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fix(AdornerLayer): remove dead _layoutDirty infrastructure (CS0414) #7

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Merged
oysteinkrog merged 1 commit into from
May 17, 2026
+1 −72
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fix(AdornerLayer): remove dead _layoutDirty infrastructure (CS0414) #7

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73 changes: 1 addition & 72 deletions src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/AdornerLayer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -232,14 +232,6 @@ public void Remove(Adorner adorner)
RemoveAdornerInfo(_zOrderMap, adorner, adornerInfo.ZOrder);
_children.Remove(adorner);
RemoveLogicalChild(adorner);

// If no more adorners remain for this element, unsubscribe from its LayoutUpdated
// to break the AdornerLayer/UIElement retention cycle.
if (ElementMap[adorner.AdornedElement] == null)
{
UnsubscribeFromElementLayout(adorner.AdornedElement);
}
_layoutDirty = true;
}

/// <summary>
Expand All @@ -261,7 +253,6 @@ public void Update()
}
}

_layoutDirty = true;
UpdateAdorner(null);
}

Expand All @@ -285,7 +276,6 @@ public void Update(UIElement element)
InvalidateAdorner((AdornerInfo)adornerInfos[i++]);
}

_layoutDirty = true;
UpdateAdorner(element);
}

Expand Down Expand Up @@ -612,15 +602,10 @@ internal void Add(Adorner adorner, int zOrder)

AddAdornerInfo(ElementMap, adornerInfo, adorner.AdornedElement);

// Subscribe to the adorned element's LayoutUpdated so we can arm _layoutDirty
// only when something actually changes, rather than on every layer-level fire.
SubscribeToElementLayout(adorner.AdornedElement);

AddAdornerToVisualTree(adornerInfo, zOrder);

AddLogicalChild(adorner);

_layoutDirty = true;
UpdateAdorner(adorner.AdornedElement);
}

Expand All @@ -639,18 +624,6 @@ internal static void InvalidateAdorner(AdornerInfo adornerInfo)
adornerInfo.SimpleTransform = default;
}

// TODO: regression tests for OnLayoutUpdated fast path (no DRT harness available in fork):
// 1. EmptyAdornerLayer_OnLayoutUpdated_DoesNotCallUpdateAdorner
// Create an AdornerLayer, call OnLayoutUpdated — verify UpdateAdorner was NOT called
// (mock or subclass override) and _layoutDirty ends up false.
// 2. AdornerLayer_AddAdornerAfterIdle_TriggersUpdateAdorner
// Create empty layer, fire OnLayoutUpdated (empty fast-path, _layoutDirty→false),
// Add() an adorner, fire OnLayoutUpdated again — verify UpdateAdorner IS called.
// 3. AdornerLayer_AddRemoveDuringLayoutUpdated_NoStaleDirtyFlag
// Simulate Add() inside a LayoutUpdated handler that fires concurrently with the
// layer's own handler; confirm that by the time the next pass fires, the adorner
// is walked (ElementMap.Count > 0 path) and _layoutDirty is not stranded false.

/// <summary>
/// OnLayoutUpdated event handler
/// </summary>
Expand All @@ -670,7 +643,7 @@ internal void OnLayoutUpdated(object sender, EventArgs args)
return;
}

// Non-empty layer: always run UpdateAdorner. A cached _layoutDirty flag
// Non-empty layer: always run UpdateAdorner. A cached dirty flag
// cannot comprehensively observe every coordinate-space change that
// requires re-walking adorners (ancestor RenderTransform changes,
// ContentPresenter re-templating that swaps the subtree between an
Expand All @@ -682,40 +655,6 @@ internal void OnLayoutUpdated(object sender, EventArgs args)
UpdateAdorner(null);
}

/// <summary>
/// LayoutUpdated handler subscribed per adorned element.
/// Arms the layer-level dirty bit so the next OnLayoutUpdated fires UpdateAdorner.
/// </summary>
private void OnAdornedElementLayoutUpdated(object sender, EventArgs e)
{
_layoutDirty = true;
}

/// <summary>
/// Subscribe to LayoutUpdated on the given element exactly once (tracked via
/// _subscribedElements). Called when the first adorner is registered for an element.
/// </summary>
private void SubscribeToElementLayout(UIElement element)
{
_subscribedElements ??= new HashSet<UIElement>();
if (_subscribedElements.Add(element))
{
element.LayoutUpdated += OnAdornedElementLayoutUpdated;
}
}

/// <summary>
/// Unsubscribe from LayoutUpdated on the given element.
/// Called when the last adorner for an element is removed.
/// </summary>
private void UnsubscribeFromElementLayout(UIElement element)
{
if (_subscribedElements != null && _subscribedElements.Remove(element))
{
element.LayoutUpdated -= OnAdornedElementLayoutUpdated;
}
}

/// <summary>
/// Set the zOrder on the given adorner.
/// </summary>
Expand All @@ -739,7 +678,6 @@ internal void SetAdornerZOrder(Adorner adorner, int zOrder)
adornerInfo.ZOrder = zOrder;
AddAdornerToVisualTree(adornerInfo, zOrder);
InvalidateAdorner(adornerInfo);
_layoutDirty = true;
UpdateAdorner(adorner.AdornedElement);
}

Expand Down Expand Up @@ -1264,15 +1202,6 @@ private GeneralTransform GetProposedTransform(Adorner adorner, GeneralTransform
// re-enter this same AdornerLayer cannot clobber an outer pass's snapshot.
private object[] _zOrderValuesSnapshotBuffer;

// Dirty-bit gate for OnLayoutUpdated. Set on adorner add/remove and on any
// per-element LayoutUpdated event; cleared at the top of UpdateAdorner so a
// re-entrant fire during the walk re-arms for the next pass.
// Starts true so the very first layout pass is never skipped.
private bool _layoutDirty = true;
// Set of elements for which we have a LayoutUpdated subscription.
// Maintained to ensure subscribe/unsubscribe are balanced.
private HashSet<UIElement> _subscribedElements;

#endregion Private Fields
}
}
Expand Down
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