Disable default and ambient attribute at runtime with a feature switch (

dotnet#100416) * Disable default and ambient attribute at runtime with a feature switch * throwing at the getter at runtime
BruceForstall · Apr 5, 2024 · 92afc71 · 92afc71
1 parent 3515c7a
commit 92afc71
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Showing 4 changed files with 63 additions and 14 deletions.
diff --git a/src/libraries/System.ComponentModel.TypeConverter/src/Resources/Strings.resx b/src/libraries/System.ComponentModel.TypeConverter/src/Resources/Strings.resx
@@ -106,6 +106,9 @@
   <data name="NullableConverterBadCtorArg" xml:space="preserve">
     <value>The specified type is not a nullable type.</value>
   </data>
+  <data name="RuntimeInstanceNotAllowed" xml:space="preserve">
+    <value>Runtime instantiation of this attribute is not allowed.</value>
+  </data>
   <data name="Text" xml:space="preserve">
     <value>(Text)</value>
   </data>

diff --git a/...es/System.ComponentModel.TypeConverter/src/System/ComponentModel/AmbientValueAttribute.cs b/...es/System.ComponentModel.TypeConverter/src/System/ComponentModel/AmbientValueAttribute.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.ComponentModel.Design;
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 
 namespace System.ComponentModel
@@ -12,6 +14,11 @@ namespace System.ComponentModel
     [AttributeUsage(AttributeTargets.All)]
     public sealed class AmbientValueAttribute : Attribute
     {
+        /// <summary>
+        /// This is the default value.
+        /// </summary>
+        private object? _value;
+
         /// <summary>
         /// Initializes a new instance of the <see cref='System.ComponentModel.AmbientValueAttribute'/> class, converting the
         /// specified value to the specified type, and using the U.S. English culture as the
@@ -22,9 +29,15 @@ public AmbientValueAttribute([DynamicallyAccessedMembers(DynamicallyAccessedMemb
         {
             // The try/catch here is because attributes should never throw exceptions. We would fail to
             // load an otherwise normal class.
+
+            if (!IDesignerHost.IsSupported)
+            {
+                return;
+            }
+
             try
             {
-                Value = TypeDescriptor.GetConverter(type).ConvertFromInvariantString(value);
+                _value = TypeDescriptor.GetConverter(type).ConvertFromInvariantString(value);
             }
             catch
             {
@@ -37,7 +50,7 @@ public AmbientValueAttribute([DynamicallyAccessedMembers(DynamicallyAccessedMemb
         /// </summary>
         public AmbientValueAttribute(char value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -46,7 +59,7 @@ public AmbientValueAttribute(char value)
         /// </summary>
         public AmbientValueAttribute(byte value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -55,7 +68,7 @@ public AmbientValueAttribute(byte value)
         /// </summary>
         public AmbientValueAttribute(short value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -64,7 +77,7 @@ public AmbientValueAttribute(short value)
         /// </summary>
         public AmbientValueAttribute(int value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -73,7 +86,7 @@ public AmbientValueAttribute(int value)
         /// </summary>
         public AmbientValueAttribute(long value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -82,7 +95,7 @@ public AmbientValueAttribute(long value)
         /// </summary>
         public AmbientValueAttribute(float value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -91,7 +104,7 @@ public AmbientValueAttribute(float value)
         /// </summary>
         public AmbientValueAttribute(double value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -100,15 +113,15 @@ public AmbientValueAttribute(double value)
         /// </summary>
         public AmbientValueAttribute(bool value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
         /// Initializes a new instance of the <see cref='System.ComponentModel.AmbientValueAttribute'/> class using a <see cref='string'/>.
         /// </summary>
         public AmbientValueAttribute(string? value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
@@ -117,13 +130,22 @@ public AmbientValueAttribute(string? value)
         /// </summary>
         public AmbientValueAttribute(object? value)
         {
-            Value = value;
+            _value = value;
         }
 
         /// <summary>
         /// Gets the ambient value of the property this attribute is bound to.
         /// </summary>
-        public object? Value { get; }
+        public object? Value {
+            get
+            {
+                if (!IDesignerHost.IsSupported)
+                {
+                    throw new ArgumentException(SR.RuntimeInstanceNotAllowed);
+                }
+                return _value;
+            }
+        }
 
         public override bool Equals([NotNullWhen(true)] object? obj)
         {

diff --git a/src/libraries/System.Private.CoreLib/src/Resources/Strings.resx b/src/libraries/System.Private.CoreLib/src/Resources/Strings.resx
@@ -3359,6 +3359,9 @@
   <data name="RFLCT_Targ_StatMethReqTarg" xml:space="preserve">
     <value>Non-static method requires a target.</value>
   </data>
+  <data name="RuntimeInstanceNotAllowed" xml:space="preserve">
+    <value>Runtime instantiation of this attribute is not allowed.</value>
+  </data>
   <data name="RuntimeWrappedException" xml:space="preserve">
     <value>An object that does not derive from System.Exception has been wrapped in a RuntimeWrappedException.</value>
   </data>
@@ -4313,4 +4316,4 @@
   <data name="WasmThreads_BlockingWaitNotSupportedOnJSInterop" xml:space="preserve">
     <value>Blocking wait is not supported on the JS interop threads.</value>
   </data>
-</root>
+</root>
diff --git a/src/libraries/System.Private.CoreLib/src/System/ComponentModel/DefaultValueAttribute.cs b/src/libraries/System.Private.CoreLib/src/System/ComponentModel/DefaultValueAttribute.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Reflection;
@@ -22,6 +23,9 @@ public class DefaultValueAttribute : Attribute
         // Delegate ad hoc created 'TypeDescriptor.ConvertFromInvariantString' reflection object cache
         private static object? s_convertFromInvariantString;
 
+        [FeatureSwitchDefinition("System.ComponentModel.DefaultValueAttribute.IsSupported")]
+        internal static bool IsSupported => AppContext.TryGetSwitch("System.ComponentModel.DefaultValueAttribute.IsSupported", out bool isSupported) ? isSupported : true;
+
         /// <summary>
         /// Initializes a new instance of the <see cref='DefaultValueAttribute'/>
         /// class, converting the specified value to the specified type, and using the U.S. English
@@ -35,6 +39,12 @@ public DefaultValueAttribute(
             // The null check and try/catch here are because attributes should never throw exceptions.
             // We would fail to load an otherwise normal class.
 
+            if (!IsSupported)
+            {
+                Debug.Assert(!IsSupported, "Runtime instantiation of this attribute is not allowed.");
+                return;
+            }
+
             if (type == null)
             {
                 return;
@@ -229,7 +239,18 @@ public DefaultValueAttribute(ulong value)
         /// <summary>
         /// Gets the default value of the property this attribute is bound to.
         /// </summary>
-        public virtual object? Value => _value;
+        public virtual object? Value
+        {
+            get
+            {
+                if (!IsSupported)
+                {
+                    throw new ArgumentException(SR.RuntimeInstanceNotAllowed);
+                }
+                return _value;
+            }
+        }
+
 
         public override bool Equals([NotNullWhen(true)] object? obj)
         {