propagate error code in case of client reset errors in the callback

src/realm/object-store/c_api/config.cpp

@@ -143,10 +143,11 @@ RLM_API void realm_config_set_should_compact_on_launch_function(realm_config_t*
 {
     if (func) {
         auto should_func = [=](uint64_t total_bytes, uint64_t used_bytes) -> bool {
-            auto result = func(userdata, total_bytes, used_bytes);
-            if (auto usercode_error = ErrorStorage::get_thread_local()->get_and_clear_usercode_error())
-                throw CallbackFailed{usercode_error};
-            return result;
+            if (!func(userdata, total_bytes, used_bytes)) {
+                throw CallbackFailed{ErrorStorage::get_thread_local()->get_and_clear_usercode_error()};
+                return false;
+            }
+            return true;
         };
         config->should_compact_on_launch_function = std::move(should_func);
     }

src/realm/object-store/c_api/sync.cpp

@@ -388,7 +388,7 @@ RLM_API void realm_sync_config_set_before_client_reset_handler(realm_sync_config
     auto cb = [callback, userdata = SharedUserdata(userdata, FreeUserdata(userdata_free))](SharedRealm before_realm) {
         realm_t r1{before_realm};
         if (!callback(userdata.get(), &r1)) {
-            throw CallbackFailed();
+            throw CallbackFailed{ErrorStorage::get_thread_local()->get_and_clear_usercode_error()};
         }
     };
     config->notify_before_client_reset = std::move(cb);
@@ -404,7 +404,7 @@ RLM_API void realm_sync_config_set_after_client_reset_handler(realm_sync_config_
         realm_t r1{before_realm};
         auto tsr = realm_t::thread_safe_reference(std::move(after_realm));
         if (!callback(userdata.get(), &r1, &tsr, did_recover)) {
-            throw CallbackFailed();
+            throw CallbackFailed{ErrorStorage::get_thread_local()->get_and_clear_usercode_error()};
         }
     };
     config->notify_after_client_reset = std::move(cb);