Windows cached task hangs after first compound command when stdio pipe remains open

[kazupon]

Summary

On Windows, a cached vp run task can hang after the first command in a compound script has completed, before the next && command starts.

This was reproduced with a script shape similar to:

{
  "scripts": {
    "test": "cargo test -p ox_mf2_parser --all-targets --color always && vp test"
  }
}

Reproduction

Repro repo: https://github.com/kazupon/vite-task-windows-issue-1
(cause repo: https://github.com/intlify/intlify)

In GitHub Actions, the normal cached Windows run hangs, while the Windows --no-cache control run completes successfully.

Observed behavior

The cached run prints and completes the cargo test output, but never prints or starts the following $ vp test command.

Process snapshots show only the vpr / vp / node runner process tree remaining. No cargo, rustc, or vitest process remains. At workflow cleanup, GitHub Actions reports an orphaned vctip process.

Expected behavior

After the direct child process for the first command exits, the runner should observe completion and continue to the next && command, even if a descendant temporarily keeps stdout/stderr handles open.

Suspected cause

The cached execution path drains piped stdout/stderr before awaiting the direct child process. On Windows, if a descendant keeps an inherited pipe handle open, EOF never arrives, so the runner never reaches child wait or Windows Job Object cleanup.

[kazupon]

Opened a draft PR with the proposed fix: #486.

Summary of the fix:

• run_child now polls piped stdout/stderr drain and the direct child wait future concurrently, so pipe EOF wait alone cannot block direct child exit observation.
• stop_accepting.signal() now runs immediately after the direct child wait resolves, before waiting for any remaining stdio drain.
• Added a Windows-only E2E regression fixture, windows_cached_pipe_handle_hang, where a descendant keeps inherited stdout/stderr handles open and the task must still proceed to the next && command.

Local non-Windows checks pass, including cargo fmt --all --check, cargo check -p vite_task --all-features, cargo clippy -p vite_task --all-features -- --deny warnings, targeted cached/concurrent/cancellation E2E tests, and cargo test -p vite_task --all-features.

Windows PR CI is currently blocked on GitHub Actions approval for the fork PR, so the Windows fixture and external repro confirmation are still pending.