Update get_parent_id to clarify its unsafe and suppress warning.

src/log_surgeon/finite_automata/PrefixTree.cpp

@@ -13,7 +13,7 @@ auto PrefixTree::get_reversed_positions(id_t const node_id) const -> std::vector
     auto current_node{m_nodes[node_id]};
     while (false == current_node.is_root()) {
         reversed_positions.push_back(current_node.get_position());
-        current_node = m_nodes[current_node.get_parent_node_id().value()];
+        current_node = m_nodes[current_node.get_parent_id_unsafe()];
     }
     return reversed_positions;
 }

src/log_surgeon/finite_automata/PrefixTree.hpp

@@ -59,22 +59,23 @@ class PrefixTree {
 private:
     class Node {
     public:
-        Node(std::optional<id_t> const parent_node_id, position_t const position)
-                : m_parent_node_id{parent_node_id},
+        Node(std::optional<id_t> const parent_id, position_t const position)
+                : m_parent_id{parent_id},
                   m_position{position} {}
 
-        [[nodiscard]] auto is_root() const -> bool { return false == m_parent_node_id.has_value(); }
+        [[nodiscard]] auto is_root() const -> bool { return false == m_parent_id.has_value(); }
 
-        [[nodiscard]] auto get_parent_node_id() const -> std::optional<id_t> {
-            return m_parent_node_id;
+        [[nodiscard]] auto get_parent_id_unsafe() const -> id_t {
+            // NOLINTNEXTLINE(bugprone-unchecked-optional-access)
+            return m_parent_id.value();
         }
 
         auto set_position(position_t const position) -> void { m_position = position; }
 
         [[nodiscard]] auto get_position() const -> position_t { return m_position; }
 
     private:
-        std::optional<id_t> m_parent_node_id;
+        std::optional<id_t> m_parent_id;
         position_t m_position;
     };