[ref-counts] DualRefCounted orphanability is different to Orphanable orphanability (#36194)

Previously we wrote `DualRefCounted : public Orphanable`, but this is wrong: `Orphan`-ing is a private implementation detail to `DualRefCounted`, but a public interface to `Orphanable`.

This bug means that it's possible to write `OrphanablePtr<T>` when `T` is derived from `DualRefCounted`, leading to hard to diagnose bugs - especially when moving a previously `Orphanable` type to be `DualRefCounted`.

This change removes the inheritance from `Orphanable`, and instead adds an overridable method `Orphaned` that implementors of `DualRefCounted` can implement.

In this way we get:
* compiler errors if someone chooses to write `OrphanablePtr` for one of these types
* compiler errors if someone implements `Orphan()` instead of `Orphaned()` in the wrong place (or vice versa)

Closes #36194

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/36194 from ctiller:orf b96b831a96
PiperOrigin-RevId: 620916632

src/core/client_channel/client_channel_filter.cc

@@ -684,7 +684,7 @@ class ClientChannelFilter::SubchannelWrapper : public SubchannelInterface {
     GRPC_CHANNEL_STACK_UNREF(chand_->owning_stack_, "SubchannelWrapper");
   }
 
-  void Orphan() override {
+  void Orphaned() override {
     if (!IsWorkSerializerDispatchEnabled()) return;
     // Make sure we clean up the channel's subchannel maps inside the
     // WorkSerializer.

src/core/client_channel/subchannel.cc

@@ -619,7 +619,7 @@ void Subchannel::ResetBackoff() {
   work_serializer_.DrainQueue();
 }
 
-void Subchannel::Orphan() {
+void Subchannel::Orphaned() {
   // The subchannel_pool is only used once here in this subchannel, so the
   // access can be outside of the lock.
   if (subchannel_pool_ != nullptr) {

src/core/client_channel/subchannel.h

@@ -250,9 +250,6 @@ class Subchannel : public DualRefCounted<Subchannel> {
   // Resets the connection backoff of the subchannel.
   void ResetBackoff() ABSL_LOCKS_EXCLUDED(mu_);
 
-  // Tears down any existing connection, and arranges for destruction
-  void Orphan() override ABSL_LOCKS_EXCLUDED(mu_);
-
   // Access to data producer map.
   // We do not hold refs to the data producer; the implementation is
   // expected to register itself upon construction and remove itself
@@ -277,6 +274,9 @@ class Subchannel : public DualRefCounted<Subchannel> {
   }
 
  private:
+  // Tears down any existing connection, and arranges for destruction
+  void Orphaned() override ABSL_LOCKS_EXCLUDED(mu_);
+
   // A linked list of ConnectivityStateWatcherInterfaces that are monitoring
   // the subchannel's state.
   class ConnectivityStateWatcherList {

src/core/ext/xds/xds_client.cc

@@ -485,7 +485,7 @@ XdsClient::XdsChannel::~XdsChannel() {
 // use a ABSL_EXCLUSIVE_LOCKS_REQUIRED annotation, because Orphan() will be
 // called from DualRefCounted::Unref, which cannot have a lock annotation for
 // a lock in this subclass.
-void XdsClient::XdsChannel::Orphan() ABSL_NO_THREAD_SAFETY_ANALYSIS {
+void XdsClient::XdsChannel::Orphaned() ABSL_NO_THREAD_SAFETY_ANALYSIS {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_xds_client_trace)) {
     gpr_log(GPR_INFO, "[xds_client %p] orphaning xds channel %p for server %s",
             xds_client(), this, server_.server_uri().c_str());
@@ -1533,7 +1533,7 @@ XdsClient::~XdsClient() {
   }
 }
 
-void XdsClient::Orphan() {
+void XdsClient::Orphaned() {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_xds_client_trace)) {
     gpr_log(GPR_INFO, "[xds_client %p] shutting down xds client", this);
   }

src/core/ext/xds/xds_client.h

@@ -104,8 +104,6 @@ class XdsClient : public DualRefCounted<XdsClient> {
     return transport_factory_.get();
   }
 
-  void Orphan() override;
-
   // Start and cancel watch for a resource.
   //
   // The XdsClient takes ownership of the watcher, but the caller may
@@ -161,6 +159,8 @@ class XdsClient : public DualRefCounted<XdsClient> {
   }
 
  protected:
+  void Orphaned() override;
+
   Mutex* mu() ABSL_LOCK_RETURNED(&mu_) { return &mu_; }
 
   // Dumps the active xDS config to the provided
@@ -220,8 +220,6 @@ class XdsClient : public DualRefCounted<XdsClient> {
                const XdsBootstrap::XdsServer& server);
     ~XdsChannel() override;
 
-    void Orphan() override;
-
     XdsClient* xds_client() const { return xds_client_.get(); }
     AdsCall* ads_call() const;
     LrsCall* lrs_call() const;
@@ -246,6 +244,8 @@ class XdsClient : public DualRefCounted<XdsClient> {
     absl::string_view server_uri() const { return server_.server_uri(); }
 
    private:
+    void Orphaned() override;
+
     void OnConnectivityFailure(absl::Status status);
 
     // Enqueues error notifications to watchers.  Caller must drain

src/core/ext/xds/xds_client_grpc.cc

@@ -305,9 +305,9 @@ GrpcXdsClient::GrpcXdsClient(
           },
           {kMetricConnected, kMetricResources})) {}
 
-void GrpcXdsClient::Orphan() {
+void GrpcXdsClient::Orphaned() {
   registered_metric_callback_.reset();
-  XdsClient::Orphan();
+  XdsClient::Orphaned();
   MutexLock lock(g_mu);
   auto it = g_xds_client_map->find(key_);
   if (it != g_xds_client_map->end() && it->second == this) {

src/core/ext/xds/xds_client_grpc.h

@@ -66,8 +66,6 @@ class GrpcXdsClient : public XdsClient {
                 const ChannelArgs& args,
                 OrphanablePtr<XdsTransportFactory> transport_factory);
 
-  void Orphan() override;
-
   // Helpers for encoding the XdsClient object in channel args.
   static absl::string_view ChannelArgName() {
     return GRPC_ARG_NO_SUBCHANNEL_PREFIX "xds_client";
@@ -91,6 +89,7 @@ class GrpcXdsClient : public XdsClient {
   class MetricsReporter;
 
   void ReportCallbackMetrics(CallbackMetricReporter& reporter);
+  void Orphaned() override;
 
   std::string key_;
   OrphanablePtr<CertificateProviderStore> certificate_provider_store_;

src/core/ext/xds/xds_server_config_fetcher.cc

@@ -215,8 +215,6 @@ class XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager
   absl::StatusOr<ChannelArgs> UpdateChannelArgsForConnection(
       const ChannelArgs& args, grpc_endpoint* tcp) override;
 
-  void Orphan() override;
-
   // Invoked by ListenerWatcher to start fetching referenced RDS resources.
   void StartRdsWatch(RefCountedPtr<ListenerWatcher> listener_watcher)
       ABSL_EXCLUSIVE_LOCKS_REQUIRED(&ListenerWatcher::mu_);
@@ -246,6 +244,7 @@ class XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager
   absl::StatusOr<RefCountedPtr<XdsCertificateProvider>>
   CreateOrGetXdsCertificateProviderFromFilterChainData(
       const XdsListenerResource::FilterChainData* filter_chain);
+  void Orphaned() override;
 
   // Helper functions invoked by RouteConfigWatcher when there are updates to
   // RDS resources.
@@ -415,11 +414,11 @@ class XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
         static_resource_.value(), http_filters_);
   }
 
-  void Orphan() override {}
-
   void CancelWatch() override { watcher_.reset(); }
 
  private:
+  void Orphaned() override {}
+
   RefCountedPtr<GrpcXdsClient> xds_client_;
   absl::StatusOr<std::shared_ptr<const XdsRouteConfigResource>>
       static_resource_;
@@ -449,8 +448,6 @@ class XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
     xds_client_.reset(DEBUG_LOCATION, "DynamicXdsServerConfigSelectorProvider");
   }
 
-  void Orphan() override;
-
   absl::StatusOr<RefCountedPtr<ServerConfigSelector>> Watch(
       std::unique_ptr<ServerConfigSelectorProvider::ServerConfigSelectorWatcher>
           watcher) override;
@@ -459,6 +456,7 @@ class XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
  private:
   class RouteConfigWatcher;
 
+  void Orphaned() override;
   void OnRouteConfigChanged(
       std::shared_ptr<const XdsRouteConfigResource> rds_update);
   void OnError(absl::Status status);
@@ -783,7 +781,7 @@ void XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
 }
 
 void XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
-    Orphan() {
+    Orphaned() {
   MutexLock lock(&mu_);
   // Cancel the RDS watches to clear up the weak refs
   for (const auto& entry : rds_map_) {
@@ -1281,7 +1279,7 @@ XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
 }
 
 void XdsServerConfigFetcher::ListenerWatcher::FilterChainMatchManager::
-    DynamicXdsServerConfigSelectorProvider::Orphan() {
+    DynamicXdsServerConfigSelectorProvider::Orphaned() {
   XdsRouteConfigResourceType::CancelWatch(xds_client_.get(), resource_name_,
                                           route_config_watcher_,
                                           false /* delay_unsubscription */);

src/core/lib/gprpp/dual_ref_counted.h

@@ -39,19 +39,19 @@ namespace grpc_core {
 //
 // Each class of refs can be incremented and decremented independently.
 // Objects start with 1 strong ref and 0 weak refs at instantiation.
-// When the strong refcount reaches 0, the object's Orphan() method is called.
+// When the strong refcount reaches 0, the object's Orphaned() method is called.
 // When the weak refcount reaches 0, the object is destroyed.
 //
 // This will be used by CRTP (curiously-recurring template pattern), e.g.:
 //   class MyClass : public RefCounted<MyClass> { ... };
 template <typename Child>
-class DualRefCounted : public Orphanable {
+class DualRefCounted {
  public:
   // Not copyable nor movable.
   DualRefCounted(const DualRefCounted&) = delete;
   DualRefCounted& operator=(const DualRefCounted&) = delete;
 
-  ~DualRefCounted() override = default;
+  virtual ~DualRefCounted() = default;
 
   GRPC_MUST_USE_RESULT RefCountedPtr<Child> Ref() {
     IncrementRefCount();
@@ -93,7 +93,7 @@ class DualRefCounted : public Orphanable {
     GPR_ASSERT(strong_refs > 0);
 #endif
     if (GPR_UNLIKELY(strong_refs == 1)) {
-      Orphan();
+      Orphaned();
     }
     // Now drop the weak ref.
     WeakUnref();
@@ -116,7 +116,7 @@ class DualRefCounted : public Orphanable {
     (void)reason;
 #endif
     if (GPR_UNLIKELY(strong_refs == 1)) {
-      Orphan();
+      Orphaned();
     }
     // Now drop the weak ref.
     WeakUnref(location, reason);
@@ -257,6 +257,9 @@ class DualRefCounted : public Orphanable {
         refs_(MakeRefPair(initial_refcount, 0)) {
   }
 
+  // Ref count has dropped to zero, so the object is now orphaned.
+  virtual void Orphaned() = 0;
+
  private:
   // Allow RefCountedPtr<> to access IncrementRefCount().
   template <typename T>

src/core/lib/security/authorization/grpc_authorization_policy_provider.cc

@@ -179,7 +179,7 @@ absl::Status FileWatcherAuthorizationPolicyProvider::ForceUpdate() {
   return absl::OkStatus();
 }
 
-void FileWatcherAuthorizationPolicyProvider::Orphan() {
+void FileWatcherAuthorizationPolicyProvider::Orphaned() {
   gpr_event_set(&shutdown_event_, reinterpret_cast<void*>(1));
   if (refresh_thread_ != nullptr) {
     refresh_thread_->Join();

src/core/lib/security/authorization/grpc_authorization_policy_provider.h

@@ -56,7 +56,7 @@ class StaticDataAuthorizationPolicyProvider
     return {allow_engine_, deny_engine_};
   }
 
-  void Orphan() override {}
+  void Orphaned() override {}
 
  private:
   RefCountedPtr<AuthorizationEngine> allow_engine_;
@@ -87,7 +87,7 @@ class FileWatcherAuthorizationPolicyProvider
   void SetCallbackForTesting(
       std::function<void(bool contents_changed, absl::Status Status)> cb);
 
-  void Orphan() override;
+  void Orphaned() override;
 
   AuthorizationEngines engines() override {
     MutexLock lock(&mu_);

src/core/lib/surface/legacy_channel.cc

@@ -309,7 +309,7 @@ class LegacyChannel::StateWatcher : public DualRefCounted<StateWatcher> {
   }
 
   // Invoked when both strong refs are released.
-  void Orphan() override {
+  void Orphaned() override {
     WeakRef().release();  // Take a weak ref until completion is finished.
     grpc_error_handle error =
         timer_fired_

src/core/load_balancing/grpclb/grpclb.cc

@@ -140,8 +140,8 @@
 #include "src/core/load_balancing/lb_policy_factory.h"
 #include "src/core/load_balancing/lb_policy_registry.h"
 #include "src/core/load_balancing/subchannel_interface.h"
-#include "src/core/resolver/fake/fake_resolver.h"
 #include "src/core/resolver/endpoint_addresses.h"
+#include "src/core/resolver/fake/fake_resolver.h"
 #include "src/core/resolver/resolver.h"
 
 #define GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS 1
@@ -317,7 +317,11 @@ class GrpcLb : public LoadBalancingPolicy {
           lb_token_(std::move(lb_token)),
           client_stats_(std::move(client_stats)) {}
 
-    void Orphan() override {
+    const std::string& lb_token() const { return lb_token_; }
+    GrpcLbClientStats* client_stats() const { return client_stats_.get(); }
+
+   private:
+    void Orphaned() override {
       if (!IsWorkSerializerDispatchEnabled()) {
         if (!lb_policy_->shutting_down_) {
           lb_policy_->CacheDeletedSubchannelLocked(wrapped_subchannel());
@@ -334,10 +338,6 @@ class GrpcLb : public LoadBalancingPolicy {
           DEBUG_LOCATION);
     }
 
-    const std::string& lb_token() const { return lb_token_; }
-    GrpcLbClientStats* client_stats() const { return client_stats_.get(); }
-
-   private:
     RefCountedPtr<GrpcLb> lb_policy_;
     std::string lb_token_;
     RefCountedPtr<GrpcLbClientStats> client_stats_;
@@ -1627,10 +1627,9 @@ absl::Status GrpcLb::UpdateBalancerChannelLocked() {
   if (lb_channel_ == nullptr) {
     std::string uri_str =
         absl::StrCat("fake:///", channel_control_helper()->GetAuthority());
-    lb_channel_.reset(
-        Channel::FromC(
-            grpc_channel_create(uri_str.c_str(), channel_credentials.get(),
-                                lb_channel_args.ToC().get())));
+    lb_channel_.reset(Channel::FromC(
+        grpc_channel_create(uri_str.c_str(), channel_credentials.get(),
+                            lb_channel_args.ToC().get())));
     GPR_ASSERT(lb_channel_ != nullptr);
     // Set up channelz linkage.
     channelz::ChannelNode* child_channelz_node = lb_channel_->channelz_node();

src/core/load_balancing/health_check_client.cc

@@ -42,7 +42,6 @@
 
 #include "src/core/client_channel/client_channel_channelz.h"
 #include "src/core/client_channel/client_channel_internal.h"
-#include "src/core/load_balancing/health_check_client_internal.h"
 #include "src/core/client_channel/subchannel.h"
 #include "src/core/client_channel/subchannel_stream_client.h"
 #include "src/core/lib/address_utils/sockaddr_utils.h"
@@ -59,9 +58,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/iomgr_fwd.h"
 #include "src/core/lib/iomgr/pollset_set.h"
-#include "src/core/load_balancing/subchannel_interface.h"
 #include "src/core/lib/slice/slice.h"
 #include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/load_balancing/health_check_client_internal.h"
+#include "src/core/load_balancing/subchannel_interface.h"
 #include "src/proto/grpc/health/v1/health.upb.h"
 
 namespace grpc_core {
@@ -362,7 +362,7 @@ void HealthProducer::Start(RefCountedPtr<Subchannel> subchannel) {
   subchannel_->WatchConnectivityState(std::move(connectivity_watcher));
 }
 
-void HealthProducer::Orphan() {
+void HealthProducer::Orphaned() {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_health_check_client_trace)) {
     gpr_log(GPR_INFO, "HealthProducer %p: shutting down", this);
   }

src/core/load_balancing/health_check_client_internal.h

@@ -59,8 +59,6 @@ class HealthProducer : public Subchannel::DataProducerInterface {
 
   void Start(RefCountedPtr<Subchannel> subchannel);
 
-  void Orphan() override;
-
   static UniqueTypeName Type() {
     static UniqueTypeName::Factory kFactory("health_check");
     return kFactory.Create();
@@ -139,6 +137,7 @@ class HealthProducer : public Subchannel::DataProducerInterface {
   // Handles a connectivity state change on the subchannel.
   void OnConnectivityStateChange(grpc_connectivity_state state,
                                  const absl::Status& status);
+  void Orphaned() override;
 
   RefCountedPtr<Subchannel> subchannel_;
   ConnectivityWatcher* connectivity_watcher_;

src/core/load_balancing/lb_policy.h

@@ -38,7 +38,6 @@
 #include <grpc/grpc.h>
 #include <grpc/impl/connectivity_state.h>
 
-#include "src/core/load_balancing/backend_metric_data.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/metrics.h"
 #include "src/core/lib/debug/trace.h"
@@ -51,6 +50,7 @@
 #include "src/core/lib/gprpp/work_serializer.h"
 #include "src/core/lib/iomgr/iomgr_fwd.h"
 #include "src/core/lib/iomgr/resolved_address.h"
+#include "src/core/load_balancing/backend_metric_data.h"
 #include "src/core/load_balancing/subchannel_interface.h"
 #include "src/core/resolver/endpoint_addresses.h"
 
@@ -275,7 +275,8 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> {
 
     virtual PickResult Pick(PickArgs args) = 0;
 
-    void Orphan() override {}
+   protected:
+    void Orphaned() override {}
   };
 
   /// A proxy object implemented by the client channel and used by the

src/core/load_balancing/oob_backend_metric.cc

@@ -221,7 +221,7 @@ void OrcaProducer::Start(RefCountedPtr<Subchannel> subchannel) {
   subchannel_->WatchConnectivityState(std::move(connectivity_watcher));
 }
 
-void OrcaProducer::Orphan() {
+void OrcaProducer::Orphaned() {
   {
     MutexLock lock(&mu_);
     stream_client_.reset();

src/core/load_balancing/oob_backend_metric_internal.h

@@ -28,8 +28,6 @@
 
 #include <grpc/impl/connectivity_state.h>
 
-#include "src/core/load_balancing/backend_metric_data.h"
-#include "src/core/load_balancing/oob_backend_metric.h"
 #include "src/core/client_channel/subchannel.h"
 #include "src/core/client_channel/subchannel_interface_internal.h"
 #include "src/core/client_channel/subchannel_stream_client.h"
@@ -38,6 +36,8 @@
 #include "src/core/lib/gprpp/sync.h"
 #include "src/core/lib/gprpp/time.h"
 #include "src/core/lib/gprpp/unique_type_name.h"
+#include "src/core/load_balancing/backend_metric_data.h"
+#include "src/core/load_balancing/oob_backend_metric.h"
 
 namespace grpc_core {
 
@@ -50,8 +50,6 @@ class OrcaProducer : public Subchannel::DataProducerInterface {
  public:
   void Start(RefCountedPtr<Subchannel> subchannel);
 
-  void Orphan() override;
-
   static UniqueTypeName Type() {
     static UniqueTypeName::Factory kFactory("orca");
     return kFactory.Create();
@@ -67,6 +65,8 @@ class OrcaProducer : public Subchannel::DataProducerInterface {
   class ConnectivityWatcher;
   class OrcaStreamEventHandler;
 
+  void Orphaned() override;
+
   // Returns the minimum requested reporting interval across all watchers.
   Duration GetMinIntervalLocked() const ABSL_EXCLUSIVE_LOCKS_REQUIRED(&mu_);
 

src/core/load_balancing/outlier_detection/outlier_detection.cc

@@ -44,8 +44,6 @@
 #include <grpc/impl/connectivity_state.h>
 #include <grpc/support/log.h>
 
-#include "src/core/load_balancing/child_policy_handler.h"
-#include "src/core/load_balancing/health_check_client_internal.h"
 #include "src/core/client_channel/subchannel_interface_internal.h"
 #include "src/core/lib/address_utils/sockaddr_utils.h"
 #include "src/core/lib/channel/channel_args.h"
@@ -66,7 +64,9 @@
 #include "src/core/lib/iomgr/resolved_address.h"
 #include "src/core/lib/json/json.h"
 #include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/load_balancing/child_policy_handler.h"
 #include "src/core/load_balancing/delegating_helper.h"
+#include "src/core/load_balancing/health_check_client_internal.h"
 #include "src/core/load_balancing/lb_policy.h"
 #include "src/core/load_balancing/lb_policy_factory.h"
 #include "src/core/load_balancing/lb_policy_registry.h"
@@ -144,22 +144,6 @@ class OutlierDetectionLb : public LoadBalancingPolicy {
       }
     }
 
-    void Orphan() override {
-      if (!IsWorkSerializerDispatchEnabled()) {
-        if (subchannel_state_ != nullptr) {
-          subchannel_state_->RemoveSubchannel(this);
-        }
-        return;
-      }
-      work_serializer_->Run(
-          [self = WeakRefAsSubclass<SubchannelWrapper>()]() {
-            if (self->subchannel_state_ != nullptr) {
-              self->subchannel_state_->RemoveSubchannel(self.get());
-            }
-          },
-          DEBUG_LOCATION);
-    }
-
     void Eject();
 
     void Uneject();
@@ -228,6 +212,22 @@ class OutlierDetectionLb : public LoadBalancingPolicy {
       bool ejected_;
     };
 
+    void Orphaned() override {
+      if (!IsWorkSerializerDispatchEnabled()) {
+        if (subchannel_state_ != nullptr) {
+          subchannel_state_->RemoveSubchannel(this);
+        }
+        return;
+      }
+      work_serializer_->Run(
+          [self = WeakRefAsSubclass<SubchannelWrapper>()]() {
+            if (self->subchannel_state_ != nullptr) {
+              self->subchannel_state_->RemoveSubchannel(self.get());
+            }
+          },
+          DEBUG_LOCATION);
+    }
+
     std::shared_ptr<WorkSerializer> work_serializer_;
     RefCountedPtr<SubchannelState> subchannel_state_;
     bool ejected_ = false;

src/core/load_balancing/rls/rls.cc

@@ -67,7 +67,6 @@
 #include <grpc/support/log.h>
 
 #include "src/core/client_channel/client_channel_filter.h"
-#include "src/core/load_balancing/child_policy_handler.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/channelz.h"
@@ -94,19 +93,20 @@
 #include "src/core/lib/json/json_object_loader.h"
 #include "src/core/lib/json/json_writer.h"
 #include "src/core/lib/security/credentials/fake/fake_credentials.h"
-#include "src/core/service_config/service_config_impl.h"
 #include "src/core/lib/slice/slice.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/error_utils.h"
+#include "src/core/load_balancing/child_policy_handler.h"
 #include "src/core/load_balancing/delegating_helper.h"
 #include "src/core/load_balancing/lb_policy.h"
 #include "src/core/load_balancing/lb_policy_factory.h"
 #include "src/core/load_balancing/lb_policy_registry.h"
 #include "src/core/resolver/endpoint_addresses.h"
 #include "src/core/resolver/resolver_registry.h"
+#include "src/core/service_config/service_config_impl.h"
 #include "src/proto/grpc/lookup/v1/rls.upb.h"
 
 using ::grpc_event_engine::experimental::EventEngine;
@@ -127,8 +127,7 @@ constexpr absl::string_view kMetricLabelPickResult = "grpc.lb.pick_result";
 
 const auto kMetricCacheSize =
     GlobalInstrumentsRegistry::RegisterCallbackInt64Gauge(
-        "grpc.lb.rls.cache_size", "EXPERIMENTAL.  Size of the RLS cache.",
-        "By",
+        "grpc.lb.rls.cache_size", "EXPERIMENTAL.  Size of the RLS cache.", "By",
         {kMetricLabelTarget, kMetricLabelRlsServerTarget,
          kMetricLabelRlsInstanceUuid},
         {}, false);
@@ -167,8 +166,7 @@ const auto kMetricFailedPicks =
         "grpc.lb.rls.failed_picks",
         "EXPERIMENTAL.  Number of LB picks failed due to either a failed RLS "
         "request or the RLS channel being throttled.",
-        "{pick}", {kMetricLabelTarget, kMetricLabelRlsServerTarget}, {},
-        false);
+        "{pick}", {kMetricLabelTarget, kMetricLabelRlsServerTarget}, {}, false);
 
 constexpr absl::string_view kRls = "rls_experimental";
 const char kGrpc[] = "grpc";
@@ -329,11 +327,6 @@ class RlsLb : public LoadBalancingPolicy {
    public:
     ChildPolicyWrapper(RefCountedPtr<RlsLb> lb_policy, std::string target);
 
-    // Note: We are forced to disable lock analysis here because
-    // Orphan() is called by OrphanablePtr<>, which cannot have lock
-    // annotations for this particular caller.
-    void Orphan() override ABSL_NO_THREAD_SAFETY_ANALYSIS;
-
     const std::string& target() const { return target_; }
 
     PickResult Pick(PickArgs args) ABSL_EXCLUSIVE_LOCKS_REQUIRED(&RlsLb::mu_) {
@@ -401,6 +394,11 @@ class RlsLb : public LoadBalancingPolicy {
       WeakRefCountedPtr<ChildPolicyWrapper> wrapper_;
     };
 
+    // Note: We are forced to disable lock analysis here because
+    // Orphan() is called by Unref() which is called by RefCountedPtr<>, which
+    // cannot have lock annotations for this particular caller.
+    void Orphaned() override ABSL_NO_THREAD_SAFETY_ANALYSIS;
+
     RefCountedPtr<RlsLb> lb_policy_;
     std::string target_;
 
@@ -804,7 +802,7 @@ RlsLb::ChildPolicyWrapper::ChildPolicyWrapper(RefCountedPtr<RlsLb> lb_policy,
   lb_policy_->child_policy_map_.emplace(target_, this);
 }
 
-void RlsLb::ChildPolicyWrapper::Orphan() {
+void RlsLb::ChildPolicyWrapper::Orphaned() {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_rls_trace)) {
     gpr_log(GPR_INFO, "[rlslb %p] ChildPolicyWrapper=%p [%s]: shutdown",
             lb_policy_.get(), this, target_.c_str());
@@ -1092,8 +1090,8 @@ LoadBalancingPolicy::PickResult RlsLb::Picker::Pick(PickArgs args) {
     if (entry->backoff_time() >= now) {
       return PickFromDefaultTargetOrFail(
           "RLS call in backoff", args,
-          absl::UnavailableError(absl::StrCat(
-              "RLS request failed: ", entry->status().ToString())));
+          absl::UnavailableError(absl::StrCat("RLS request failed: ",
+                                              entry->status().ToString())));
     }
   }
   // RLS call pending.  Queue the pick.
@@ -1112,8 +1110,8 @@ LoadBalancingPolicy::PickResult RlsLb::Picker::PickFromDefaultTargetOrFail(
               lb_policy_.get(), this, reason);
     }
     auto pick_result = default_child_policy_->Pick(args);
-    lb_policy_->MaybeExportPickCount(
-        kMetricDefaultTargetPicks, config_->default_target(), pick_result);
+    lb_policy_->MaybeExportPickCount(kMetricDefaultTargetPicks,
+                                     config_->default_target(), pick_result);
     return pick_result;
   }
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_rls_trace)) {
@@ -1122,10 +1120,10 @@ LoadBalancingPolicy::PickResult RlsLb::Picker::PickFromDefaultTargetOrFail(
   }
   auto& stats_plugins =
       lb_policy_->channel_control_helper()->GetStatsPluginGroup();
-  stats_plugins.AddCounter(
-      kMetricFailedPicks, 1,
-      {lb_policy_->channel_control_helper()->GetTarget(),
-       config_->lookup_service()}, {});
+  stats_plugins.AddCounter(kMetricFailedPicks, 1,
+                           {lb_policy_->channel_control_helper()->GetTarget(),
+                            config_->lookup_service()},
+                           {});
   return PickResult::Fail(std::move(status));
 }
 
@@ -1271,8 +1269,8 @@ LoadBalancingPolicy::PickResult RlsLb::Cache::Entry::Pick(PickArgs args) {
     args.initial_metadata->Add(kRlsHeaderKey, copied_header_data);
   }
   auto pick_result = child_policy_wrapper->Pick(args);
-  lb_policy_->MaybeExportPickCount(
-      kMetricTargetPicks, child_policy_wrapper->target(), pick_result);
+  lb_policy_->MaybeExportPickCount(kMetricTargetPicks,
+                                   child_policy_wrapper->target(), pick_result);
   return pick_result;
 }
 
@@ -1453,16 +1451,16 @@ void RlsLb::Cache::Shutdown() {
 }
 
 void RlsLb::Cache::ReportMetricsLocked(CallbackMetricReporter& reporter) {
-  reporter.Report(kMetricCacheSize, size_,
-                  {lb_policy_->channel_control_helper()->GetTarget(),
-                   lb_policy_->config_->lookup_service(),
-                   lb_policy_->instance_uuid_},
-                  {});
-  reporter.Report(kMetricCacheEntries, map_.size(),
-                  {lb_policy_->channel_control_helper()->GetTarget(),
-                   lb_policy_->config_->lookup_service(),
-                   lb_policy_->instance_uuid_},
-                  {});
+  reporter.Report(
+      kMetricCacheSize, size_,
+      {lb_policy_->channel_control_helper()->GetTarget(),
+       lb_policy_->config_->lookup_service(), lb_policy_->instance_uuid_},
+      {});
+  reporter.Report(
+      kMetricCacheEntries, map_.size(),
+      {lb_policy_->channel_control_helper()->GetTarget(),
+       lb_policy_->config_->lookup_service(), lb_policy_->instance_uuid_},
+      {});
 }
 
 void RlsLb::Cache::StartCleanupTimer() {
@@ -1630,10 +1628,9 @@ RlsLb::RlsChannel::RlsChannel(RefCountedPtr<RlsLb> lb_policy)
     args = args.Set(GRPC_ARG_SERVICE_CONFIG, service_config)
                .Set(GRPC_ARG_SERVICE_CONFIG_DISABLE_RESOLUTION, 1);
   }
-  channel_.reset(
-      Channel::FromC(
-          grpc_channel_create(lb_policy_->config_->lookup_service().c_str(),
-                              creds.get(), args.ToC().get())));
+  channel_.reset(Channel::FromC(
+      grpc_channel_create(lb_policy_->config_->lookup_service().c_str(),
+                          creds.get(), args.ToC().get())));
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_rls_trace)) {
     gpr_log(GPR_INFO, "[rlslb %p] RlsChannel=%p: created channel %p for %s",
             lb_policy_.get(), this, channel_.get(),
@@ -1947,9 +1944,9 @@ std::string GenerateUUID() {
 
 RlsLb::RlsLb(Args args)
     : LoadBalancingPolicy(std::move(args)),
-      instance_uuid_(
-          channel_args().GetOwnedString(GRPC_ARG_TEST_ONLY_RLS_INSTANCE_ID)
-              .value_or(GenerateUUID())),
+      instance_uuid_(channel_args()
+                         .GetOwnedString(GRPC_ARG_TEST_ONLY_RLS_INSTANCE_ID)
+                         .value_or(GenerateUUID())),
       cache_(this),
       registered_metric_callback_(
           channel_control_helper()->GetStatsPluginGroup().RegisterCallback(
@@ -2229,26 +2226,20 @@ void RlsLb::UpdatePickerLocked() {
 void RlsLb::MaybeExportPickCount(
     GlobalInstrumentsRegistry::GlobalUInt64CounterHandle handle,
     absl::string_view target, const PickResult& pick_result) {
-  absl::string_view pick_result_string =
-      Match(pick_result.result,
-            [](const LoadBalancingPolicy::PickResult::Complete&) {
-              return "complete";
-            },
-            [](const LoadBalancingPolicy::PickResult::Queue&) {
-              return "";
-            },
-            [](const LoadBalancingPolicy::PickResult::Fail&) {
-              return "fail";
-            },
-            [](const LoadBalancingPolicy::PickResult::Drop&) {
-              return "drop";
-            });
+  absl::string_view pick_result_string = Match(
+      pick_result.result,
+      [](const LoadBalancingPolicy::PickResult::Complete&) {
+        return "complete";
+      },
+      [](const LoadBalancingPolicy::PickResult::Queue&) { return ""; },
+      [](const LoadBalancingPolicy::PickResult::Fail&) { return "fail"; },
+      [](const LoadBalancingPolicy::PickResult::Drop&) { return "drop"; });
   if (pick_result_string.empty()) return;  // Don't report queued picks.
   auto& stats_plugins = channel_control_helper()->GetStatsPluginGroup();
   stats_plugins.AddCounter(
       handle, 1,
-      {channel_control_helper()->GetTarget(), config_->lookup_service(),
-       target, pick_result_string},
+      {channel_control_helper()->GetTarget(), config_->lookup_service(), target,
+       pick_result_string},
       {});
 }
 

src/core/load_balancing/subchannel_interface.h

@@ -63,8 +63,6 @@ class SubchannelInterface : public DualRefCounted<SubchannelInterface> {
 
   ~SubchannelInterface() override = default;
 
-  void Orphan() override {}
-
   // Starts watching the subchannel's connectivity state.
   // The first callback to the watcher will be delivered ~immediately.
   // Subsequent callbacks will be delivered as the subchannel's state
@@ -100,6 +98,9 @@ class SubchannelInterface : public DualRefCounted<SubchannelInterface> {
 
   // Cancels a data watch.
   virtual void CancelDataWatcher(DataWatcherInterface* watcher) = 0;
+
+ protected:
+  void Orphaned() override {}
 };
 
 // A class that delegates to another subchannel, to be used in cases

src/core/load_balancing/weighted_round_robin/weighted_round_robin.cc

@@ -67,12 +67,12 @@
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/load_balancing/backend_metric_data.h"
 #include "src/core/load_balancing/endpoint_list.h"
-#include "src/core/load_balancing/oob_backend_metric.h"
-#include "src/core/load_balancing/weighted_round_robin/static_stride_scheduler.h"
-#include "src/core/load_balancing/weighted_target/weighted_target.h"
 #include "src/core/load_balancing/lb_policy.h"
 #include "src/core/load_balancing/lb_policy_factory.h"
+#include "src/core/load_balancing/oob_backend_metric.h"
 #include "src/core/load_balancing/subchannel_interface.h"
+#include "src/core/load_balancing/weighted_round_robin/static_stride_scheduler.h"
+#include "src/core/load_balancing/weighted_target/weighted_target.h"
 #include "src/core/resolver/endpoint_addresses.h"
 
 namespace grpc_core {
@@ -85,13 +85,12 @@ constexpr absl::string_view kWeightedRoundRobin = "weighted_round_robin";
 
 constexpr absl::string_view kMetricLabelLocality = "grpc.lb.locality";
 
-const auto kMetricRrFallback =
-    GlobalInstrumentsRegistry::RegisterUInt64Counter(
-        "grpc.lb.wrr.rr_fallback",
-        "EXPERIMENTAL.  Number of scheduler updates in which there were not "
-        "enough endpoints with valid weight, which caused the WRR policy to "
-        "fall back to RR behavior.",
-        "{update}", {kMetricLabelTarget}, {kMetricLabelLocality}, false);
+const auto kMetricRrFallback = GlobalInstrumentsRegistry::RegisterUInt64Counter(
+    "grpc.lb.wrr.rr_fallback",
+    "EXPERIMENTAL.  Number of scheduler updates in which there were not "
+    "enough endpoints with valid weight, which caused the WRR policy to "
+    "fall back to RR behavior.",
+    "{update}", {kMetricLabelTarget}, {kMetricLabelLocality}, false);
 
 const auto kMetricEndpointWeightNotYetUsable =
     GlobalInstrumentsRegistry::RegisterUInt64Counter(
@@ -319,8 +318,6 @@ class WeightedRoundRobin : public LoadBalancingPolicy {
 
     PickResult Pick(PickArgs args) override;
 
-    void Orphan() override;
-
    private:
     // A call tracker that collects per-call endpoint utilization reports.
     class SubchannelCallTracker : public SubchannelCallTrackerInterface {
@@ -352,6 +349,8 @@ class WeightedRoundRobin : public LoadBalancingPolicy {
       RefCountedPtr<EndpointWeight> weight;
     };
 
+    void Orphaned() override;
+
     // Returns the index into endpoints_ to be picked.
     size_t PickIndex();
 
@@ -556,7 +555,7 @@ WeightedRoundRobin::Picker::~Picker() {
   }
 }
 
-void WeightedRoundRobin::Picker::Orphan() {
+void WeightedRoundRobin::Picker::Orphaned() {
   MutexLock lock(&timer_mu_);
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_wrr_trace)) {
     gpr_log(GPR_INFO, "[WRR %p picker %p] cancelling timer", wrr_.get(), this);
@@ -616,16 +615,16 @@ void WeightedRoundRobin::Picker::BuildSchedulerAndStartTimerLocked() {
         now, config_->weight_expiration_period(), config_->blackout_period(),
         &num_not_yet_usable, &num_stale);
     weights.push_back(weight);
-    stats_plugins.RecordHistogram(
-        kMetricEndpointWeights, weight,
-        {wrr_->channel_control_helper()->GetTarget()}, {wrr_->locality_name_});
+    stats_plugins.RecordHistogram(kMetricEndpointWeights, weight,
+                                  {wrr_->channel_control_helper()->GetTarget()},
+                                  {wrr_->locality_name_});
   }
   stats_plugins.AddCounter(
       kMetricEndpointWeightNotYetUsable, num_not_yet_usable,
       {wrr_->channel_control_helper()->GetTarget()}, {wrr_->locality_name_});
-  stats_plugins.AddCounter(
-      kMetricEndpointWeightStale, num_stale,
-      {wrr_->channel_control_helper()->GetTarget()}, {wrr_->locality_name_});
+  stats_plugins.AddCounter(kMetricEndpointWeightStale, num_stale,
+                           {wrr_->channel_control_helper()->GetTarget()},
+                           {wrr_->locality_name_});
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_wrr_trace)) {
     gpr_log(GPR_INFO, "[WRR %p picker %p] new weights: %s", wrr_.get(), this,
             absl::StrJoin(weights, " ").c_str());
@@ -645,9 +644,9 @@ void WeightedRoundRobin::Picker::BuildSchedulerAndStartTimerLocked() {
       gpr_log(GPR_INFO, "[WRR %p picker %p] no scheduler, falling back to RR",
               wrr_.get(), this);
     }
-    stats_plugins.AddCounter(
-        kMetricRrFallback, 1, {wrr_->channel_control_helper()->GetTarget()},
-        {wrr_->locality_name_});
+    stats_plugins.AddCounter(kMetricRrFallback, 1,
+                             {wrr_->channel_control_helper()->GetTarget()},
+                             {wrr_->locality_name_});
   }
   {
     MutexLock lock(&scheduler_mu_);

src/core/load_balancing/xds/xds_override_host.cc

@@ -48,7 +48,6 @@
 #include <grpc/support/log.h>
 
 #include "src/core/client_channel/client_channel_internal.h"
-#include "src/core/load_balancing/child_policy_handler.h"
 #include "src/core/ext/filters/stateful_session/stateful_session_filter.h"
 #include "src/core/ext/xds/xds_health_status.h"
 #include "src/core/lib/address_utils/parse_address.h"
@@ -75,6 +74,7 @@
 #include "src/core/lib/json/json_args.h"
 #include "src/core/lib/json/json_object_loader.h"
 #include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/load_balancing/child_policy_handler.h"
 #include "src/core/load_balancing/delegating_helper.h"
 #include "src/core/load_balancing/lb_policy.h"
 #include "src/core/load_balancing/lb_policy_factory.h"
@@ -182,8 +182,7 @@ class XdsOverrideHostLb : public LoadBalancingPolicy {
       WeakRefCountedPtr<SubchannelWrapper> subchannel_;
     };
 
-    void Orphan() override;
-
+    void Orphaned() override;
     void UpdateConnectivityState(grpc_connectivity_state state,
                                  absl::Status status);
 
@@ -1112,7 +1111,7 @@ void XdsOverrideHostLb::SubchannelWrapper::CancelConnectivityStateWatch(
   }
 }
 
-void XdsOverrideHostLb::SubchannelWrapper::Orphan() {
+void XdsOverrideHostLb::SubchannelWrapper::Orphaned() {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_override_host_trace)) {
     gpr_log(GPR_INFO,
             "[xds_override_host_lb %p] subchannel wrapper %p orphaned",

src/core/resolver/xds/xds_dependency_manager.cc

@@ -330,7 +330,7 @@ class XdsDependencyManager::DnsResultHandler : public Resolver::ResultHandler {
 // XdsDependencyManager::ClusterSubscription
 //
 
-void XdsDependencyManager::ClusterSubscription::Orphan() {
+void XdsDependencyManager::ClusterSubscription::Orphaned() {
   dependency_mgr_->work_serializer_->Run(
       [self = WeakRef()]() {
         self->dependency_mgr_->OnClusterSubscriptionUnref(self->cluster_name_,

src/core/resolver/xds/xds_dependency_manager.h

@@ -124,11 +124,11 @@ class XdsDependencyManager : public RefCounted<XdsDependencyManager>,
         : cluster_name_(cluster_name),
           dependency_mgr_(std::move(dependency_mgr)) {}
 
-    void Orphan() override;
-
     absl::string_view cluster_name() const { return cluster_name_; }
 
    private:
+    void Orphaned() override;
+
     std::string cluster_name_;
     RefCountedPtr<XdsDependencyManager> dependency_mgr_;
   };

src/core/resolver/xds/xds_resolver.cc

@@ -79,20 +79,20 @@
 #include "src/core/lib/iomgr/pollset_set.h"
 #include "src/core/lib/promise/arena_promise.h"
 #include "src/core/lib/promise/context.h"
-#include "src/core/resolver/endpoint_addresses.h"
-#include "src/core/resolver/resolver.h"
-#include "src/core/resolver/resolver_factory.h"
 #include "src/core/lib/resource_quota/arena.h"
-#include "src/core/service_config/service_config.h"
-#include "src/core/service_config/service_config_impl.h"
 #include "src/core/lib/slice/slice.h"
 #include "src/core/lib/transport/metadata_batch.h"
 #include "src/core/lib/transport/transport.h"
 #include "src/core/lib/uri/uri_parser.h"
 #include "src/core/load_balancing/ring_hash/ring_hash.h"
+#include "src/core/resolver/endpoint_addresses.h"
+#include "src/core/resolver/resolver.h"
+#include "src/core/resolver/resolver_factory.h"
 #include "src/core/resolver/xds/xds_dependency_manager.h"
 #include "src/core/resolver/xds/xds_resolver_attributes.h"
 #include "src/core/resolver/xds/xds_resolver_trace.h"
+#include "src/core/service_config/service_config.h"
+#include "src/core/service_config/service_config_impl.h"
 
 namespace grpc_core {
 
@@ -173,7 +173,7 @@ class XdsResolver : public Resolver {
           cluster_subscription_(std::move(cluster_subscription)),
           cluster_key_(cluster_key) {}
 
-    void Orphan() override {
+    void Orphaned() override {
       XdsResolver* resolver_ptr = resolver_.get();
       resolver_ptr->work_serializer_->Run(
           [resolver = std::move(resolver_)]() {

test/core/client_channel/lb_policy/lb_policy_test_lib.h

@@ -510,7 +510,7 @@ class LoadBalancingPolicyTest : public ::testing::Test {
                 picker_.get());
       }
 
-      void Orphan() override {
+      void Orphaned() override {
         absl::Notification notification;
         ExecCtx exec_ctx;
         test_->work_serializer_->Run(

test/core/event_engine/posix/event_poller_posix_test.cc

@@ -585,7 +585,7 @@ class WakeupFdHandle : public grpc_core::DualRefCounted<WakeupFdHandle> {
 
   ~WakeupFdHandle() override { delete on_read_; }
 
-  void Orphan() override {
+  void Orphaned() override {
     // Once the handle has orphaned itself, decrement
     // kTotalActiveWakeupFdHandles. Once all handles have orphaned themselves,
     // send a Kick to the poller.
@@ -650,7 +650,7 @@ class Worker : public grpc_core::DualRefCounted<Worker> {
     }
     WeakRef().release();
   }
-  void Orphan() override { signal.Notify(); }
+  void Orphaned() override { signal.Notify(); }
   void Start() {
     // Start executing Work(..).
     scheduler_->Run([this]() { Work(); });

test/core/event_engine/posix/posix_endpoint_test.cc

@@ -156,7 +156,7 @@ class Worker : public grpc_core::DualRefCounted<Worker> {
       : engine_(std::move(engine)), poller_(poller) {
     WeakRef().release();
   }
-  void Orphan() override { signal.Notify(); }
+  void Orphaned() override { signal.Notify(); }
   void Start() {
     // Start executing Work(..).
     engine_->Run([this]() { Work(); });

test/core/gprpp/dual_ref_counted_test.cc

@@ -31,7 +31,7 @@ class Foo : public DualRefCounted<Foo> {
   Foo() = default;
   ~Foo() override { GPR_ASSERT(shutting_down_); }
 
-  void Orphan() override { shutting_down_ = true; }
+  void Orphaned() override { shutting_down_ = true; }
 
  private:
   bool shutting_down_ = false;
@@ -94,7 +94,7 @@ class FooWithTracing : public DualRefCounted<FooWithTracing> {
   FooWithTracing() : DualRefCounted("FooWithTracing") {}
   ~FooWithTracing() override { GPR_ASSERT(shutting_down_); }
 
-  void Orphan() override { shutting_down_ = true; }
+  void Orphaned() override { shutting_down_ = true; }
 
  private:
   bool shutting_down_ = false;

test/core/gprpp/ref_counted_ptr_test.cc

@@ -276,7 +276,7 @@ class Bar : public DualRefCounted<Bar> {
 
   ~Bar() override { GPR_ASSERT(shutting_down_); }
 
-  void Orphan() override { shutting_down_ = true; }
+  void Orphaned() override { shutting_down_ = true; }
 
   int value() const { return value_; }
 
@@ -432,7 +432,7 @@ class BarWithTracing : public DualRefCounted<BarWithTracing> {
 
   ~BarWithTracing() override { GPR_ASSERT(shutting_down_); }
 
-  void Orphan() override { shutting_down_ = true; }
+  void Orphaned() override { shutting_down_ = true; }
 
  private:
   bool shutting_down_ = false;
@@ -455,7 +455,7 @@ class WeakBaseClass : public DualRefCounted<WeakBaseClass> {
 
   ~WeakBaseClass() override { GPR_ASSERT(shutting_down_); }
 
-  void Orphan() override { shutting_down_ = true; }
+  void Orphaned() override { shutting_down_ = true; }
 
  private:
   bool shutting_down_ = false;

test/core/server_config_selector/server_config_selector_test.cc

@@ -36,7 +36,7 @@ class TestServerConfigSelectorProvider : public ServerConfigSelectorProvider {
     return absl::UnavailableError("Test ServerConfigSelector");
   }
 
-  void Orphan() override {}
+  void Orphaned() override {}
 
   void CancelWatch() override {}
 };