Fix asset scan startup crash (#4554)

* Fix calling managed AssetScanComplete to early

Editor::AssetSystem::AssetScanComplete(); was called at the end of PruneStaleAssets() in the UpdateMods() path. Before BuildDependencyData() ran, which is unsafe since AssetScanComplete() needs full dependency infomration

* Restore some menu transients that shouldnt have been pruned

* Don't orphan assets if they have a parent

* Dont Oprhan menu transients, they may be referenced by otehr projects (yikes)

Author: lolleko

engine/Sandbox.Tools/Assets/Asset.cs

@@ -203,6 +203,12 @@ public void RebuildThumbnail( bool startBuild = true )
 	/// <param name="deep">Whether to recurse. For example, will also include maps that are using models which use this material asset, as opposed to returning just the models.</param>
 	public abstract List<Asset> GetDependants( bool deep );
 
+	/// <summary>
+	/// Returns assets that are parents of this asset (i.e. this asset is a compiled child resource of the returned assets).
+	/// </summary>
+	/// <param name="deep">Whether to recurse up the parent chain.</param>
+	public abstract List<Asset> GetParents( bool deep );
+
 	List<Asset> GetAssetList( NativeEngine.CUtlVectorAsset v, bool free )
 	{
 		var l = new List<Asset>();

engine/Sandbox.Tools/Assets/AssetSystem.cs

@@ -274,11 +274,17 @@ public static Asset RegisterFile( string absoluteFilePath )
 	/// </summary>
 	public static void DeleteOrphans()
 	{
+		// Only delete orphans from the current project's transient folder.
+		// Engine-shipped transients (e.g. addons/menu/Transients/) are shared
+		// across all projects and must not be deleted.
+		var transientRoot = FileSystem.Transient?.GetFullPath( "/" )?.NormalizeFilename( false );
+
 		var orphans = All
 						.Where( x => x.IsTrivialChild )
 						.Where( x => !x.IsDeleted )
 						.Where( x => x.AssetType == AssetType.Texture ) // Note - gib models can be trivial children too, but I don't want to push my luck
-						.Where( x => x.GetDependants( false ).Count == 0 )
+						.Where( x => transientRoot is not null && x.AbsolutePath.StartsWith( transientRoot, StringComparison.OrdinalIgnoreCase ) )
+						.Where( x => x.GetDependants( false ).Count == 0 && x.GetParents( false ).Count == 0 )
 						.ToArray();
 
 		foreach ( var o in orphans )

engine/Sandbox.Tools/Assets/EmbeddedAsset/EmbeddedAsset.cs

@@ -65,6 +65,11 @@ public override List<Asset> GetDependants( bool deep )
 		return [];
 	}
 
+	public override List<Asset> GetParents( bool deep )
+	{
+		return [];
+	}
+
 	public override List<string> GetAdditionalContentFiles()
 	{
 		return [];

engine/Sandbox.Tools/Assets/MountAsset/MountAsset.cs

@@ -47,6 +47,7 @@ public override void OpenInEditor( string nativeEditor = null ) { } // I don't t
 
 	public override List<Asset> GetReferences( bool deep ) => new List<Asset>();
 	public override List<Asset> GetDependants( bool deep ) => new List<Asset>();
+	public override List<Asset> GetParents( bool deep ) => new List<Asset>();
 	public override List<string> GetAdditionalContentFiles() => new List<string>();
 	public override List<string> GetAdditionalGameFiles() => new List<string>();
 	public override List<string> GetInputDependencies() => new List<string>();

engine/Sandbox.Tools/Assets/NativeAsset/NativeAsset.cs

@@ -150,6 +150,16 @@ public override List<Asset> GetDependants( bool deep )
 		return GetAssetList( list, true );
 	}
 
+	/// <summary>
+	/// Returns assets that are parents of this asset.
+	/// </summary>
+	public override List<Asset> GetParents( bool deep )
+	{
+		var list = NativeEngine.CUtlVectorAsset.Create( 4, 4 );
+		native.GetAssetsParentingMe( list, deep );
+		return GetAssetList( list, true );
+	}
+
 	List<Asset> GetAssetList( NativeEngine.CUtlVectorAsset v, bool free )
 	{
 		var l = new List<Asset>();