Harden safe area state transitions

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: de9c7c01-82c4-42fd-9ab7-882279aadd15

Author: Copilot CI

.github/agents/maui-expert-reviewer.md

@@ -286,7 +286,7 @@ Safe area adjustments, keyboard insets, and ancestor hierarchy walks. See `safe-
 - CHECK: Prefer a capability-oriented contract such as `ISafeAreaElement` over publishing a numbered interface
 
 #### Platform notes
-- **iOS/MacCatalyst**: See `safe-area-ios.instructions.md` for `IsParentHandlingSafeArea`, `EqualsAtPixelLevel`, and the Window Guard anti-pattern. macCatalyst defaults `UseSafeArea` to `true` (unlike iOS where it's `false`).
+- **iOS/MacCatalyst**: See `safe-area-ios.instructions.md` for `GetParentHandledSafeAreaEdges`, `EqualsAtPixelLevel`, and the Window Guard anti-pattern. macCatalyst defaults `UseSafeArea` to `true` (unlike iOS where it's `false`).
 - **Android**: `WindowInsetsCompat` for keyboard and system bar; `fitsSystemWindows` behavior differs by API level
 
 ### 16. Complexity Reduction `[minor]`

.github/instructions/safe-area-ios.instructions.md

@@ -23,7 +23,7 @@ Local macOS 26+ testing does NOT validate CI behavior. Fixes must pass CI on mac
 
 ## Architecture (PR #34024)
 
-**`IsParentHandlingSafeArea`** — before applying adjustments, `MauiView`/`MauiScrollView` walk ancestors to check if any ancestor handles the **same edges**. If so, descendant skips (avoids double-padding). Edge-aware: parent handling `Top` does not block child handling `Bottom`. Result cached in `bool? _parentHandlesSafeArea`; cleared on `SafeAreaInsetsDidChange`, `InvalidateSafeArea`, `MovedToWindow`. `AppliesSafeAreaAdjustments` is `internal` for cross-type ancestor checks.
+**`GetParentHandledSafeAreaEdges`** — before applying adjustments, `MauiView`/`MauiScrollView` walk ancestors and resolve each ancestor's current safe-area inputs. Descendants suppress only overlapping edges, so a parent handling `Top` does not block a child handling `Bottom`. Results are cached in `SafeAreaEdges? _parentHandledSafeAreaEdges`; `SafeAreaInsetsDidChange`, `InvalidateSafeArea`, and `MovedToWindow` clear the cache. Property and keyboard changes call `MauiView.InvalidateSafeArea(UIView)` to invalidate the full native subtree.
 
 **`EqualsAtPixelLevel`** — safe area compared at device-pixel resolution to absorb sub-pixel animation noise (`0.0000001pt` during `TranslateToAsync`), preventing oscillation loops (#32586, #33934).
 

src/Controls/src/Core/BindableObject.cs

@@ -149,7 +149,8 @@ void ClearValueCore(BindableProperty property, SetterSpecificity specificity)
 			if (property.CoerceValue != null)
 				property.CoerceValue(this, newValue);
 
-			OnBindablePropertySet(property, original.Value, newValue, changed, changed);
+			var specificityChanged = original.Key != bpcontext.Values.GetSpecificity();
+			OnBindablePropertySet(property, original.Value, newValue, changed, changed, specificityChanged);
 		}
 
 		/// <summary>
@@ -680,6 +681,7 @@ void SetValueActual(BindableProperty property, BindablePropertyContext context,
 			}
 
 			context.Values.SetValue(specificity, value);
+			var specificityChanged = originalSpecificity != context.Values.GetSpecificity();
 
 			context.Attributes &= ~BindableContextAttributes.IsDefaultValueCreated;
 
@@ -697,15 +699,21 @@ void SetValueActual(BindableProperty property, BindablePropertyContext context,
 					_applying = false;
 				}
 
-				OnBindablePropertySet(property, original, value, !sameValue, true);
+				OnBindablePropertySet(property, original, value, !sameValue, true, specificityChanged);
 			}
 			else
 			{
-				OnBindablePropertySet(property, original, value, !sameValue, false);
+				OnBindablePropertySet(property, original, value, !sameValue, false, specificityChanged);
 			}
 		}
 
-		private protected virtual void OnBindablePropertySet(BindableProperty property, object original, object value, bool didChange, bool willFirePropertyChanged)
+		private protected virtual void OnBindablePropertySet(
+			BindableProperty property,
+			object original,
+			object value,
+			bool didChange,
+			bool willFirePropertyChanged,
+			bool specificityChanged)
 		{
 			if (willFirePropertyChanged)
 			{

src/Controls/src/Core/Border/Border.cs

@@ -469,17 +469,7 @@ void UpdateStrokeShape()
 		/// <inheritdoc cref="ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge"/>
 		SafeAreaRegions ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge(int edge)
 		{
-			// Use direct property
-			var regionForEdge = SafeAreaEdges.GetEdge(edge);
-
-			if (regionForEdge == SafeAreaRegions.Default)
-			{
-				// If no safe area edges are set, return None
-				return SafeAreaRegions.None;
-			}
-
-			// For Border, return as-is
-			return regionForEdge;
+			return SafeAreaViewStrategy.GetSafeAreaRegionsForElement((ISafeAreaElement)this, edge);
 		}
 
 		/// <inheritdoc cref="ISafeAreaElement.HasExplicitSafeAreaEdges"/>

src/Controls/src/Core/ContentPage/ContentPage.cs

@@ -173,36 +173,29 @@ Size IContentView.CrossPlatformMeasure(double widthConstraint, double heightCons
 		/// <inheritdoc cref="ISafeAreaElement.HasExplicitSafeAreaEdges"/>
 		bool ISafeAreaElement.HasExplicitSafeAreaEdges => SafeAreaElement.IsSafeAreaEdgesSet(this);
 
-		/// <inheritdoc cref="ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge"/>
-		SafeAreaRegions ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge(int edge)
+		/// <inheritdoc cref="ISafeAreaElement.SafeAreaEdges"/>
+		SafeAreaEdges ISafeAreaElement.SafeAreaEdges
 		{
-			// Check if the developer has explicitly set SafeAreaEdges
-			if (SafeAreaElement.IsSafeAreaEdgesSet(this))
+			get
 			{
-				// Developer has explicitly set SafeAreaEdges, use it directly
-				return SafeAreaEdges.GetEdge(edge);
-			}
-
+				var configuredEdges = SafeAreaEdges;
+				if (SafeAreaElement.IsSafeAreaEdgesSet(this))
+					return configuredEdges;
 
 #if IOS || MACCATALYST
-
-			// Developer hasn't set SafeAreaEdges, fall back to legacy IgnoreSafeArea behavior
-			var ignoreSafeArea = ((ISafeAreaView)this).IgnoreSafeArea;
-			if (ignoreSafeArea)
-			{
-				return SafeAreaRegions.None; // If legacy says "ignore", return None (edge-to-edge)
-			}
-			else
-			{
-				return SafeAreaRegions.Container; // If legacy says "don't ignore", return Container
-			}
-
+				return ((ISafeAreaView)this).IgnoreSafeArea
+					? SafeAreaEdges.None
+					: SafeAreaEdges.Container;
 #else
-
-			// Default to None (edge-to-edge) for consistent behavior across all platforms
-			return SafeAreaRegions.None;
-
+				return SafeAreaEdges.None;
 #endif
+			}
+		}
+
+		/// <inheritdoc cref="ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge"/>
+		SafeAreaRegions ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge(int edge)
+		{
+			return SafeAreaViewStrategy.GetSafeAreaRegionsForElement((ISafeAreaElement)this, edge);
 		}
 
 		SafeAreaEdges ISafeAreaElement.GetDefaultSafeAreaEdges()

src/Controls/src/Core/ContentView/ContentView.cs

@@ -94,17 +94,7 @@ private protected override string GetDebuggerDisplay()
 		/// <inheritdoc cref="ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge"/>
 		SafeAreaRegions ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge(int edge)
 		{
-			// Use direct property
-			var regionForEdge = SafeAreaEdges.GetEdge(edge);
-
-			if (regionForEdge == SafeAreaRegions.Default)
-			{
-				// If no safe area edges are set, return None
-				return SafeAreaRegions.None;
-			}
-
-			// For ContentView, return the region directly
-			return regionForEdge;
+			return SafeAreaViewStrategy.GetSafeAreaRegionsForElement((ISafeAreaElement)this, edge);
 		}
 	}
 }

src/Controls/src/Core/Element/Element.cs

@@ -691,16 +691,26 @@ protected virtual void OnParentSet()
 		}
 
 		HashSet<string> _pendingHandlerUpdatesFromBPSet = new HashSet<string>();
-		private protected override void OnBindablePropertySet(BindableProperty property, object original, object value, bool changed, bool willFirePropertyChanged)
+		private protected override void OnBindablePropertySet(
+			BindableProperty property,
+			object original,
+			object value,
+			bool changed,
+			bool willFirePropertyChanged,
+			bool specificityChanged)
 		{
 			if (willFirePropertyChanged)
 			{
 				_pendingHandlerUpdatesFromBPSet.Add(property.PropertyName);
 			}
 
-			base.OnBindablePropertySet(property, original, value, changed, willFirePropertyChanged);
+			base.OnBindablePropertySet(property, original, value, changed, willFirePropertyChanged, specificityChanged);
 			_pendingHandlerUpdatesFromBPSet.Remove(property.PropertyName);
-			UpdateHandlerValue(property.PropertyName, changed);
+			// Equal SafeAreaEdges values can still change setter specificity and Android listener eligibility.
+			var handlerValueChanged =
+				changed ||
+				(specificityChanged && ReferenceEquals(property, SafeAreaElement.SafeAreaEdgesProperty));
+			UpdateHandlerValue(property.PropertyName, handlerValueChanged);
 
 		}
 

src/Controls/src/Core/InputView/InputView.cs

@@ -315,9 +315,15 @@ string ITextInput.Text
 			set => SetValue(TextProperty, value, SetterSpecificity.FromHandler);
 		}
 
-		private protected override void OnBindablePropertySet(BindableProperty property, object original, object value, bool changed, bool willFirePropertyChanged)
+		private protected override void OnBindablePropertySet(
+			BindableProperty property,
+			object original,
+			object value,
+			bool changed,
+			bool willFirePropertyChanged,
+			bool specificityChanged)
 		{
-			base.OnBindablePropertySet(property, original, value, changed, willFirePropertyChanged);
+			base.OnBindablePropertySet(property, original, value, changed, willFirePropertyChanged, specificityChanged);
 
 			// When the same CursorPosition or SelectionLength value is re-set, the bindable property
 			// system detects no change (changed=false) and does not fire PropertyChanged, so the

src/Controls/src/Core/Layout/Layout.cs

@@ -415,33 +415,12 @@ private protected override string GetDebuggerDisplay()
 		/// <inheritdoc cref="ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge"/>
 		SafeAreaRegions ISafeAreaViewStrategy.GetSafeAreaRegionsForEdge(int edge)
 		{
-			// Use direct property first
-			var regionForEdge = SafeAreaEdges.GetEdge(edge);
-
-			if (regionForEdge == SafeAreaRegions.Default)
-			{
 #pragma warning disable CS0618 // Type or member is obsolete
-				if (IgnoreSafeArea)
-				{
-					return SafeAreaRegions.None;
-				}
-#pragma warning restore CS0618 // Type or member is obsolete
-
-				return SafeAreaRegions.Container;
-			}
-
-#pragma warning disable CS0618 // Type or member is obsolete
-			// By default this is false so if someone sets this to true, we return None for all edges
 			if (IgnoreSafeArea)
-			{
-				// If IgnoreSafeArea is set, we return None for all edges
 				return SafeAreaRegions.None;
-			}
 #pragma warning restore CS0618 // Type or member is obsolete
 
-			// For Layout views, never return the old Default - return None instead
-			// (since Default no longer exists in the new enum)
-			return regionForEdge;
+			return SafeAreaViewStrategy.GetSafeAreaRegionsForElement((ISafeAreaElement)this, edge);
 		}
 	}
 }

src/Controls/src/Core/SafeAreaElement.cs

@@ -43,6 +43,7 @@ static object SafeAreaEdgesDefaultValueCreator(BindableObject bindable)
 		/// <remarks>
 		/// The type must use <see cref="SafeAreaEdgesProperty"/> as the backing store for its safe area property.
 		/// </remarks>
+		/// <exception cref="ArgumentNullException">Thrown when <paramref name="bindable"/> is <see langword="null"/>.</exception>
 		public static bool IsSafeAreaEdgesSet(BindableObject bindable)
 		{
 			if (bindable is null)