1 files changed, 23 insertions, 9 deletions

diff --git a/include/grpcpp/impl/codegen/client_callback.h b/include/grpcpp/impl/codegen/client_callback.h
index 4d9579fd6a..66cf9b7754 100644
--- a/include/grpcpp/impl/codegen/client_callback.h
+++ b/include/grpcpp/impl/codegen/client_callback.h
@@ -255,10 +255,12 @@ class ClientCallbackReaderWriterImpl
 
   void MaybeFinish() {
     if (--callbacks_outstanding_ == 0) {
-      reactor_->OnDone(finish_status_);
+      Status s = std::move(finish_status_);
+      auto* reactor = reactor_;
       auto* call = call_.call();
       this->~ClientCallbackReaderWriterImpl();
       g_core_codegen_interface->grpc_call_unref(call);
+      reactor->OnDone(s);
     }
   }
 
@@ -268,6 +270,7 @@ class ClientCallbackReaderWriterImpl
     // 2. Any read backlog
     // 3. Recv trailing metadata, on_completion callback
     // 4. Any write backlog
+    // 5. See if the call can finish (if other callbacks were triggered already)
     started_ = true;
 
     start_tag_.Set(call_.call(),
@@ -318,6 +321,7 @@ class ClientCallbackReaderWriterImpl
     if (writes_done_ops_at_start_) {
       call_.PerformOps(&writes_done_ops_);
     }
+    MaybeFinish();
   }
 
   void Read(Response* msg) override {
@@ -410,8 +414,8 @@ class ClientCallbackReaderWriterImpl
   CallbackWithSuccessTag read_tag_;
   bool read_ops_at_start_{false};
 
-  // Minimum of 2 outstanding callbacks to pre-register for start and finish
-  std::atomic_int callbacks_outstanding_{2};
+  // Minimum of 3 callbacks to pre-register for StartCall, start, and finish
+  std::atomic_int callbacks_outstanding_{3};
   bool started_{false};
 };
 
@@ -450,10 +454,12 @@ class ClientCallbackReaderImpl
 
   void MaybeFinish() {
     if (--callbacks_outstanding_ == 0) {
-      reactor_->OnDone(finish_status_);
+      Status s = std::move(finish_status_);
+      auto* reactor = reactor_;
       auto* call = call_.call();
       this->~ClientCallbackReaderImpl();
       g_core_codegen_interface->grpc_call_unref(call);
+      reactor->OnDone(s);
     }
   }
 
@@ -462,6 +468,7 @@ class ClientCallbackReaderImpl
     // 1. Send initial metadata (unless corked) + recv initial metadata
     // 2. Any backlog
     // 3. Recv trailing metadata, on_completion callback
+    // 4. See if the call can finish (if other callbacks were triggered already)
     started_ = true;
 
     start_tag_.Set(call_.call(),
@@ -493,6 +500,8 @@ class ClientCallbackReaderImpl
     finish_ops_.ClientRecvStatus(context_, &finish_status_);
     finish_ops_.set_core_cq_tag(&finish_tag_);
     call_.PerformOps(&finish_ops_);
+
+    MaybeFinish();
   }
 
   void Read(Response* msg) override {
@@ -536,8 +545,8 @@ class ClientCallbackReaderImpl
   CallbackWithSuccessTag read_tag_;
   bool read_ops_at_start_{false};
 
-  // Minimum of 2 outstanding callbacks to pre-register for start and finish
-  std::atomic_int callbacks_outstanding_{2};
+  // Minimum of 3 callbacks to pre-register for StartCall, start, and finish
+  std::atomic_int callbacks_outstanding_{3};
   bool started_{false};
 };
 
@@ -576,10 +585,12 @@ class ClientCallbackWriterImpl
 
   void MaybeFinish() {
     if (--callbacks_outstanding_ == 0) {
-      reactor_->OnDone(finish_status_);
+      Status s = std::move(finish_status_);
+      auto* reactor = reactor_;
       auto* call = call_.call();
       this->~ClientCallbackWriterImpl();
       g_core_codegen_interface->grpc_call_unref(call);
+      reactor->OnDone(s);
     }
   }
 
@@ -588,6 +599,7 @@ class ClientCallbackWriterImpl
     // 1. Send initial metadata (unless corked) + recv initial metadata
     // 2. Recv trailing metadata, on_completion callback
     // 3. Any backlog
+    // 4. See if the call can finish (if other callbacks were triggered already)
     started_ = true;
 
     start_tag_.Set(call_.call(),
@@ -627,6 +639,8 @@ class ClientCallbackWriterImpl
     if (writes_done_ops_at_start_) {
       call_.PerformOps(&writes_done_ops_);
     }
+
+    MaybeFinish();
   }
 
   void Write(const Request* msg, WriteOptions options) override {
@@ -708,8 +722,8 @@ class ClientCallbackWriterImpl
   CallbackWithSuccessTag writes_done_tag_;
   bool writes_done_ops_at_start_{false};
 
-  // Minimum of 2 outstanding callbacks to pre-register for start and finish
-  std::atomic_int callbacks_outstanding_{2};
+  // Minimum of 3 callbacks to pre-register for StartCall, start, and finish
+  std::atomic_int callbacks_outstanding_{3};
   bool started_{false};
 };