WIP: Hackfix for #9007

src/Avalonia.Base/PropertyStore/FramePriority.cs

@@ -1,4 +1,5 @@
-using System.Diagnostics;
+using System;
+using System.Diagnostics;
 using Avalonia.Data;
 
 namespace Avalonia.PropertyStore
@@ -8,12 +9,15 @@ namespace Avalonia.PropertyStore
         Animation,
         AnimationTemplatedParentTheme,
         AnimationTheme,
-        StyleTrigger,
-        StyleTriggerTemplatedParentTheme,
-        StyleTriggerTheme,
+        TemplateStyleTrigger,
+        TemplateStyleTriggerTemplatedParentTheme,
+        TemplateStyleTriggerTheme,
         Template,
         TemplateTemplatedParentTheme,
         TemplateTheme,
+        StyleTrigger,
+        StyleTriggerTemplatedParentTheme,
+        StyleTriggerTheme,
         Style,
         StyleTemplatedParentTheme,
         StyleTheme,
@@ -21,11 +25,21 @@ namespace Avalonia.PropertyStore
 
     internal static class FramePriorityExtensions
     {
-        public static FramePriority ToFramePriority(this BindingPriority priority, FrameType type = FrameType.Style)
+        public static FramePriority ToFramePriority(
+            this BindingPriority priority,
+            FrameType type = FrameType.Style,
+            bool isTemplateSelector = false)
         {
-            Debug.Assert(priority != BindingPriority.LocalValue);
-            var p = (int)(priority > 0 ? priority : priority + 1);
-            return (FramePriority)(p * 3 + (int)type);
+            var p = (priority, isTemplateSelector) switch
+            {
+                (BindingPriority.Animation, _) => FramePriority.Animation,
+                (BindingPriority.StyleTrigger, false) => FramePriority.StyleTrigger,
+                (BindingPriority.StyleTrigger, true) => FramePriority.TemplateStyleTrigger,
+                (BindingPriority.Template, _) => FramePriority.StyleTrigger,
+                (BindingPriority.Style, _) => FramePriority.Style,
+                _ => throw new ArgumentException("Invalid priority."),
+            };
+            return (FramePriority)((int)p + (int)type);
         }
 
         public static bool IsType(this FramePriority priority, FrameType type)

src/Avalonia.Base/PropertyStore/ValueFrame.cs

@@ -20,10 +20,10 @@ namespace Avalonia.PropertyStore
         private ValueStore? _owner;
         private bool _isShared;
 
-        protected ValueFrame(BindingPriority priority, FrameType type)
+        protected ValueFrame(BindingPriority priority, FrameType type, bool isTemplateSelector = false)
         {
             Priority = priority;
-            FramePriority = priority.ToFramePriority(type);
+            FramePriority = priority.ToFramePriority(type, isTemplateSelector);
         }
 
         public int EntryCount => _index.Count;

src/Avalonia.Base/PropertyStore/ValueStore.cs

@@ -772,7 +772,7 @@ namespace Avalonia.PropertyStore
             Debug.Assert(oldValue != newValue);
             Debug.Assert(oldValue is not null || newValue is not null);
 
-            // If the value is set locally, propagaton ends here.
+            // If the value is set locally, propagation ends here.
             if (_effectiveValues.ContainsKey(property) == true)
                 return;
 
@@ -825,7 +825,7 @@ namespace Avalonia.PropertyStore
                     if (current?.Priority < priority && current?.BasePriority < priority)
                         break;
 
-                    // Try to get an entry from the frame for the property we're reevaluating.
+                    // Try to get an entry from the frame for the property we're re-evaluating.
                     var foundEntry = frame.TryGetEntryIfActive(property, out var entry, out var activeChanged);
                     
                     // If the active state of the frame has changed since the last read, and
@@ -855,6 +855,9 @@ namespace Avalonia.PropertyStore
                             AddEffectiveValue(property, current);
                             current.SetAndRaise(this, entry, priority);
                         }
+
+                        if (priority > BindingPriority.Animation)
+                            break;
                     }
 
                     if (generation != _frameGeneration)

src/Avalonia.Base/Styling/ControlTheme.cs

@@ -48,7 +48,7 @@ namespace Avalonia.Styling
 
             if (HasSettersOrAnimations && TargetType.IsAssignableFrom(StyledElement.GetStyleKey(target)))
             {
-                Attach(target, null, type);
+                Attach(target, null, type, false);
                 return SelectorMatchResult.AlwaysThisType;
             }
 

src/Avalonia.Base/Styling/Style.cs

@@ -74,7 +74,7 @@ namespace Avalonia.Styling
 
                 if (match.IsMatch)
                 {
-                    Attach(target, match.Activator, type);
+                    Attach(target, match.Activator, type, Selector?.InTemplate ?? false);
                 }
 
                 result = match.Result;

src/Avalonia.Base/Styling/StyleBase.cs

@@ -92,7 +92,7 @@ namespace Avalonia.Styling
             return false;
         }
 
-        internal ValueFrame Attach(StyledElement target, IStyleActivator? activator, FrameType type)
+        internal ValueFrame Attach(StyledElement target, IStyleActivator? activator, FrameType type, bool isTemplateSelector)
         {
             if (target is not AvaloniaObject ao)
                 throw new InvalidOperationException("Styles can only be applied to AvaloniaObjects.");
@@ -107,7 +107,7 @@ namespace Avalonia.Styling
             {
                 var canShareInstance = activator is null;
 
-                instance = new StyleInstance(this, activator, type);
+                instance = new StyleInstance(this, activator, type, isTemplateSelector);
 
                 if (_setters is not null)
                 {

src/Avalonia.Base/Styling/StyleInstance.cs

@@ -29,8 +29,9 @@ namespace Avalonia.Styling
         public StyleInstance(
             IStyle style,
             IStyleActivator? activator,
-            FrameType type)
-            : base(GetPriority(activator), type)
+            FrameType type,
+            bool isTemplateSelector)
+            : base(GetPriority(activator), type, isTemplateSelector)
         {
             _activator = activator;
             Source = style;

tests/Avalonia.Base.UnitTests/PropertyStore/ValueStoreTests_Frames.cs

@@ -117,7 +117,7 @@ namespace Avalonia.Base.UnitTests.PropertyStore
 
         private static StyleInstance InstanceStyle(Style style, StyledElement target)
         {
-            var result = new StyleInstance(style, null, FrameType.Style);
+            var result = new StyleInstance(style, null, FrameType.Style, false);
 
             foreach (var setter in style.Setters)
                 result.Add(setter.Instance(result, target));

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/ControlTemplateTests.cs

@@ -5,6 +5,7 @@ using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Data;
 using Avalonia.Diagnostics;
+using Avalonia.Layout;
 using Avalonia.Markup.Xaml.Templates;
 using Avalonia.Media;
 using Avalonia.UnitTests;
@@ -246,6 +247,41 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             }
         }
 
+        [Fact]
+        public void Foo()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
+    <Window.Resources>
+        <ControlTheme x:Key='{x:Type Button}' TargetType='Button'>
+			<Style Selector='^:disabled'>
+				<Setter Property='Background' Value='LightGray'/>
+			</Style>
+		</ControlTheme>
+    </Window.Resources>
+
+    <TemplatedControl Background='LightBlue' IsEnabled='False'>
+		<TemplatedControl.Template>
+			<ControlTemplate TargetType='TemplatedControl'>
+				<Button Background='{TemplateBinding Background}'/>
+			</ControlTemplate>
+		</TemplatedControl.Template>
+	</TemplatedControl>
+</Window>";
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                window.Show();
+
+                var control = (TemplatedControl)window.Content;
+                var button = Assert.IsType<Button>(control.GetVisualChildren().Single());
+                var brush = Assert.IsAssignableFrom<ISolidColorBrush>(button.Background);
+
+                Assert.Equal(Colors.LightBlue, brush.Color);
+            }
+        }
+
         [Fact]
         public void ControlTemplate_With_Nested_Child_Is_Operational()
         {