When AppContext switch caching is disabled, default switch value was …

…not stored, we were lucky with switches that have "false" as a default
dotnet · Nov 14, 2024 · 18e6274 · 18e6274
1 parent fd9aec1
commit 18e6274
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Showing 7 changed files with 117 additions and 54 deletions.
diff --git a/src/Common/tests/TestUtilities/AppContextSwitchNames.cs b/src/Common/tests/TestUtilities/AppContextSwitchNames.cs
@@ -19,16 +19,4 @@ public const string EnableUnsafeBinaryFormatterSerialization
     /// </summary>
     public const string LocalAppContext_DisableCaching
         = "TestSwitch.LocalAppContext.DisableCaching";
-
-    /// <summary>
-    ///  The switch that controls whether or not the <see cref="BinaryFormatter"/> is enabled in the Clipboard.
-    /// </summary>
-    public const string ClipboardDragDropEnableUnsafeBinaryFormatterSerializationSwitchName
-        = "Windows.ClipboardDragDrop.EnableUnsafeBinaryFormatterSerialization";
-
-    /// <summary>
-    ///  The switch that controls whether or not the System.Windows.Forms.BinaryFormat.Deserializer is enabled in the Clipboard.
-    /// </summary>
-    public const string ClipboardDragDropEnableNrbfSerializationSwitchName
-        = "Windows.ClipboardDragDrop.EnableNrbfSerialization";
 }
diff --git a/...em.Windows.Forms.Primitives/src/System/LocalAppContextSwitches/LocalAppContextSwitches.cs b/...em.Windows.Forms.Primitives/src/System/LocalAppContextSwitches/LocalAppContextSwitches.cs
@@ -96,58 +96,62 @@ private static bool GetSwitchValue(string switchName, ref int cachedSwitchValue)
         {
             cachedSwitchValue = isSwitchEnabled ? 1 /*true*/ : -1 /*false*/;
         }
+        else if (!hasSwitch)
+        {
+            AppContext.SetSwitch(switchName, isSwitchEnabled);
+        }
 
         return isSwitchEnabled;
+    }
 
-        static bool GetSwitchDefaultValue(string switchName)
+    private static bool GetSwitchDefaultValue(string switchName)
+    {
+        if (TargetFrameworkName is not { } framework)
         {
-            if (TargetFrameworkName is not { } framework)
-            {
-                return false;
-            }
+            return false;
+        }
 
-            if (switchName == NoClientNotificationsSwitchName)
-            {
-                return false;
-            }
+        if (switchName == NoClientNotificationsSwitchName)
+        {
+            return false;
+        }
 
-            if (switchName == TreeNodeCollectionAddRangeRespectsSortOrderSwitchName)
-            {
-                return true;
-            }
+        if (switchName == TreeNodeCollectionAddRangeRespectsSortOrderSwitchName)
+        {
+            return true;
+        }
 
-            if (switchName == ClipboardDragDropEnableUnsafeBinaryFormatterSerializationSwitchName)
+        if (switchName == ClipboardDragDropEnableUnsafeBinaryFormatterSerializationSwitchName)
+        {
+            return false;
+        }
+
+        if (switchName == ClipboardDragDropEnableNrbfSerializationSwitchName)
+        {
+            return true;
+        }
+
+        if (framework.Version.Major >= 8)
+        {
+            // Behavior changes added in .NET 8
+
+            if (switchName == ScaleTopLevelFormMinMaxSizeForDpiSwitchName)
             {
-                return false;
+                return true;
             }
 
-            if (switchName == ClipboardDragDropEnableNrbfSerializationSwitchName)
+            if (switchName == TrackBarModernRenderingSwitchName)
             {
                 return true;
             }
 
-            if (framework.Version.Major >= 8)
+            if (switchName == ServicePointManagerCheckCrlSwitchName)
             {
-                // Behavior changes added in .NET 8
-
-                if (switchName == ScaleTopLevelFormMinMaxSizeForDpiSwitchName)
-                {
-                    return true;
-                }
-
-                if (switchName == TrackBarModernRenderingSwitchName)
-                {
-                    return true;
-                }
-
-                if (switchName == ServicePointManagerCheckCrlSwitchName)
-                {
-                    return true;
-                }
+                return true;
             }
-
-            return false;
         }
+
+        return false;
     }
 
     /// <summary>
@@ -256,7 +260,6 @@ public static bool ClipboardDragDropEnableUnsafeBinaryFormatterSerialization
     public static bool ClipboardDragDropEnableNrbfSerialization
     {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        get =>
-            GetCachedSwitchValue(ClipboardDragDropEnableNrbfSerializationSwitchName, ref s_clipboardDragDropEnableNrbfSerialization);
+        get => GetCachedSwitchValue(ClipboardDragDropEnableNrbfSerializationSwitchName, ref s_clipboardDragDropEnableNrbfSerialization);
     }
 }
diff --git a/...inaryFormatterInClipboardDragDropScope.cs → ...inaryFormatterInClipboardDragDropScope.cs b/...inaryFormatterInClipboardDragDropScope.cs → ...inaryFormatterInClipboardDragDropScope.cs
@@ -5,12 +5,12 @@ namespace System;
 
 public readonly ref struct BinaryFormatterInClipboardDragDropScope
 {
-    private readonly AppContextSwitchScope _switchScope;
+    private readonly WinFormsAppContextSwitchScope _switchScope;
 
     public BinaryFormatterInClipboardDragDropScope(bool enable)
     {
         Monitor.Enter(typeof(BinaryFormatterInClipboardDragDropScope));
-        _switchScope = new(AppContextSwitchNames.ClipboardDragDropEnableUnsafeBinaryFormatterSerializationSwitchName, enable);
+        _switchScope = new(WinFormsAppContextSwitchNames.ClipboardDragDropEnableUnsafeBinaryFormatterSerializationSwitchName, enable);
     }
 
     public void Dispose()

diff --git a/...ipboardDragDropEnableNrbfSerialization.cs → ...ipboardDragDropEnableNrbfSerialization.cs b/...ipboardDragDropEnableNrbfSerialization.cs → ...ipboardDragDropEnableNrbfSerialization.cs
@@ -5,12 +5,12 @@ namespace System;
 
 public readonly ref struct NrbfSerializerInClipboardDragDropScope
 {
-    private readonly AppContextSwitchScope _switchScope;
+    private readonly WinFormsAppContextSwitchScope _switchScope;
 
     public NrbfSerializerInClipboardDragDropScope(bool enable)
     {
         Monitor.Enter(typeof(NrbfSerializerInClipboardDragDropScope));
-        _switchScope = new(AppContextSwitchNames.ClipboardDragDropEnableNrbfSerializationSwitchName, enable);
+        _switchScope = new(WinFormsAppContextSwitchNames.ClipboardDragDropEnableNrbfSerializationSwitchName, enable);
     }
 
     public void Dispose()

diff --git a/src/System.Windows.Forms/tests/TestUtilities/WinFormsAppContextSwitchNames.cs b/src/System.Windows.Forms/tests/TestUtilities/WinFormsAppContextSwitchNames.cs
@@ -1,6 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Runtime.Serialization.Formatters.Binary;
+
 namespace System;
 
 public static class WinFormsAppContextSwitchNames
@@ -50,4 +52,16 @@ public const string ServicePointManagerCheckCrl
     /// </summary>
     public const string TreeNodeCollectionAddRangeRespectsSortOrder
         = "System.Windows.Forms.ApplyParentFontToMenus";
+
+    /// <summary>
+    ///  The switch that controls whether or not the <see cref="BinaryFormatter"/> is enabled in the Clipboard.
+    /// </summary>
+    public const string ClipboardDragDropEnableUnsafeBinaryFormatterSerializationSwitchName
+        = "Windows.ClipboardDragDrop.EnableUnsafeBinaryFormatterSerialization";
+
+    /// <summary>
+    ///  The switch that controls whether or not the System.Windows.Forms.BinaryFormat.Deserializer is enabled in the Clipboard.
+    /// </summary>
+    public const string ClipboardDragDropEnableNrbfSerializationSwitchName
+        = "Windows.ClipboardDragDrop.EnableNrbfSerialization";
 }
diff --git a/src/System.Windows.Forms/tests/TestUtilities/WinFormsAppContextSwitchScope.cs b/src/System.Windows.Forms/tests/TestUtilities/WinFormsAppContextSwitchScope.cs
@@ -0,0 +1,54 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Windows.Forms.Primitives;
+
+namespace System;
+
+/// <summary>
+///  Scope for temporarily setting an <see cref="AppContext"/> switch. Use in a <see langword="using"/> statement.
+/// </summary>
+/// <remarks>
+///  <para>
+///   It is recommended to create wrappers for this struct for both simplicity and to allow adding synchronization.
+///   See <see cref="BinaryFormatterScope"/> for an example of doing this.
+///  </para>
+/// </remarks>
+public readonly ref struct WinFormsAppContextSwitchScope
+{
+    private readonly string _switchName;
+    private readonly bool _originalState;
+
+    public WinFormsAppContextSwitchScope(string switchName, bool enable)
+    {
+        if (!AppContext.TryGetSwitch(AppContextSwitchNames.LocalAppContext_DisableCaching, out bool isEnabled)
+            || !isEnabled)
+        {
+            // It doesn't make sense to try messing with AppContext switches if they are going to be cached.
+            throw new InvalidOperationException("LocalAppContext switch caching is not disabled.");
+        }
+
+        if (!AppContext.TryGetSwitch(switchName, out _originalState))
+        {
+            var getDefaultValue = typeof(LocalAppContextSwitches).TestAccessor().CreateDelegate<Func<string, bool>>("GetSwitchDefaultValue");
+            _originalState = getDefaultValue(switchName);
+        }
+
+        AppContext.SetSwitch(switchName, enable);
+        if (!AppContext.TryGetSwitch(switchName, out isEnabled) || isEnabled != enable)
+        {
+            throw new InvalidOperationException($"Could not set {switchName} to {enable}.");
+        }
+
+        _switchName = switchName;
+    }
+
+    public void Dispose()
+    {
+        AppContext.SetSwitch(_switchName, _originalState);
+        if (!AppContext.TryGetSwitch(_switchName, out bool isEnabled) || isEnabled != _originalState)
+        {
+            throw new InvalidOperationException($"Could not reset {_switchName} to {_originalState}.");
+        }
+    }
+}
diff --git a/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ClipboardTests.cs b/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ClipboardTests.cs
@@ -18,7 +18,7 @@ namespace System.Windows.Forms.Tests;
 // Note: each registered Clipboard format is an OS singleton
 // and we should not run this test at the same time as other tests using the same format.
 [Collection("Sequential")]
-[UISettings(MaxAttempts = 3)] // Try up to 3 times before failing.
+// [UISettings(MaxAttempts = 3)] // Try up to 3 times before failing.
 public class ClipboardTests
 {
 #pragma warning disable WFDEV005 // Type or member is obsolete
@@ -659,6 +659,8 @@ public void Clipboard_BinaryFormatter_AppContextSwitch()
         {
             LocalAppContextSwitches.ClipboardDragDropEnableUnsafeBinaryFormatterSerialization.Should().BeFalse();
         }
+
+        LocalAppContextSwitches.ClipboardDragDropEnableUnsafeBinaryFormatterSerialization.Should().BeFalse();
     }
 
     [WinFormsFact]
@@ -678,6 +680,8 @@ public void Clipboard_NrbfSerializer_AppContextSwitch()
         {
             LocalAppContextSwitches.ClipboardDragDropEnableNrbfSerialization.Should().BeTrue();
         }
+
+        LocalAppContextSwitches.ClipboardDragDropEnableNrbfSerialization.Should().BeTrue();
     }
 
     [WinFormsFact]