MSBuildMultiThreadableTaskAttribute.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#nullable enable

using System;

namespace Microsoft.Build.Framework
{
    /// <summary>
    /// Attribute that marks a task class as thread-safe for multithreaded execution.
    /// </summary>
    /// <remarks>
    /// Task classes marked with this attribute indicate they can be safely executed in parallel 
    /// in the same process with other tasks.
    /// 
    /// Tasks using this attribute must satisfy strict requirements:
    /// - Must not modify global process state (environment variables, working directory, etc.)
    /// - Must not depend on global process state, including relative path resolution
    /// - Must safely handle registered task objects shared across thread nodes
    /// 
    /// MSBuild detects this attribute by its namespace and name only, ignoring the defining assembly.
    /// This allows customers to define the attribute in their own assemblies alongside their tasks.
    /// 
    /// When defining polyfilled versions of this attribute in customer assemblies,
    /// they must also specify Inherited = false to ensure proper non-inheritable semantics.
    /// </remarks>
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
    public class MSBuildMultiThreadableTaskAttribute : Attribute
    {
        /// <summary>
        /// Initializes a new instance of the MSBuildMultiThreadableTaskAttribute class.
        /// </summary>
        public MSBuildMultiThreadableTaskAttribute()
        {
        }
    }
}