Null Reference, dialogue object won't create a default node?

[plant]

I made sure to copy the code exactly as per the video, but I keep getting null reference errors coming from the dialogue script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace RPG.Dialogue
{
    [CreateAssetMenu(fileName = "New Dialogue", menuName = "Dialogue", order = 0)]
    public class Dialogue : ScriptableObject
    {
        [SerializeField]
        List<DialogueNode> nodes;

#if UNITY_EDITOR
        private void Awake()
        {
            if (nodes.Count == 0) //error is referencing this line
            {
                nodes.Add(new DialogueNode());
            }
        }
#endif
        public IEnumerable<DialogueNode> GetAllNodes()
        {
            return nodes;
        }
    }
}

I can’t quite pinpoint the reason why it won’t create a default node?

[plant]

Just to confirm, I am using version 2020.1.3f1 as advised in the project set up video, however this doesn’t appear to be a versioning issue.

As an aside, upgrading the RPG project to 2020 broke all of the animations and combat logic, is this version absolutely mandatory for this course?

Update: The animation issue is resolved. Must have just been a glitch, because opening the Animator window and closing it again cleared it right up. Still not sure whats wrong with my dialogue nodes though!

[111100]

size of array is zero. Thats reason. Type any other number.

[Brian_Trotter]

@plant

        [SerializeField]
        List<DialogueNode> nodes;

This line is your culprit. The list doesn’t technically exist in Awake() the first time you create a Dialogue because it’s not initialized in the field declaration.
Try this:

[SerializeField] List<DialogueNode> nodes = new List<DialogueNode>();

[plant]

Thank you Brian, that fixed the issue!