fix: close child stdin so pnpm PowerShell shim doesn't deadlock on Windows

[fengmk2]

Summary

@actions/exec leaves child stdin open by default. pnpm's pnpm.ps1 shim takes the $MyInvocation.ExpectingInput branch when stdin is a pipe and drains $input until EOF before invoking node. With stdin inherited from the runner and never closed, that drain blocks forever — pwsh.exe running pnpm.ps1 stays alive but no node child is ever spawned, and the job times out silently.

Fix: pass input: Buffer.alloc(0) to exec so the child sees immediate EOF on stdin and the shim falls through to spawn node.

Repro & evidence

Failing run before fix: https://github.com/voidzero-dev/setup-vp/actions/runs/24870325083/job/74809705560 — test (windows-latest, alpha) hangs 5+ minutes after Setting up VITE+... then is canceled. windows-latest, latest finishes in ~13s on the same install path.

A short-lived diagnostic commit (replaced by this fix) added a heartbeat that snapshotted descendants of the pwsh PID every 30s. It showed:

pid=6264 cmd.exe   :: cmd /c "set CI=true && vp.exe install"
pid=5828 vp.exe    :: vp.exe install
pid=6656 pwsh.exe  :: pwsh -File ...\pnpm\10.33.0\pnpm\bin\pnpm.ps1 install

Same tree across three consecutive heartbeats, never spawning a node child — the pnpm shim is alive but blocked on draining stdin before it ever invokes node.

Test plan

• test (windows-latest, alpha) runs to completion on this PR (previously hung).
• Other matrix jobs still pass — empty stdin is safe on bash too (the inner curl | bash pipe is independent of the outer bash's stdin).
• Local vp test passes (115/115).

[Copilot]

Pull request overview

This PR modifies the GitHub Action’s Vite+ installer invocation to avoid a Windows-specific hang by explicitly closing stdin for the child process.

Changes:

• Pass input: Buffer.alloc(0) to @actions/exec so the spawned pwsh (and currently also bash) process sees EOF on stdin.
• Regenerate dist/index.mjs to include the compiled change.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/install-viteplus.ts	Adds exec options to close stdin (empty input) during install to prevent PowerShell/pnpm shim deadlock.
dist/index.mjs	Updates the bundled output to reflect the new exec option.

Comments suppressed due to low confidence (1)

src/install-viteplus.ts:68

• input: Buffer.alloc(0) is currently applied to both the Windows pwsh path and the non-Windows bash path, but the rationale in the comment is Windows/pnpm-specific. Consider scoping the stdin-closing behavior to process.platform === "win32" (or adding a short note explaining why it’s safe/desirable on non-Windows too) to avoid unnecessarily changing install.sh execution semantics.

  // Close child stdin (empty input) so pnpm's PowerShell shim doesn't deadlock.
  // The shim's `$MyInvocation.ExpectingInput` branch drains $input until EOF
  // before invoking node; if we leave stdin open, that drain never returns and
  // pnpm install hangs forever — observed on Windows alpha runs with
  // vite-plus@0.1.21-alpha.2 (pwsh.exe -File pnpm.ps1 alive, no node child).
  const options = { env, ignoreReturnCode: true, input: Buffer.alloc(0) };
  if (process.platform === "win32") {
    return exec(
      "pwsh",
      ["-Command", `& ([scriptblock]::Create((irm ${INSTALL_URL_PS1})))`],
      options,
    );
  }
  return exec("bash", ["-c", `curl -fsSL ${INSTALL_URL_SH} | bash`], options);

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