HangDump should trigger even after test session finish

[Youssef1313]

Fixes #7314

[Evangelink]

It'd be great to create a new acceptance test where we spawn a thread or something and show that now hang dump triggers

[Copilot]

Pull request overview

This PR fixes a hang issue (#7314) where dotnet test hangs after completing tests when running multiple test projects in a solution with MSTest SDK 4.0.2. The fix removes the session end coordination mechanism between the test host process and the parent process.

Changes:

• Removed SessionEndSerializer and its associated request/response handling
• Removed session end signaling from HangDumpActivityIndicator.OnTestSessionFinishingAsync
• Simplified disposal logic by removing conditional disposal based on _sessionEndCalled flag

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
SessionEndSerializer.cs	Entire file deleted - removes the session end serializer that was used for coordination between test host and parent process
HangDumpProcessLifetimeHandler.cs	Removed session end request handling and conditional activity timer disposal logic
HangDumpActivityIndicator.cs	Removed session end signaling in OnTestSessionFinishingAsync and simplified disposal by removing conditional cleanup logic

Comments suppressed due to low confidence (1)

src/Platform/Microsoft.Testing.Extensions.HangDump/HangDumpActivityIndicator.cs:196

• The _singleConnectionNamedPipeServer resource is created in OnTestSessionStartingAsync (line 96) but is never disposed in Dispose. This creates a resource leak that could cause hangs or prevent proper cleanup. The server should be disposed to ensure the named pipe resources are properly released.

    public void Dispose()
        => _namedPipeClient?.Dispose();

[Youssef1313]

It'd be great to create a new acceptance test where we spawn a thread or something and show that now hang dump triggers

@copilot Please add this test.

[Copilot]

@Youssef1313 I've opened a new pull request, #7429, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.