2.7.x泛化调用: 客户端异步功能无法兼容低版本

[chpengzh]

• [x] I have searched the issues of this repository and believe that this is not a duplicate.
• [x] I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.7.6
• Operating System version: linux,macos
• Java version: 1.8

Steps to reproduce this issue

1. 使用2.5.6版本发布dubbo服务
2. 依照https://github.com/apache/dubbo/issues/3163 功能进行泛化调用，声明客户端异步化调用
3. Future 返回值中报错如下(method '$invokeAsync' not found)，错误来源于服务端；

Failed to invoke remote proxy method $invokeAsync to registry://10.179.84.162:2181/com.alibaba.dubbo.registry.RegistryService?application=htw-facade&application.name=htw-facade&dubbo=2.5.3-didi-24&export=dubbo%3A%2F%2F10.179.25.19%3A7778%2Fcom.d.h.f.a.s.F*Service%3Fanyhost%3Dtrue%26application%3Dh-f%26application.name%3Dh-f%26default.service.filter%3DBhBizProviderFilter%2CBhDLProviderFilter%2CBhMetricsProviderFilter%2CDubboProviderContextSwitchFilter%26default.threads%3D500%26default.token%3Dtrue%26dispatcher%3Dmessage%26dubbo%3D2.5.3-didi-24%26interface%3Dcom.d.h.f.a.s.F*Service%26methods%3DoutAuthAndSendVoucher%2CqueryCardRemainInfo%2ChealthData%2CgetCityConfigControlResult%2CgetTripEndPopResult%2CactivityConfig%2CqrCodeUrlAnalyze%2CoutAuthCheck%2CfindTripEndPopResult%26owner%3D*%26pid%3D34411%26revision%3D1.0.2%26side%3Dprovider%26threadname%3DnonCoreFacadeProvider%26threads%3D100%26timestamp%3D1597290687001%26version%3D1.0.0_stable&file=/h/x/h/dubboLocal.cache&owner=*&pid=34411&registry=zookeeper&timestamp=1597290687000, cause: Not found method \"$invokeAsync\" in class com.d.h.f.a.s.F*Service.

创建 ReferenceConfig 和调用相关代码

@Service
public class DubboGenericIntegrationServiceImpl implements DubboGenericIntegrationService {

    @Resource
    private ApplicationConfig applicationConfig;

    @Resource
    private List<RegistryConfig> registryConfigs;

    @Resource
    private ConsumerConfig consumerConfig;

    @Nonnull
    @Override
    public ReferenceConfig<GenericService> createReference(
            @Nonnull String serviceName,
            @Nonnull String version,
            boolean async
    ) {
        ReferenceConfig<GenericService> reference = new ReferenceConfig<>();
        reference.setInterface(serviceName);
        reference.setVersion(version);
        reference.setGeneric(Boolean.TRUE.toString());
        reference.setCheck(false);
        reference.setAsync(async);

        reference.setApplication(applicationConfig);
        reference.setRegistries(registryConfigs);
        reference.setConsumer(consumerConfig);
        return reference;
    }

    @Override
    public Object invokeSync(
            @Nonnull GenericService service,
            @Nonnull ProxyInvokeParam param
    ) {
        return service.$invoke(param.getMethod(), param.getParamTypes(), param.getParams());
    }

    @Override
    public CompletableFuture<Object> invokeASync(
            @Nonnull GenericService service,
            @Nonnull ProxyInvokeParam param
    ) {
        return service.$invokeAsync(param.getMethod(), param.getParamTypes(), param.getParams());
    }
}

[AlbumenJ]

For lower version is not support async generic call. It is impossible to make it work if consumer or provider not support it. Please try upgrade your provider version.