Unreal Engine Issues and Bug Tracker (UE-149306)

Description

Assertion occurs when undoing a Child State's unparenting from another Child State.

Repro Rate: 5/5

Assertion failed: false [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\SListView.h] [Line: 831] 
STreeView<UStateTreeState*> [SStateTreeView.cpp(73)] detected a critical error. See diagnostic dump above. Provide a custom 'OnItemToString_Debug' for more detailed diagnostics.

After this occurs, a crash can also occur if the user had an invalid state and another state under that invalid state when the Assertion occurred. More info in the comments below!

Steps to Reproduce

Create a Blank BP project
Enable the StateTree plugin (Edit > Plugins)
Right-Click in Content Browser and create a new StateTree (Under AI > StateTree)
Right-Click on the Root StateTree and add a new Child State (Child1)
Add a new Child State to Child1 State (Child2)
Drag Child2 above Child1 to unparent it
Undo this action

Results: Assertion occurs, upon restarting the editor and trying to open the State Tree asset, the editor will crash.
Expected: No Assertion occurs and the user is able to open the State Tree asset without crashing.

*Crash can occur if there is a Child State inside of an Invalid State (And is saved) when the assertion occurs by undoing. See comments for more steps!

Callstack

– Assertion (After this Callstack is the Crash Callstack)

=== Critical error: ===

Assertion failed: false [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\SListView.h] [Line: 831] 
STreeView<UStateTreeState*> [SStateTreeView.cpp(73)] detected a critical error. See diagnostic dump above. Provide a custom 'OnItemToString_Debug' for more detailed diagnostics.


[Callstack] 0x00007ffba01db382 UnrealEditor-StateTreeEditorModule.dll!SListView<UStateTreeState *>::FWidgetGenerator::ValidateWidgetGeneration() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\SListView.h:831]
[Callstack] 0x00007ffba01c678e UnrealEditor-StateTreeEditorModule.dll!SListView<UStateTreeState *>::ReGenerateItems() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\SListView.h:1298]
[Callstack] 0x00007ffbf527728a UnrealEditor-Slate.dll!STableViewBase::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Views\STableViewBase.cpp:273]
[Callstack] 0x00007ffba01d641b UnrealEditor-StateTreeEditorModule.dll!STreeView<UStateTreeState *>::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\STreeView.h:587]
[Callstack] 0x00007ffbf4b07163 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1436]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b04565 UnrealEditor-SlateCore.dll!SOverlay::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SOverlay.cpp:200]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf5234a0e UnrealEditor-Slate.dll!SScrollBox::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Layout\SScrollBox.cpp:1090]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf51b5fe0 UnrealEditor-Slate.dll!SBorder::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Layout\SBorder.cpp:129]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b04565 UnrealEditor-SlateCore.dll!SOverlay::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SOverlay.cpp:200]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf523534c UnrealEditor-Slate.dll!SSplitter::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Layout\SSplitter.cpp:254]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf523534c UnrealEditor-Slate.dll!SSplitter::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Layout\SSplitter.cpp:254]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b04565 UnrealEditor-SlateCore.dll!SOverlay::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SOverlay.cpp:200]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf51b5fe0 UnrealEditor-Slate.dll!SBorder::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Layout\SBorder.cpp:129]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b04565 UnrealEditor-SlateCore.dll!SOverlay::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SOverlay.cpp:200]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf523534c UnrealEditor-Slate.dll!SSplitter::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Layout\SSplitter.cpp:254]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b04565 UnrealEditor-SlateCore.dll!SOverlay::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SOverlay.cpp:200]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08569 UnrealEditor-SlateCore.dll!SPanel::PaintArrangedChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:31]
[Callstack] 0x00007ffbf4b0470b UnrealEditor-SlateCore.dll!SPanel::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SPanel.cpp:12]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b04565 UnrealEditor-SlateCore.dll!SOverlay::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SOverlay.cpp:200]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b039cd UnrealEditor-SlateCore.dll!SCompoundWidget::OnPaint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SCompoundWidget.cpp:46]
[Callstack] 0x00007ffbf4b078e5 UnrealEditor-SlateCore.dll!SWidget::Paint() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWidget.cpp:1543]
[Callstack] 0x00007ffbf4b08684 UnrealEditor-SlateCore.dll!SWindow::PaintSlowPath() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWindow.cpp:2073]
[Callstack] 0x00007ffbf49ace1a UnrealEditor-SlateCore.dll!FSlateInvalidationRoot::PaintInvalidationRoot() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\FastUpdate\SlateInvalidationRoot.cpp:399]
[Callstack] 0x00007ffbf4b08945 UnrealEditor-SlateCore.dll!SWindow::PaintWindow() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Widgets\SWindow.cpp:2105]
[Callstack] 0x00007ffbf4f6904e UnrealEditor-Slate.dll!FSlateApplication::DrawWindowAndChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1106]
[Callstack] 0x00007ffbf4f694ca UnrealEditor-Slate.dll!FSlateApplication::DrawWindowAndChildren() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1158]
[Callstack] 0x00007ffbf4f94787 UnrealEditor-Slate.dll!FSlateApplication::PrivateDrawWindows() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1338]
[Callstack] 0x00007ffbf4f69b14 UnrealEditor-Slate.dll!FSlateApplication::DrawWindows() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1060]
[Callstack] 0x00007ffbf4fbaf99 UnrealEditor-Slate.dll!FSlateApplication::TickAndDrawWidgets() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1625]
[Callstack] 0x00007ffbf4fba728 UnrealEditor-Slate.dll!FSlateApplication::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1482]

– Crash that can occur after the Assertion is done if there is an invalid state w/child state in the State Tree

Error: === Critical error: ===
Error: 
Error: Fatal error!
Error: 
Error: Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000000000000d8
Error: 
Error: [Callstack] 0x00007ffba01f9d35 UnrealEditor-StateTreeEditorModule.dll!FStateTreeViewModel::GetExpandedStatesRecursive() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\StateTreeViewModel.cpp:305]
Error: [Callstack] 0x00007ffba0229e46 UnrealEditor-StateTreeEditorModule.dll!SStateTreeView::UpdateTree() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\SStateTreeView.cpp:206]
Error: [Callstack] 0x00007ffba01d8119 UnrealEditor-StateTreeEditorModule.dll!SStateTreeView::Construct() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\SStateTreeView.cpp:162]
Error: [Callstack] 0x00007ffba0224b70 UnrealEditor-StateTreeEditorModule.dll!FStateTreeEditor::SpawnTab_StateTreeView() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\StateTreeEditor.cpp:236]
Error: [Callstack] 0x00007ffba01ea857 UnrealEditor-StateTreeEditorModule.dll!TBaseSPMethodDelegateInstance<0,FStateTreeEditor,1,TSharedRef<SDockTab,1> __cdecl(FSpawnTabArgs const &),FDefaultDelegateUserPolicy>::Execute() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:290]
Error: [Callstack] 0x00007ffbf50882ad UnrealEditor-Slate.dll!FTabManager::SpawnTab() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1957]
Error: [Callstack] 0x00007ffbf507e2b4 UnrealEditor-Slate.dll!FTabManager::RestoreArea_Helper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1627]
Error: [Callstack] 0x00007ffbf5080bf2 UnrealEditor-Slate.dll!FTabManager::RestoreSplitterContent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1838]
Error: [Callstack] 0x00007ffbf5080098 UnrealEditor-Slate.dll!FTabManager::RestoreArea_Helper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1777]
Error: [Callstack] 0x00007ffbf5080bf2 UnrealEditor-Slate.dll!FTabManager::RestoreSplitterContent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1838]
Error: [Callstack] 0x00007ffbf507fd17 UnrealEditor-Slate.dll!FTabManager::RestoreArea_Helper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1756]
Error: [Callstack] 0x00007ffbf507d904 UnrealEditor-Slate.dll!FTabManager::RestoreArea() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:1551]
Error: [Callstack] 0x00007ffbf50806ef UnrealEditor-Slate.dll!FTabManager::RestoreFrom() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Docking\TabManager.cpp:995]
Error: [Callstack] 0x00007ffbd0c410ba UnrealEditor-UnrealEd.dll!SStandaloneAssetEditorToolkitHost::RestoreFromLayout() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Toolkits\SStandaloneAssetEditorToolkitHost.cpp:164]
Error: [Callstack] 0x00007ffbd0c4648b UnrealEditor-UnrealEd.dll!SStandaloneAssetEditorToolkitHost::SetupInitialContent() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Toolkits\SStandaloneAssetEditorToolkitHost.cpp:74]
Error: [Callstack] 0x00007ffbd0b6f4fd UnrealEditor-UnrealEd.dll!FAssetEditorToolkit::InitAssetEditor() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Toolkits\AssetEditorToolkit.cpp:263]
Error: [Callstack] 0x00007ffbd0b6f915 UnrealEditor-UnrealEd.dll!FAssetEditorToolkit::InitAssetEditor() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Toolkits\AssetEditorToolkit.cpp:62]
Error: [Callstack] 0x00007ffba0206887 UnrealEditor-StateTreeEditorModule.dll!FStateTreeEditor::InitEditor() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\StateTreeEditor.cpp:187]
Error: [Callstack] 0x00007ffba01e1909 UnrealEditor-StateTreeEditorModule.dll!FStateTreeEditorModule::CreateStateTreeEditor() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\StateTreeEditorModule.cpp:111]
Error: [Callstack] 0x00007ffba0213351 UnrealEditor-StateTreeEditorModule.dll!FAssetTypeActions_StateTree::OpenAssetEditor() [D:\build\++UE5\Sync\Engine\Plugins\Runtime\StateTree\Source\StateTreeEditorModule\Private\AssetTypeActions_StateTree.cpp:24]
Error: [Callstack] 0x00007ffbd0aeb433 UnrealEditor-UnrealEd.dll!UAssetEditorSubsystem::OpenEditorForAsset() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Subsystems\AssetEditorSubsystem.cpp:377]
Error: [Callstack] 0x00007ffbd0aebca9 UnrealEditor-UnrealEd.dll!UAssetEditorSubsystem::OpenEditorForAssets_Advanced() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Subsystems\AssetEditorSubsystem.cpp:451]
Error: [Callstack] 0x00007ffbd0aeba3a UnrealEditor-UnrealEd.dll!UAssetEditorSubsystem::OpenEditorForAssets() [D:\build\++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Subsystems\AssetEditorSubsystem.cpp:567]
Error: [Callstack] 0x00007ffb9a420805 UnrealEditor-ContentBrowserAssetDataSource.dll!ContentBrowserAssetData::EditOrPreviewAssetFileItems() [D:\build\++UE5\Sync\Engine\Plugins\Editor\ContentBrowser\ContentBrowserAssetDataSource\Source\ContentBrowserAssetDataSource\Private\ContentBrowserAssetDataCore.cpp:270]
Error: [Callstack] 0x00007ffb9a420a60 UnrealEditor-ContentBrowserAssetDataSource.dll!ContentBrowserAssetData::EditOrPreviewItems() [D:\build\++UE5\Sync\Engine\Plugins\Editor\ContentBrowser\ContentBrowserAssetDataSource\Source\ContentBrowserAssetDataSource\Private\ContentBrowserAssetDataCore.cpp:290]
Error: [Callstack] 0x00007ffb9a409aff UnrealEditor-ContentBrowserAssetDataSource.dll!UContentBrowserAssetDataSource::BulkEditItems() [D:\build\++UE5\Sync\Engine\Plugins\Editor\ContentBrowser\ContentBrowserAssetDataSource\Source\ContentBrowserAssetDataSource\Private\ContentBrowserAssetDataSource.cpp:1228]
Error: [Callstack] 0x00007ffbb06020f0 UnrealEditor-ContentBrowser.dll!SContentBrowser::OnItemsActivated() [D:\build\++UE5\Sync\Engine\Source\Editor\ContentBrowser\Private\SContentBrowser.cpp:2680]
Error: [Callstack] 0x00007ffbb05bb010 UnrealEditor-ContentBrowser.dll!TBaseSPMethodDelegateInstance<0,SContentBrowser,1,void __cdecl(TArrayView<FContentBrowserItem const ,int>,enum EAssetTypeActivationMethod::Type),FDefaultDelegateUserPolicy>::Execute() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:290]
Error: [Callstack] 0x00007ffbb06044db UnrealEditor-ContentBrowser.dll!SAssetView::OnListMouseButtonDoubleClick() [D:\build\++UE5\Sync\Engine\Source\Editor\ContentBrowser\Private\SAssetView.cpp:3658]
Error: [Callstack] 0x00007ffbb05c2c36 UnrealEditor-ContentBrowser.dll!TBaseSPMethodDelegateInstance<0,SAssetView,1,void __cdecl(TSharedPtr<FAssetViewItem,1>),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:307]
Error: [Callstack] 0x00007ffbb0548802 UnrealEditor-ContentBrowser.dll!TDelegate<void __cdecl(TSharedPtr<FAssetViewItem,1>),FDefaultDelegateUserPolicy>::ExecuteIfBound<void,0>() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:607]
Error: [Callstack] 0x00007ffbb061767d UnrealEditor-ContentBrowser.dll!SListView<TSharedPtr<FAssetViewItem,1> >::Private_OnItemDoubleClicked() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\SListView.h:1087]
Error: [Callstack] 0x00007ffbb06048a2 UnrealEditor-ContentBrowser.dll!STableRow<TSharedPtr<FAssetViewItem,1> >::OnMouseButtonDoubleClick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Public\Widgets\Views\STableRow.h:398]
Error: [Callstack] 0x00007ffbf4f3601e UnrealEditor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FPointerEvent,<lambda_be18c20258355610e1a03a230227eebb> >() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:405]
Error: [Callstack] 0x00007ffbf4fae866 UnrealEditor-Slate.dll!FSlateApplication::RoutePointerDoubleClickEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5420]
Error: [Callstack] 0x00007ffbf4f98249 UnrealEditor-Slate.dll!FSlateApplication::ProcessMouseButtonDoubleClickEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5405]
Error: [Callstack] 0x00007ffbf4f8cea1 UnrealEditor-Slate.dll!FSlateApplication::OnMouseDoubleClick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5368]
Error: [Callstack] 0x00007ffc1352a8f5 UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2214]
Error: [Callstack] 0x00007ffc13519247 UnrealEditor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2699]
Error: [Callstack] 0x00007ffc1352ce51 UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:1078]
Error: [Callstack] 0x00007ffc135149a7 UnrealEditor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:916]
Error: [Callstack] 0x00007ffc545363ed USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ffc545360be USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb96976552 InkObj.dll!UnknownFunction []
Error: [Callstack] 0x00007ffc3f981028 atlthunk.dll!UnknownFunction []
Error: [Callstack] 0x00007ffc545363ed USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ffc54535de2 USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ffc1352e148 UnrealEditor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:138]
Error: [Callstack] 0x00007ff777a17114 UnrealEditor.exe!FEngineLoop::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5139]
Error: [Callstack] 0x00007ff777a30d9c UnrealEditor.exe!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:183]
Error: [Callstack] 0x00007ff777a30e8a UnrealEditor.exe!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:147]
Error: [Callstack] 0x00007ff777a33c4d UnrealEditor.exe!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:283]
Error: [Callstack] 0x00007ff777a45534 UnrealEditor.exe!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:330]
Error: [Callstack] 0x00007ff777a486e6 UnrealEditor.exe!__scrt_common_main_seh() [d:\a01\_work\6\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
Error: [Callstack] 0x00007ffc536d7bd4 KERNEL32.DLL!UnknownFunction []
Error: [Callstack] 0x00007ffc5504ced1 ntdll.dll!UnknownFunction []

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Fixed

Component	UE - AI - StateTree
Affects Versions	5.0
Target Fix	5.0.2

Fix Commit	19847563
Main Commit	19853233

Created	Apr 15, 2022
Resolved	Apr 21, 2022
Updated	May 6, 2022

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UE-149306

Assertion occurs when undoing a Child State's unparenting from another Child State in AI State Trees, leading to a crash.

Assertion occurs when undoing a Child State's unparenting from another Child State in AI State Trees, leading to a crash.

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