C++ FlatBuffers - Assertion failed: (finished), function Finished - c++

Question

Here is my schema:
namespace Vibranium;
enum GameObject_Type:uint { STATIC = 0 }
table GameObjectDatabase
{
gameobjects:[GameObjectsTemplate];
}
table GameObjectsTemplate
{
id:int;
name:string;
prefab:string;
type:GameObject_Type;
position_x:float;
position_y:float;
position_z:float;
rotation_x:float;
rotation_y:float;
rotation_z:float;
map_id:int;
event_id:int;
}
root_type GameObjectDatabase;
Here is my code:
flatbuffers::FlatBufferBuilder fbb;
std::vector<flatbuffers::Offset<Vibranium::GameObjectsTemplate>> gameobjects_template;
Field* fields = result->Fetch();
auto id = fields[0].GetInt32();
auto name = fbb.CreateString(fields[1].GetString());
auto prefab = fbb.CreateString(fields[2].GetString());
auto type = static_cast<Vibranium::GameObject_Type>(fields[3].GetInt32());
auto position_x = fields[5].GetFloat();
auto position_y = fields[6].GetFloat();
auto position_z = fields[7].GetFloat();
auto rotation_x = fields[8].GetFloat();
auto rotation_y = fields[9].GetFloat();
auto rotation_z = fields[10].GetFloat();
auto map_id = fields[11].GetInt32();
auto event_id = fields[12].GetInt32();
auto go1 = Vibranium::CreateGameObjectsTemplate(fbb, id, name, prefab, type,position_x,position_y,position_z, rotation_x,rotation_y,rotation_z,map_id,event_id);
gameobjects_template.push_back(go1);
this->_container.push_back(go1);
auto go_db = fbb.CreateVector(gameobjects_template);
Vibranium::GameObjectDatabaseBuilder go_builder(fbb);
go_builder.add_gameobjects(go_db);
go_builder.Finish();
auto gt = Vibranium::GetGameObjectDatabase(fbb.GetBufferPointer());
I get this error:
Assertion failed: (finished), function Finished, file /opt/homebrew/include/flatbuffers/flatbuffers.h, line 1226.
It is caused by this line:
auto gt = Vibranium::GetGameObjectDatabase(fbb.GetBufferPointer());
Why is that and how can I fix it?

Answer 1

If you get an assert, it is always good to check the assert code, it may give you a hint as to why:
void Finished() const {
// If you get this assert, you're attempting to get access a buffer
// which hasn't been finished yet. Be sure to call
// FlatBufferBuilder::Finish with your root table.
// If you really need to access an unfinished buffer, call
// GetCurrentBufferPointer instead.
FLATBUFFERS_ASSERT(finished);
}