new-git/Assets/GitMerge/Editor/ConflictWatcher.cs

using System;
using System.Collections.Generic;
using System.IO;
using UnityEditor;
using UnityEngine;

namespace GitMerge
{
    [InitializeOnLoad]
    public class ConflictWatcher
{
    private static FileSystemWatcher watcher;
    private static FileSystemEventArgs e;
    
    public ConflictWatcher()
    {
        string assetPath = Application.dataPath;
        watcher = new FileSystemWatcher(assetPath);
        watcher.IncludeSubdirectories = true;
        watcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName;
        watcher.Changed += OnFileChanged;
        watcher.EnableRaisingEvents = true;
    }

    public event Action<string> OnConflict;

    private void OnFileChanged(object sender, FileSystemEventArgs _e)
    {
        e = _e;
        EditorApplication.update += CheckWindow;
    }

    private void CheckWindow()
    {
        AssetDatabase.Refresh();
        EditorApplication.update -= CheckWindow;
        var path = e.FullPath;
        var relativePath = "Assets" + path.Substring(Application.dataPath.Length);
        
        Debug.Log(relativePath);
        if (!path.EndsWith(".unity") && !path.EndsWith(".prefab")) return;
        // Found it
        UnityEngine.Object asset;
        try
        {
            asset = AssetDatabase.LoadAssetAtPath<UnityEngine.Object>(relativePath);
        }
        catch (Exception exception)
        {
            Debug.Log(exception);
            throw;
        }
        Debug.Log("asset" + asset);
        if (asset != null)
        {
            Debug.Log("Found asset" + asset.GetType());
            bool isBroken = asset is BrokenPrefabAsset;
                
            // Open merge conflict window
            if (isBroken)
            {
                OnConflict?.Invoke(relativePath);
            }
        }
    }
    
    static bool IsOpenForEdit(string[] paths, List<string> outNotEditablePaths, StatusQueryOptions statusQueryOptions)
    {
        Debug.Log("IsOpenForEdit:");
        // TODO: Do locking/unlocking here

        foreach (var path in paths)
        {
            // Check for lock
            Debug.Log(path);
        }
        return true;
    }
}    
}