xNode/Scripts/Editor/GraphRenameFixAssetProcessor.cs

using UnityEditor;
using XNode;

namespace XNodeEditor
{
    /// <summary>
    ///     This asset processor resolves an issue with the new v2 AssetDatabase system present on 2019.3 and later. When
    ///     renaming a <see cref="NodeGraph" /> asset, it appears that sometimes the v2 AssetDatabase will swap which asset
    ///     is the main asset (present at top level) between the <see cref="NodeGraph" /> and one of its <see cref="Node" />
    ///     sub-assets. As a workaround until Unity fixes this, this asset processor checks all renamed assets and if it
    ///     finds a case where a <see cref="Node" /> has been made the main asset it will swap it back to being a sub-asset
    ///     and rename the node to the default name for that node type.
    /// </summary>
    internal sealed class GraphRenameFixAssetProcessor : AssetPostprocessor
    {
        private static void OnPostprocessAllAssets(
            string[] importedAssets,
            string[] deletedAssets,
            string[] movedAssets,
            string[] movedFromAssetPaths)
        {
            for (int i = 0; i < movedAssets.Length; i++)
            {
                Node nodeAsset = AssetDatabase.LoadMainAssetAtPath(movedAssets[i]) as Node;

                // If the renamed asset is a node graph, but the v2 AssetDatabase has swapped a sub-asset node to be its
                // main asset, reset the node graph to be the main asset and rename the node asset back to its default
                // name.
                if (nodeAsset != null && AssetDatabase.IsMainAsset(nodeAsset))
                {
                    AssetDatabase.SetMainObject(nodeAsset.graph, movedAssets[i]);
                    AssetDatabase.ImportAsset(movedAssets[i]);

                    nodeAsset.name = NodeEditorUtilities.NodeDefaultName(nodeAsset.GetType());
                    EditorUtility.SetDirty(nodeAsset);
                }
            }
        }
    }
}