Migrating MSBuild Tasks to Multithreaded API

MSBuild's multithreaded execution model requires tasks to avoid global process state (working directory, environment variables). Thread-safe tasks declare this capability via MSBuildMultiThreadableTask and use TaskEnvironment from IMultiThreadableTask for safe alternatives.

Migration Steps

Step 1: Update Task Class Declaration

a. Ensure the task implementing class is decorated with the MSBuildMultiThreadableTask attribute. b. Implement IMultiThreadableTask only if the task needs TaskEnvironment APIs (path absolutization, env vars, process start). If the task has no file/environment operations (e.g., a stub class), the attribute alone is sufficient.

[MSBuildMultiThreadableTask]
public class MyTask : Task, IMultiThreadableTask
{
    public TaskEnvironment TaskEnvironment { get; set; } = TaskEnvironment.Fallback;
    ...
}