Fix 54334 (#855)

* [C] unset the FromStyle flag on manual setting

* [C] Do not reset overriden values to default

* complete the fix

Xamarin.Forms.Core.UnitTests/StyleTests.cs

@@ -8,12 +8,19 @@ namespace Xamarin.Forms.Core.UnitTests
 	public class StyleTests : BaseTestFixture
 	{
 		[SetUp]
-		public void Setup ()
+		public override void Setup ()
 		{
 			base.Setup ();
 			Device.PlatformServices = new MockPlatformServices ();
 		}
 
+		[TearDown]
+		public override void TearDown()
+		{
+			base.TearDown();
+			Application.Current = null;
+		}
+
 		[Test]
 		public void ApplyUnapplyStyle ()
 		{
@@ -703,5 +710,54 @@ namespace Xamarin.Forms.Core.UnitTests
 			Assert.AreEqual (Color.Pink, button.TextColor);
 			Assert.AreEqual (20d, button.FontSize);
 		}
+
+		[Test]
+		public void ReplacingResourcesDoesNotOverrideManuallySetProperties()
+		{
+			var label0 = new Label {
+				TextColor = Color.Pink
+			};
+			var label1 = new Label();
+
+			Assume.That(label0.TextColor, Is.EqualTo(Color.Pink));
+			Assume.That(label1.TextColor, Is.EqualTo(Color.Default));
+
+			var rd0 = new ResourceDictionary {
+				new Style (typeof(Label)) {
+					Setters = {
+						new Setter {Property = Label.TextColorProperty, Value = Color.Olive}
+					}
+				}
+			};
+			var rd1 = new ResourceDictionary {
+				new Style (typeof(Label)) {
+					Setters = {
+						new Setter {Property = Label.TextColorProperty, Value = Color.Lavender}
+					}
+				}
+			};
+
+			var mockApp = new MockApplication();
+			Application.Current = mockApp;
+			mockApp.Resources = rd0;
+
+			var layout = new StackLayout { 
+				Children = {
+					label0,
+					label1,
+				}
+			};
+
+			mockApp.MainPage = new ContentPage { Content = layout};
+			//Assert.That(label0.TextColor, Is.EqualTo(Color.Pink));
+			//Assert.That(label1.TextColor, Is.EqualTo(Color.Default));
+
+			Assert.That(label0.TextColor, Is.EqualTo(Color.Pink));
+			Assert.That(label1.TextColor, Is.EqualTo(Color.Olive));
+
+			mockApp.Resources = rd1;
+			Assert.That(label0.TextColor, Is.EqualTo(Color.Pink));
+			Assert.That(label1.TextColor, Is.EqualTo(Color.Lavender));
+		}
 	}
 }

Xamarin.Forms.Core/BindableObject.cs

@@ -363,9 +363,10 @@ namespace Xamarin.Forms
 				value = property.CoerceValue(this, value);
 
 			BindablePropertyContext context = GetOrCreateContext(property);
-			if (manuallySet)
+			if (manuallySet) {
 				context.Attributes |= BindableContextAttributes.IsManuallySet;
-			else
+				context.Attributes &= ~BindableContextAttributes.IsSetFromStyle;
+			} else
 				context.Attributes &= ~BindableContextAttributes.IsManuallySet;
 
 			if (fromStyle)

Xamarin.Forms.Core/Setter.cs

@@ -63,12 +63,12 @@ namespace Xamarin.Forms
 		internal void UnApply(BindableObject target, bool fromStyle = false)
 		{
 			if (target == null)
-				throw new ArgumentNullException("target");
+				throw new ArgumentNullException(nameof(target));
 			if (Property == null)
 				return;
 
 			object actual = target.GetValue(Property);
-			if (!fromStyle && !Equals(actual, Value))
+			if (!Equals(actual, Value) && !(Value is Binding) && !(Value is DynamicResource))
 			{
 				//Do not reset default value if the value has been changed
 				_originalValues.Remove(target);

Xamarin.Forms.Xaml.UnitTests/Issues/Bz28719.xaml.cs

@@ -44,10 +44,10 @@ namespace Xamarin.Forms.Xaml.UnitTests
 				Assert.NotNull (image0);
 
 				cell0.BindingContext = new {IsSelected = true};
-				Assert.AreEqual ("Remove.png", (image0.Source as FileImageSource).File);
+				Assert.AreEqual ("Remove.png", (image0.Source as FileImageSource)?.File);
 
 				cell0.BindingContext = new {IsSelected = false};
-				Assert.AreEqual ("Add.png", (image0.Source as FileImageSource).File);
+				Assert.AreEqual ("Add.png", (image0.Source as FileImageSource)?.File);
 
 				var cell1 = template.CreateContent () as ViewCell;
 				Assert.NotNull (cell1);
@@ -55,10 +55,10 @@ namespace Xamarin.Forms.Xaml.UnitTests
 				Assert.NotNull (image1);
 
 				cell1.BindingContext = new {IsSelected = true};
-				Assert.AreEqual ("Remove.png", (image1.Source as FileImageSource).File);
+				Assert.AreEqual ("Remove.png", (image1.Source as FileImageSource)?.File);
 
 				cell1.BindingContext = new {IsSelected = false};
-				Assert.AreEqual ("Add.png", (image1.Source as FileImageSource).File);
+				Assert.AreEqual ("Add.png", (image1.Source as FileImageSource)?.File);
 			}
 		}
 	}

Xamarin.Forms.Xaml.UnitTests/Issues/Bz41048.xaml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage
+	xmlns="http://xamarin.com/schemas/2014/forms"
+	xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+	x:Class="Xamarin.Forms.Xaml.UnitTests.Bz41048">
+	<ContentPage.Resources>
+		<ResourceDictionary>
+			<!-- Standard Style -->
+			<Style x:Key="StandardLabelStyle" TargetType="Label">
+				<Setter Property="TextColor" Value="Red"/>
+				<Setter Property="LineBreakMode" Value="TailTruncation"/>
+			</Style>
+
+			<!-- Derived style with bold font -->
+			<Style x:Key="StandarBoldLabelStyle" TargetType="Label" BasedOn="{StaticResource StandardLabelStyle}">
+				<Setter Property="FontAttributes" Value="Bold"/>
+			</Style>
+			
+			<!-- Use the StandardLabelStyle as implicit style for all labels -->
+			<Style TargetType="Label" BasedOn="{StaticResource StandardLabelStyle}"/>
+		</ResourceDictionary>
+	</ContentPage.Resources>
+	<Label x:Name="label0"
+		Style="{StaticResource StandarBoldLabelStyle}"
+		LineBreakMode="WordWrap" />
+</ContentPage>

Xamarin.Forms.Xaml.UnitTests/Issues/Bz41048.xaml.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using NUnit.Framework;
+using Xamarin.Forms;
+using Xamarin.Forms.Core.UnitTests;
+
+namespace Xamarin.Forms.Xaml.UnitTests
+{
+	public partial class Bz41048 : ContentPage
+	{
+		public Bz41048()
+		{
+			InitializeComponent();
+		}
+
+		public Bz41048(bool useCompiledXaml)
+		{
+			//this stub will be replaced at compile time
+		}
+
+		[TestFixture]
+		class Tests
+		{
+			[SetUp]
+			public void Setup()
+			{
+				Device.PlatformServices = new MockPlatformServices();
+			}
+
+			[TearDown]
+			public void TearDown()
+			{
+				Application.Current = null;
+				Device.PlatformServices = null;
+			}
+
+			[TestCase(true)]
+			[TestCase(false)]
+			public void StyleDoesNotOverrideValues(bool useCompiledXaml)
+			{
+				var layout = new Bz41048(useCompiledXaml);
+				var label = layout.label0;
+				Assert.That (label.TextColor, Is.EqualTo(Color.Red));
+				Assert.That (label.FontAttributes, Is.EqualTo(FontAttributes.Bold));
+				Assert.That (label.LineBreakMode, Is.EqualTo(LineBreakMode.WordWrap));
+			}
+		}
+	}
+}

Xamarin.Forms.Xaml.UnitTests/Issues/Bz54334.xaml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="Xamarin.Forms.Xaml.UnitTests.Bz54334">
+<StackLayout Padding="10">
+        <Label x:Name="label" HorizontalTextAlignment="Center" Text="I have a set textcolor, but in since pre-3 styles will override it.."  TextColor="Black" />
+        <Label x:Name="themedLabel" HorizontalTextAlignment="Center" Text="I dont have a set textcolor, syles can override me as much as they want"   />
+        <Button x:Name="btn" Text="Change Theme"></Button>
+    </StackLayout>
+</ContentPage>

Xamarin.Forms.Xaml.UnitTests/Issues/Bz54334.xaml.cs

@@ -0,0 +1,96 @@
+using System;
+using System.Collections.Generic;
+using NUnit.Framework;
+using Xamarin.Forms;
+using Xamarin.Forms.Core.UnitTests;
+
+namespace Xamarin.Forms.Xaml.UnitTests
+{
+	public class Bz54334App : Application
+	{
+		bool daymode = true;
+		public Bz54334App(bool useCompiledXaml)
+		{
+			Resources = new ResourceDictionary{
+				new Style(typeof(Label)) {
+					Setters = {
+						new Setter {Property = Label.TextColorProperty, Value=Color.Blue}
+					}
+				}
+			};
+			MainPage = new Bz54334(useCompiledXaml);
+			MessagingCenter.Subscribe<ContentPage>(this, "ChangeTheme", (s) => {
+				ToggleTheme();
+			});
+		}
+
+		void ToggleTheme()
+		{
+			Resources = daymode ? new ResourceDictionary{
+				new Style(typeof(Label)) {
+					Setters = {
+						new Setter {Property = Label.TextColorProperty, Value=Color.Red}
+					}
+				}
+			} : new ResourceDictionary{
+				new Style(typeof(Label)) {
+					Setters = {
+						new Setter {Property = Label.TextColorProperty, Value=Color.Blue}
+					}
+				}
+			};
+			daymode = !daymode;
+		}
+	}
+
+	public partial class Bz54334 : ContentPage
+	{
+		public Bz54334()
+		{
+			InitializeComponent();
+		}
+		public Bz54334(bool useCompiledXaml)
+		{
+			//this stub will be replaced at compile time
+		}
+
+		[TestFixture]
+		class Tests
+		{
+			[SetUp]
+			public void Setup()
+			{
+				Device.PlatformServices = new MockPlatformServices();
+			}
+
+			[TearDown]
+			public void TearDown()
+			{
+				Application.Current = null;
+				Device.PlatformServices = null;
+			}
+
+			[TestCase(true)]
+			[TestCase(false)]
+			public void Foo(bool useCompiledXaml)
+			{
+				var app = Application.Current = new Bz54334App(useCompiledXaml);
+				var page = app.MainPage as Bz54334;
+				var l0 = page.label;
+				var l1 = page.themedLabel;
+
+				Assert.That(l0.TextColor, Is.EqualTo(Color.Black));
+				Assert.That(l1.TextColor, Is.EqualTo(Color.Blue));
+
+				MessagingCenter.Send<ContentPage>(page, "ChangeTheme");
+				Assert.That(l0.TextColor, Is.EqualTo(Color.Black));
+				Assert.That(l1.TextColor, Is.EqualTo(Color.Red));
+
+				MessagingCenter.Send<ContentPage>(page, "ChangeTheme");
+				Assert.That(l0.TextColor, Is.EqualTo(Color.Black));
+				Assert.That(l1.TextColor, Is.EqualTo(Color.Blue));
+
+			}
+		}
+	}
+}

Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj

@@ -461,6 +461,12 @@
     <Compile Include="Issues\Bz53203.xaml.cs">
       <DependentUpon>Bz53203.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Issues\Bz54334.xaml.cs">
+      <DependentUpon>Bz54334.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="Issues\Bz41048.xaml.cs">
+      <DependentUpon>Bz41048.xaml</DependentUpon>
+    </Compile>
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <Import Project="..\.nuspec\Xamarin.Forms.Debug.targets" />
@@ -842,6 +848,12 @@
     <EmbeddedResource Include="Issues\Bz53203.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="Issues\Bz54334.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="Issues\Bz41048.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />