Allow NodeProviderOutOfProcTaskHost to manage multiple nodes instead of one per arch

[surayya-MS]

Fixes #12552

Context

Currently, for multithreaded node we cannot force all tasks to run in task hosts by setting MSBUILDFORCEALLTASKSOUTOFPROC=1. It crashes. The problem is that NodeProviderOutOfProcTaskHost is one per process, and manages up to 4 nodes for specific architecture.

Changes Made

1. Propagated nodeId if the in-proc nodes (only when multi-threaded mode is on) into NodeProviderOutOfProcTaskHost
2. Used nodeId with the combination of (int)HanshakeOptions (is originally used as key for _nodeContexts), to generate a unique id for task host node

Testing

Manually tested by building this project that references other projects with Message tasks. Modified Message task to show the process id it is running on.
msbuild.exe .\MainProject.proj - m with combination of with/without -mt switch and with/without setting MSBUILDFORCEALLTASKSOUTOFPROC.

Notes

[Copilot]

Pull Request Overview

This PR modifies the NodeProviderOutOfProcTaskHost to manage multiple task host nodes instead of being limited to one node per architecture. The change enables better support for multi-threaded builds where multiple in-process nodes need to distinguish their task hosts.

• Introduces a new task host node ID generation system that combines scheduled node ID with architecture/runtime information
• Updates the NodeProviderOutOfProcTaskHost to use ConcurrentDictionary and support unlimited nodes
• Threads the scheduled node ID through the task execution pipeline from BuildRequest to TaskHostTask

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
TaskHostTask.cs	Adds scheduledNodeId parameter and GenerateTaskHostNodeId method for unique task host identification
AssemblyTaskFactory.cs	Passes scheduledNodeId parameter when creating TaskHostTask instances
TaskExecutionHost.cs	Threads scheduledNodeId through task initialization and instantiation
BuildRequest.cs	Adds ScheduledNodeId property to track which node a request is assigned to
InProcNode.cs	Sets ScheduledNodeId on build requests and stores node ID
TaskBuilder.cs	Passes scheduledNodeId from build request to task execution host
NodeProviderOutOfProcTaskHost.cs	Replaces HandshakeOptions-based mapping with concurrent node ID mapping
NodeProviderInProc.cs	Passes nodeId when creating InProcNode instances
NodeManager.cs	Extracts multi-threaded mode check to local variable
TaskExecutionHost_Tests.cs	Updates test calls to include scheduledNodeId parameter
AssemblyTaskFactory_Tests.cs	Updates test calls to include scheduledNodeId parameter

[JanProvaznik]

I think this is well executed change, please address/discuss comments. Then lgtm.

[AR-May]

Looks overall good for me. I wonder about 2 things:

1. Can we hide using the task node id instead of handshake casted to int behind a change wave
2. Can we make a test that would catch the initial bug - that task host for different nodes should be different?

[surayya-MS]

Can we hide using the task node id instead of handshake casted to int behind a change wave

@AR-May I can make it so that task host node id is only used for multithreaded mode.

[surayya-MS]

2. Can we make a test that would catch the initial bug - that task host for different nodes should be different?

@AR-May I'll try to do that in the follow-up PR.
For now, the testing was manual. Tested on combination of - with/without -mt and with/without setting MSBUILDFORCEALLTASKSOUTOFPROC. With MSBUILDFORCEALLTASKSOUTOFPROC=1 making sure that process ids are the same for the same project

[AR-May]

2. Can we make a test that would catch the initial bug - that task host for different nodes should be different?

@AR-May I'll try to do that in the follow-up PR. For now, the testing was manual. Tested on combination of - with/without -mt and with/without setting MSBUILDFORCEALLTASKSOUTOFPROC. With MSBUILDFORCEALLTASKSOUTOFPROC=1 making sure that process ids are the same for the same project

Ok, works for me!