Merge pull request #20329 from soheilhy/call-op-str

Avoid creating and copying strings when Status is OK in FinishOp.

include/grpcpp/impl/codegen/call_op_set.h

@@ -772,19 +772,23 @@ class CallOpClientRecvStatus {
 
   void FinishOp(bool* /*status*/) {
     if (recv_status_ == nullptr || hijacked_) return;
-    grpc::string binary_error_details = metadata_map_->GetBinaryErrorDetails();
-    *recv_status_ =
-        Status(static_cast<StatusCode>(status_code_),
-               GRPC_SLICE_IS_EMPTY(error_message_)
-                   ? grpc::string()
-                   : grpc::string(GRPC_SLICE_START_PTR(error_message_),
-                                  GRPC_SLICE_END_PTR(error_message_)),
-               binary_error_details);
-    client_context_->set_debug_error_string(
-        debug_error_string_ != nullptr ? debug_error_string_ : "");
-    g_core_codegen_interface->grpc_slice_unref(error_message_);
-    if (debug_error_string_ != nullptr) {
-      g_core_codegen_interface->gpr_free((void*)debug_error_string_);
+    if (status_code_ == StatusCode::OK) {
+      *recv_status_ = Status();
+      GPR_CODEGEN_DEBUG_ASSERT(GRPC_SLICE_IS_EMPTY(error_message_));
+      GPR_CODEGEN_DEBUG_ASSERT(debug_error_string_ == nullptr);
+    } else {
+      *recv_status_ =
+          Status(static_cast<StatusCode>(status_code_),
+                 GRPC_SLICE_IS_EMPTY(error_message_)
+                     ? grpc::string()
+                     : grpc::string(GRPC_SLICE_START_PTR(error_message_),
+                                    GRPC_SLICE_END_PTR(error_message_)),
+                 metadata_map_->GetBinaryErrorDetails());
+      g_core_codegen_interface->grpc_slice_unref(error_message_);
+      if (debug_error_string_ != nullptr) {
+        client_context_->set_debug_error_string(debug_error_string_);
+        g_core_codegen_interface->gpr_free((void*)debug_error_string_);
+      }
     }
   }