse syncResponse(final JsonRpcRequestContext requestContext) {
     engineCallListener.executionEngineCalled();
 
-    final List<String> remoteCapabilities =
-        Arrays.stream(requestContext.getRequest().getParams())
-            .map(String::valueOf)
-            .collect(Collectors.toList());
+    final String[] remoteCapabilities = requestContext.getRequiredParameter(0, String[].class);
     final Object reqId = requestContext.getRequest().getId();
 
     traceLambda(LOG, "received remote capabilities: {}", () -> remoteCapabilities);

ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineExchangeCapabilitiesTest.java

@@ -74,11 +74,13 @@ public class EngineExchangeCapabilitiesTest {
     verify(engineCallListener, times(1)).executionEngineCalled();
   }
 
-  private JsonRpcResponse resp(final List<String> params) {
+  private JsonRpcResponse resp(final List<String> capabilitiesParam) {
     return method.response(
         new JsonRpcRequestContext(
             new JsonRpcRequest(
-                "2.0", ENGINE_EXCHANGE_CAPABILITIES.getMethodName(), params.toArray())));
+                "2.0",
+                ENGINE_EXCHANGE_CAPABILITIES.getMethodName(),
+                new Object[] {capabilitiesParam})));
   }
 
   @SuppressWarnings("unchecked")

ethereum/referencetests/src/reference-test/external-resources

@@ -1 +1 @@
-Subproject commit 638da7ca7b2ca371ebb33d7d7d2562981aafd9b2
+Subproject commit 69c4c2a98dc8a712d4c6f5a817da4f21ff719006