1 files changed, 12 insertions, 3 deletions
diff --git a/src/csharp/Grpc.IntegrationTesting/Payloads.cs b/src/csharp/Grpc.IntegrationTesting/Payloads.cs
index f918b9576b..fca8cda6f6 100644
--- a/src/csharp/Grpc.IntegrationTesting/Payloads.cs
+++ b/src/csharp/Grpc.IntegrationTesting/Payloads.cs
@@ -596,13 +596,22 @@ namespace Grpc.Testing {
       }
       switch (other.PayloadCase) {
         case PayloadOneofCase.BytebufParams:
-          BytebufParams = other.BytebufParams;
+          if (BytebufParams == null) {
+            BytebufParams = new global::Grpc.Testing.ByteBufferParams();
+          }
+          BytebufParams.MergeFrom(other.BytebufParams);
           break;
         case PayloadOneofCase.SimpleParams:
-          SimpleParams = other.SimpleParams;
+          if (SimpleParams == null) {
+            SimpleParams = new global::Grpc.Testing.SimpleProtoParams();
+          }
+          SimpleParams.MergeFrom(other.SimpleParams);
           break;
         case PayloadOneofCase.ComplexParams:
-          ComplexParams = other.ComplexParams;
+          if (ComplexParams == null) {
+            ComplexParams = new global::Grpc.Testing.ComplexProtoParams();
+          }
+          ComplexParams.MergeFrom(other.ComplexParams);
           break;
       }