BitmapValue::write_to will get a string with size 1 for empty BitmapValue, however the size 1 string will reinterpret to BitmapValue* back in ColumnComplexType::insert:
void insert(const Field& x) override {
const String& s = doris::vectorized::get<const String&>(x);
data.push_back(reinterpret_cast<const T>(s.c_str()));
}
in data.push_back will goto BitmapValue copy constructor, as the _type is not first member in BitmapValue, cause access to an unknown memory location.