Revert the revert to server.cc

1 files changed, 34 insertions, 8 deletions

diff --git a/src/core/lib/surface/server.cc b/src/core/lib/surface/server.cc
index 5fa58ffdec..72ddc2648d 100644
--- a/src/core/lib/surface/server.cc
+++ b/src/core/lib/surface/server.cc
@@ -150,12 +150,15 @@ struct call_data {
   grpc_closure kill_zombie_closure;
   grpc_closure* on_done_recv_initial_metadata;
   grpc_closure recv_trailing_metadata_ready;
-  grpc_error* error;
+  grpc_error* recv_initial_metadata_error;
   grpc_closure* original_recv_trailing_metadata_ready;
+  grpc_error* recv_trailing_metadata_error;
+  bool seen_recv_trailing_metadata_ready;
 
   grpc_closure publish;
 
   call_data* pending_next;
+  grpc_call_combiner* call_combiner;
 };
 
 struct request_matcher {
@@ -727,21 +730,43 @@ static void server_on_recv_initial_metadata(void* ptr, grpc_error* error) {
   if (calld->host_set && calld->path_set) {
     /* do nothing */
   } else {
+    /* Pass the error reference to calld->recv_initial_metadata_error */
     grpc_error* src_error = error;
     error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-        "Missing :authority or :path", &error, 1);
+        "Missing :authority or :path", &src_error, 1);
     GRPC_ERROR_UNREF(src_error);
+    calld->recv_initial_metadata_error = GRPC_ERROR_REF(error);
   }
-
-  GRPC_CLOSURE_RUN(calld->on_done_recv_initial_metadata, error);
+  grpc_closure* closure = calld->on_done_recv_initial_metadata;
+  calld->on_done_recv_initial_metadata = nullptr;
+  if (calld->seen_recv_trailing_metadata_ready) {
+    GRPC_CALL_COMBINER_START(calld->call_combiner,
+                             &calld->recv_trailing_metadata_ready,
+                             calld->recv_trailing_metadata_error,
+                             "continue server_recv_trailing_metadata_ready");
+  }
+  GRPC_CLOSURE_RUN(closure, error);
 }
 
 static void server_recv_trailing_metadata_ready(void* user_data,
-                                                grpc_error* err) {
+                                                grpc_error* error) {
   grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
   call_data* calld = static_cast<call_data*>(elem->call_data);
-  err = grpc_error_add_child(GRPC_ERROR_REF(err), GRPC_ERROR_REF(calld->error));
-  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, err);
+  if (calld->on_done_recv_initial_metadata != nullptr) {
+    calld->recv_trailing_metadata_error = GRPC_ERROR_REF(error);
+    calld->seen_recv_trailing_metadata_ready = true;
+    GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready,
+                      server_recv_trailing_metadata_ready, elem,
+                      grpc_schedule_on_exec_ctx);
+    GRPC_CALL_COMBINER_STOP(calld->call_combiner,
+                            "deferring server_recv_trailing_metadata_ready "
+                            "until after server_on_recv_initial_metadata");
+    return;
+  }
+  error =
+      grpc_error_add_child(GRPC_ERROR_REF(error),
+                           GRPC_ERROR_REF(calld->recv_initial_metadata_error));
+  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, error);
 }
 
 static void server_mutate_op(grpc_call_element* elem,
@@ -845,6 +870,7 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
   memset(calld, 0, sizeof(call_data));
   calld->deadline = GRPC_MILLIS_INF_FUTURE;
   calld->call = grpc_call_from_top_element(elem);
+  calld->call_combiner = args->call_combiner;
 
   GRPC_CLOSURE_INIT(&calld->server_on_recv_initial_metadata,
                     server_on_recv_initial_metadata, elem,
@@ -863,7 +889,7 @@ static void destroy_call_elem(grpc_call_element* elem,
   call_data* calld = static_cast<call_data*>(elem->call_data);
 
   GPR_ASSERT(calld->state != PENDING);
-  GRPC_ERROR_UNREF(calld->error);
+  GRPC_ERROR_UNREF(calld->recv_initial_metadata_error);
   if (calld->host_set) {
     grpc_slice_unref_internal(calld->host);
   }