Add DebuggerDisableUserUnhandledExceptionsAttribute

src/coreclr/System.Private.CoreLib/src/System/Diagnostics/Debugger.cs

@@ -91,5 +91,16 @@ public static extern bool IsAttached
         // report the notification depending on its settings.
         [MethodImpl(MethodImplOptions.InternalCall)]
         private static extern void CustomNotification(ICustomDebuggerNotification data);
+
+        /// <summary>
+        /// If a .NET Debugger is attached with break on user-unhandled exception enabled and a method attributed with
+        /// DebuggerDisableUserUnhandledExceptionsAttribute calls this method, the debugger will break with the
+        /// <paramref name="exception"/> details.
+        /// </summary>
+        /// <param name="exception">The user-unhandled exception.</param>
+        [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
+        public static void BreakForUserUnhandledException(Exception exception)
+        {
+        }
     }
 }

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -293,6 +293,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Debug.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\DebuggableAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\DebuggerBrowsableAttribute.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\DebuggerDisableUserUnhandledExceptionsAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\DebuggerDisplayAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\DebuggerHiddenAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\DebuggerNonUserCodeAttribute.cs" />
@@ -2800,4 +2801,4 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\IUnaryPlusOperators.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\IUnsignedNumber.cs" />
   </ItemGroup>
-</Project>
+</Project>

src/libraries/System.Private.CoreLib/src/System/Diagnostics/DebuggerDisableUserUnhandledExceptionsAttribute.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Diagnostics
+{
+    /// <summary>
+    /// If a .NET Debugger is attached which supports the Debugger.BreakForUserUnhandledException(Exception) API,
+    /// this attribute will prevent the debugger from breaking on user-unhandled exceptions when the
+    /// exception is caught by a method with this attribute, unless BreakForUserUnhandledException is called.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method)]
+    public sealed class DebuggerDisableUserUnhandledExceptionsAttribute : Attribute
+    {
+    }
+}

src/libraries/System.Runtime/ref/System.Runtime.cs

@@ -8666,6 +8666,7 @@ public static partial class Debugger
         public static readonly string? DefaultCategory;
         public static bool IsAttached { get { throw null; } }
         public static void Break() { }
+        public static void BreakForUserUnhandledException(Exception exception) { }
         public static bool IsLogging() { throw null; }
         public static bool Launch() { throw null; }
         public static void Log(int level, string? category, string? message) { }
@@ -8683,6 +8684,11 @@ public enum DebuggerBrowsableState
         Collapsed = 2,
         RootHidden = 3,
     }
+    [AttributeUsage(AttributeTargets.Method)]
+    public sealed class DebuggerDisableUserUnhandledExceptionsAttribute : Attribute
+    {
+        public DebuggerDisableUserUnhandledExceptionsAttribute() { }
+    }
     [System.AttributeUsageAttribute(System.AttributeTargets.Assembly | System.AttributeTargets.Class | System.AttributeTargets.Delegate | System.AttributeTargets.Enum | System.AttributeTargets.Field | System.AttributeTargets.Property | System.AttributeTargets.Struct, AllowMultiple=true)]
     public sealed partial class DebuggerDisplayAttribute : System.Attribute
     {

src/mono/System.Private.CoreLib/src/System/Diagnostics/Debugger.cs

@@ -41,5 +41,9 @@ public static void Log(int level, string? category, string? message)
         public static void NotifyOfCrossThreadDependency()
         {
         }
+
+        public static void BreakForUserUnhandledException(Exception exception)
+        {
+        }
     }
 }