add nullaway to new module

Author: jaydeluca

instrumentation/spring/spring-cloud-gateway/spring-cloud-gateway-webmvc-4.3/javaagent/build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
   id("otel.javaagent-instrumentation")
+  id("otel.nullaway-conventions")
 }
 
 muzzle {

instrumentation/spring/spring-cloud-gateway/spring-cloud-gateway-webmvc-4.3/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spring/gateway/webmvc/v5_0/ServerRequestHelper.java

@@ -13,6 +13,7 @@
 import io.opentelemetry.instrumentation.api.instrumenter.LocalRootSpan;
 import io.opentelemetry.javaagent.instrumentation.spring.gateway.common.GatewayRouteHelper;
 import java.lang.reflect.Field;
+import javax.annotation.Nullable;
 import org.springframework.cloud.gateway.server.mvc.common.MvcUtils;
 import org.springframework.cloud.gateway.server.mvc.handler.GatewayDelegatingRouterFunction;
 import org.springframework.web.servlet.function.ServerRequest;
@@ -22,7 +23,7 @@
  * ServerRequest and adding it to spans.
  */
 public final class ServerRequestHelper {
-  private static final Field routeIdField;
+  @Nullable private static final Field routeIdField;
 
   static {
     Field routeIdField1 = null;
@@ -47,11 +48,6 @@ public static void extractAttributes(
       return;
     }
 
-    setRouteIdAttribute(gatewayRouterFunction, serverSpan);
-    setRouteUriAttribute(request, serverSpan);
-  }
-
-  private static void setRouteIdAttribute(Object gatewayRouterFunction, Span serverSpan) {
     try {
       String routeId = (String) routeIdField.get(gatewayRouterFunction);
       String convergedRouteId = GatewayRouteHelper.convergeRouteId(routeId);
@@ -61,9 +57,7 @@ private static void setRouteIdAttribute(Object gatewayRouterFunction, Span serve
     } catch (Exception e) {
       // Silently ignore
     }
-  }
 
-  private static void setRouteUriAttribute(ServerRequest request, Span serverSpan) {
     request
         .attribute(MvcUtils.GATEWAY_REQUEST_URL_ATTR)
         .ifPresent(uri -> serverSpan.setAttribute(ROUTE_URI_ATTRIBUTE, uri.toString()));