[WIP] Welcome Dialog

Author: raulsntos

src/Godot.EditorIntegration/DotNetEditorPlugin.cs

@@ -243,11 +243,11 @@ protected override void _EnterTree()
 
         if (File.Exists(EditorPath.ProjectCSProjPath))
         {
-            var efs = EditorInterface.Singleton.GetResourceFilesystem();
-            efs.Connect(EditorFileSystem.SignalName.FilesystemChanged, Callable.From(RunUpgradeAssistant), (uint)ConnectFlags.OneShot);
+            RunUpgradeAssistant();
         }
         else
         {
+            EditorInternal.EditorResumeStartupSceneOpening();
             _msbuildPanel.Close();
             _toolBarBuildButton.Hide();
         }
@@ -364,6 +364,22 @@ private void UpdateWorkspaceProjectPath()
     }
 
     private void RunUpgradeAssistant()
+    {
+        var efs = EditorInterface.Singleton.GetResourceFilesystem();
+        if (efs.IsScanning())
+        {
+            // If the filesystem is still scanning, we delay running the upgrade assistant
+            // until it's done so we know the scenes and resources are ready.
+            efs.Connect(EditorFileSystem.SignalName.FilesystemChanged, Callable.From(RunUpgradeAssistantCore), (uint)ConnectFlags.OneShot);
+        }
+        else
+        {
+            // Otherwise, we just run it directly.
+            RunUpgradeAssistantCore();
+        }
+    }
+
+    private void RunUpgradeAssistantCore()
     {
         if (!File.Exists(EditorPath.ProjectCSProjPath))
         {
@@ -399,6 +415,8 @@ private void RunUpgradeAssistant()
             // Unregister temporary classes in reverse order.
             GodotRegistry.UnregisterClass<ResourceFormatLoaderCSharpScript>();
             GodotRegistry.UnregisterClass<CSharpScript>();
+
+            EditorInternal.EditorResumeStartupSceneOpening();
         }
     }
 

src/Godot.EditorIntegration/Internals/EditorInternal.Functions.cs

@@ -95,6 +95,14 @@ public static void StatusPanelSetContent(Control? content)
         _status_panel_set_content(content?.NativePtr ?? 0);
     }
 
+    private static delegate* unmanaged[Cdecl]<void> _editor_resume_startup_scene_opening;
+
+    public static void EditorResumeStartupSceneOpening()
+    {
+        Debug.Assert(_editor_resume_startup_scene_opening is not null);
+        _editor_resume_startup_scene_opening();
+    }
+
     private static delegate* unmanaged[Cdecl]<NativeGodotString*, void> _get_editor_assemblies_path;
 
     public static string GetEditorAssembliesPath()

src/Godot.EditorIntegration/Internals/EditorInternal.cs

@@ -25,6 +25,7 @@ public static unsafe void Initialize(nint getProcAddress)
         _status_indicator_notify_state_changed = (delegate* unmanaged[Cdecl]<void>)LoadProcAddress("status_indicator_notify_state_changed"u8);
         _status_indicator_update_severity = (delegate* unmanaged[Cdecl]<long, void>)LoadProcAddress("status_indicator_update_severity"u8);
         _status_panel_set_content = (delegate* unmanaged[Cdecl]<nint, void>)LoadProcAddress("status_panel_set_content"u8);
+        _editor_resume_startup_scene_opening = (delegate* unmanaged[Cdecl]<void>)LoadProcAddress("editor_resume_startup_scene_opening"u8);
         _get_editor_assemblies_path = (delegate* unmanaged[Cdecl]<NativeGodotString*, void>)LoadProcAddress("get_editor_assemblies_path"u8);
         _get_project_assemblies_path = (delegate* unmanaged[Cdecl]<NativeGodotString*, void>)LoadProcAddress("get_project_assemblies_path"u8);
         _get_project_output_path = (delegate* unmanaged[Cdecl]<NativeGodotString*, NativeGodotString*, void>)LoadProcAddress("get_project_output_path"u8);