Script to auto-generate assemblies for back-compatibility with Unity3D's "Editor" folder magic

AssemblyDefinitionSwitch.cs

// Adapted from
// https://www.3delement.com/?p=586

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

class AssemblyDefinitionType // type used to load the .asmdef as json
{
    public string name;
    public List<string> references = new List<string>();
    public List<string> includePlatforms = new List<string>();
    public List<string> excludePlatforms = new List<string>();
    public bool allowUnsafeCode = true;
    public bool overrideReferences = false;
    public List<string> precompiledReferences = new List<string>();
    public bool autoReferenced = true;
    public List<string> defineConstraints = new List<string>();
    public List<string> versionDefines = new List<string>();
}


public class AssemblyDefinitionSwitch
{
    [MenuItem("Tools/Create EditorAssemblyDefFiles")]
    public static void TurnOnAssembly()
    {
        CreateEditorFiles(new DirectoryInfo(Application.dataPath), null, false);
        AssetDatabase.Refresh();
    }

    [MenuItem("Tools/Delete EditorAssemblyDefFiles")]
    public static void TurnOffAssembly()
    {
        CreateEditorFiles(new DirectoryInfo(Application.dataPath), null, true);
        AssetDatabase.Refresh();
    }

    static List<string> EditorAssemblySibilings;
    static int duplicateNum = 0;

    static string AssetGuid(string path) {
        var assetRoot = Application.dataPath.Remove(Application.dataPath.Length - "Assets".Length);
        var assetPath = path.Remove(0, assetRoot.Length);
        Debug.Log($"path={path} assetRoot={assetRoot} assetPath={assetPath}");
        var asset = AssetDatabase.LoadAssetAtPath<UnityEngine.Object>(assetPath);
        if (AssetDatabase.TryGetGUIDAndLocalFileIdentifier(asset, out var guid, out long _)) {
            return guid;
        }
        throw new System.InvalidOperationException($"Could not find asset at {path}");
    }

    static void CreateEditorFiles(DirectoryInfo Dir, FileInfo parentAsmdef, bool Remove)
    {
        // var cybermonkAsmdef = AssetDatabase.LoadAssetAtPath<UnityEngine.Object>("Cybermonk/Cybermonk.asmdef");
        // var everythingAsmdef = AssetDatabase.LoadAssetAtPath<UnityEngine.Object>("Everything.asmdef");

        FileInfo[] files = Dir.GetFiles();
        foreach (FileInfo file in files)
        {
            if (file.Extension == ".asmdef")
            {
                parentAsmdef = file;
                EditorAssemblySibilings = new List<string>();
                duplicateNum = 1;
            }
        }

        if (parentAsmdef != null)
        {
            DirectoryInfo[] dirs = Dir.GetDirectories();
            foreach (DirectoryInfo subdir in dirs)
            {
                if (subdir.Name == "Editor")
                {
                    FileInfo[] editorfiles = subdir.GetFiles();
                    foreach (FileInfo file in editorfiles)
                    {
                        // Delete old asmdef editor folder files
                        if (file.Extension == ".asmdef")
                        {
                            File.Delete(file.FullName);
                        }
                    }
                    if (!Remove)
                    {
                        // create a assemb file based on the Parent one, only with includePlatforms changed to Editor
                        // assembly name is the parent assembly name + directory that contains the editor folder + "Editor"

                        AssemblyDefinitionType EditorAssemb = JsonUtility.FromJson<AssemblyDefinitionType>(File.ReadAllText(parentAsmdef.FullName));
                        EditorAssemb.references.Add($"GUID:{AssetGuid(parentAsmdef.FullName)}"); // add parent assembly as a reference
                        // EditorAssemb.references.Add(EditorAssemb.name); // add parent assembly as a reference
                        EditorAssemb.references.AddRange(EditorAssemblySibilings); // for subeditor folders to reference the above editor assemblies

                        EditorAssemb.name = "z_" + EditorAssemb.name + Dir.Name + "Editor"; // added z_ to be at bottom of solution explorer
                        if (EditorAssemblySibilings.Contains(EditorAssemb.name))
                        {
                            EditorAssemb.name += duplicateNum;
                            duplicateNum += 1;
                        }
                        EditorAssemblySibilings.Add(EditorAssemb.name);
                        EditorAssemb.includePlatforms = new List<string>();
                        EditorAssemb.includePlatforms.Add("Editor");
                        File.WriteAllText(Path.Combine(subdir.FullName, EditorAssemb.name + ".asmdef"), JsonUtility.ToJson(EditorAssemb));
                    }
                }
            }
        }

        DirectoryInfo[] dirs2 = Dir.GetDirectories();
        foreach (DirectoryInfo subdir in dirs2)
        {
            if (subdir.Name != "Editor")
                CreateEditorFiles(subdir, parentAsmdef, Remove);
        }
    }
}