fix: preserve PATHEXT for Windows cached tasks (#366)

Fixes #365.

Preserves PATHEXT in the default Windows environment passthrough so
PowerShell package shims can resolve node.exe during cached task
execution.

<details>
<summary>Why PATHEXT is required</summary>

In the issue repro, `marker-cli` is exposed through a pnpm-generated
`node_modules/.bin/marker-cli.ps1` shim. On Windows, that shim sets
`$exe = ".exe"` and then falls back to invoking Node by name:

```powershell
& "node$exe" "$basedir/../marker-cli/bin/marker-cli.mjs" $args
```

So the actual command is `& "node.exe" ...`.

When `PATHEXT` is missing from the sanitized cached-task environment,
PowerShell can still locate `node.exe` with `Get-Command node.exe`, but
native invocation by name does not run correctly: `& "node.exe"
--version` produces no output, `$LASTEXITCODE` is unset, and the repro
marker file is not created. Restoring `PATHEXT` with `.EXE` makes the
same shim execute normally and create the marker.

This is why preserving `PATHEXT` fixes the cached PowerShell shim path
without changing fspy or the shim rewrite itself.
</details>

Verified with the issue repro on Windows, `cargo fmt --check`, `cargo
build -p vite_task_bin`, and `cargo test -p vite_task_plan --test
plan_snapshots -- windows_cmd_shim_rewrite`.

---------

Co-authored-by: SegaraRai <29276700+SegaraRai@users.noreply.github.com>
Co-authored-by: branchseer <dk4rest@gmail.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 3 people

CHANGELOG.md

@@ -1,5 +1,6 @@
 # Changelog
 
+- **Fixed** Windows cached tasks can now run package shims rewritten through PowerShell; default env passthrough now preserves `PATHEXT` ([#366](https://github.com/voidzero-dev/vite-task/pull/366))
 - **Added** Platform support for targets without `input` auto-inference (e.g. Android). Tasks still run; those relying on auto-inference run uncached, with the summary noting that `input` must be configured manually to enable caching ([#352](https://github.com/voidzero-dev/vite-task/pull/352))
 - **Fixed** `vp run` no longer aborts with `failed to prepare the command for injection: Invalid argument` when the user environment already has `LD_PRELOAD` (Linux) or `DYLD_INSERT_LIBRARIES` (macOS) set. The tracer shim is now appended to any existing value and placed last, so user preloads keep their symbol-interposition precedence ([#340](https://github.com/voidzero-dev/vite-task/issues/340))
 - **Changed** Arguments passed after a task name (e.g. `vp run test some-filter`) are now forwarded only to that task. Tasks pulled in via `dependsOn` no longer receive them ([#324](https://github.com/voidzero-dev/vite-task/issues/324))

crates/vite_task_bin/tests/e2e_snapshots/fixtures/windows_powershell_shim_pathext/.gitignore

@@ -0,0 +1,3 @@
+# This fixture intentionally tracks package-shim files under node_modules/.bin.
+!node_modules
+!node_modules/**

crates/vite_task_bin/tests/e2e_snapshots/fixtures/windows_powershell_shim_pathext/node_modules/.bin/probe-cli.cmd

@@ -0,0 +1,3 @@
+{
+  "name": "windows-powershell-shim-pathext"
+}

crates/vite_task_bin/tests/e2e_snapshots/fixtures/windows_powershell_shim_pathext/node_modules/.bin/probe-cli.ps1

@@ -0,0 +1,23 @@
+[[e2e]]
+name = "powershell_package_shim_keeps_pathext"
+platform = "windows"
+comment = """
+Cached Windows tasks run with a sanitized environment, and pnpm-style package
+`.cmd` shims in `node_modules/.bin` are rewritten at plan time to invoke their
+`.ps1` sibling via `powershell.exe -File`. PowerShell needs `PATHEXT` in that
+environment to launch native executables — even when the executable name is
+written out with a `.exe` extension — so `PATHEXT` must be preserved in the
+default untracked env passthrough.
+"""
+steps = [
+  { argv = [
+    "vt",
+    "run",
+    "probe",
+  ], comment = "rewritten to `powershell.exe -File probe-cli.ps1`; the shim launches `vtt.exe write-file` to write `marker.txt`" },
+  { argv = [
+    "vtt",
+    "print-file",
+    "marker.txt",
+  ], comment = "marker is present only if the shim's `vtt.exe` launch succeeded" },
+]

crates/vite_task_bin/tests/e2e_snapshots/fixtures/windows_powershell_shim_pathext/package.json

@@ -0,0 +1,25 @@
+# powershell_package_shim_keeps_pathext
+
+Cached Windows tasks run with a sanitized environment, and pnpm-style package
+`.cmd` shims in `node_modules/.bin` are rewritten at plan time to invoke their
+`.ps1` sibling via `powershell.exe -File`. PowerShell needs `PATHEXT` in that
+environment to launch native executables — even when the executable name is
+written out with a `.exe` extension — so `PATHEXT` must be preserved in the
+default untracked env passthrough.
+
+## `vt run probe`
+
+rewritten to `powershell.exe -File probe-cli.ps1`; the shim launches `vtt.exe write-file` to write `marker.txt`
+
+```
+$ probe-cli
+shim-ran
+```
+
+## `vtt print-file marker.txt`
+
+marker is present only if the shim's `vtt.exe` launch succeeded
+
+```
+shim-ran
+```

crates/vite_task_bin/tests/e2e_snapshots/fixtures/windows_powershell_shim_pathext/snapshots.toml

@@ -0,0 +1,10 @@
+{
+  "cache": true,
+  "tasks": {
+    "probe": {
+      "command": "probe-cli",
+      "cache": true,
+      "input": []
+    }
+  }
+}

crates/vite_task_bin/tests/e2e_snapshots/fixtures/windows_powershell_shim_pathext/snapshots/powershell_package_shim_keeps_pathext.md

@@ -382,6 +382,7 @@ pub const DEFAULT_UNTRACKED_ENV: &[&str] = &[
     "HOMEDRIVE",
     "HOMEPATH",
     "WINDIR",
+    "PATHEXT",
     "ProgramFiles",
     "ProgramFiles[(]x86[)]", // Parens escaped for glob syntax (Turborepo uses literal `ProgramFiles(x86)`)
     // IDE specific (exact matches)