fix: drop patchPnpmEnv so standalone+self-update works on Windows (#258)

`patchPnpmEnv` prepended `dest/node_modules/.bin` to PATH before
spawning `pnpm install` / `pnpm store prune`. On Windows in standalone
mode, `.bin/pnpm.cmd` is an npm-created shim that always points at the
BOOTSTRAP pnpm (currently 11.0.4) — the binary npm linked when it
installed `@pnpm/exe` into `node_modules`. The self-updated pnpm
written by `pnpm self-update` lives at `$PNPM_HOME/bin`, which is
separately added to PATH via `addPath()` in install-pnpm.

When the user requested a pnpm version different from the bootstrap
under `standalone: true` on Windows, patchPnpmEnv's `.bin` entry
shadowed the self-updated `$PNPM_HOME/bin` and the action's internal
`pnpm install` ran on the bootstrap. On a pnpm 11.0.x bootstrap this
broke any 11.1+ install flag (e.g. `--no-runtime`), reporting:

    ERROR  Unknown option: 'runtime'

POSIX standalone got lucky because `.bin` and `$PNPM_HOME` resolve to
the same directory there. Non-standalone never tripped on this since
the `.bin/pnpm` symlink for a regular `pnpm` package keeps working
across self-updates.

Removed `patchPnpmEnv` and the now-empty `src/utils/` module.
`spawnSync` now inherits `process.env`, whose PATH is already
correctly fronted by `$PNPM_HOME/bin` and `$PNPM_HOME` via the
`addPath` calls in install-pnpm.

Added `standalone_windows_self_update` to test.yaml as a regression
guard: standalone on Windows + target 11.1.0 + `run_install` with
`--no-runtime`. With the previous code, the install would have run
under the bootstrap (11.0.4) and errored on the unknown flag.

Originally found while building pnpm/setup (the new combined
pnpm + runtime action).

src/pnpm-install/index.ts

@@ -1,11 +1,8 @@
 import { setFailed, startGroup, endGroup } from '@actions/core'
 import { spawnSync } from 'child_process'
 import { Inputs } from '../inputs'
-import { patchPnpmEnv } from '../utils'
 
 export function runPnpmInstall(inputs: Inputs) {
-  const env = patchPnpmEnv(inputs)
-
   for (const options of inputs.runInstall) {
     const args = ['install']
     if (options.recursive) args.unshift('recursive')
@@ -14,11 +11,16 @@ export function runPnpmInstall(inputs: Inputs) {
     const cmdStr = ['pnpm', ...args].join(' ')
     startGroup(`Running ${cmdStr}...`)
 
+    // spawnSync inherits process.env, which already has $PNPM_HOME/bin and
+    // $PNPM_HOME prepended via addPath() in install-pnpm. Do NOT pass a
+    // hand-patched env that adds node_modules/.bin to the front — on
+    // Windows standalone, .bin/pnpm.cmd is an npm shim pointing at the
+    // BOOTSTRAP pnpm, which would shadow the self-updated one and break
+    // newer-pnpm-only behavior.
     const { error, status } = spawnSync('pnpm', args, {
       stdio: 'inherit',
       cwd: options.cwd,
       shell: true,
-      env,
     })
 
     endGroup()

src/pnpm-store-prune/index.ts

@@ -1,7 +1,6 @@
 import { warning, startGroup, endGroup } from '@actions/core'
 import { spawnSync } from 'child_process'
 import { Inputs } from '../inputs'
-import { patchPnpmEnv } from '../utils'
 
 export function pruneStore(inputs: Inputs) {
   if (inputs.runInstall.length === 0) {
@@ -10,10 +9,11 @@ export function pruneStore(inputs: Inputs) {
   }
 
   startGroup('Running pnpm store prune...')
+  // spawnSync inherits process.env (which has the right PATH from addPath
+  // in install-pnpm). See pnpm-install/index.ts for the rationale.
   const { error, status } = spawnSync('pnpm', ['store', 'prune'], {
     stdio: 'inherit',
     shell: true,
-    env: patchPnpmEnv(inputs),
   })
   endGroup()
 

src/utils/index.ts

@@ -1,10 +0,0 @@
-import path from 'path'
-import process from 'process'
-import { Inputs } from '../inputs'
-
-export const getBinDest = (inputs: Inputs): string => path.join(inputs.dest, 'node_modules', '.bin')
-
-export const patchPnpmEnv = (inputs: Inputs): NodeJS.ProcessEnv => ({
-  ...process.env,
-  PATH: path.join(getBinDest(inputs), 'bin') + path.delimiter + getBinDest(inputs) + path.delimiter + process.env.PATH,
-})