fix(desktop): give pnpm deploy a workspace-relative staging target

pnpm joins its workspace root with the deploy target instead of resolving it,
so an absolute path on another volume became D:\repo\C:\Users\... and the
Windows job failed with ERR_PNPM_ENOENT. A relative target is correct whether
pnpm joins or resolves, and cannot cross a drive letter, so the staging
directory moves onto the repository's own volume.

Author: elkaix

.changeset/desktop-windows-deploy-target.md

@@ -0,0 +1,5 @@
+---
+'@pymodel/pythinker-desktop': patch
+---
+
+Stage the desktop Host closure inside the workspace so pnpm deploy resolves the target on Windows

apps/desktop/scripts/stage-runtime.ts

@@ -3,8 +3,7 @@
 import { spawn } from 'node:child_process'
 import { existsSync } from 'node:fs'
 import { cp, lstat, mkdir, mkdtemp, readFile, readdir, realpath, rm, writeFile } from 'node:fs/promises'
-import { tmpdir } from 'node:os'
-import { join, resolve, sep } from 'node:path'
+import { join, relative, resolve, sep } from 'node:path'
 import { fileURLToPath } from 'node:url'
 
 const desktopRoot = resolve(import.meta.dirname, '..')
@@ -14,6 +13,7 @@ const deployPackage = '@pymodel/pythinker-code'
 const entry = join(staging, 'node_modules/@pymodel/pythinker-code/dist/launcher.mjs')
 const frontend = join(staging, 'node_modules/@pymodel/pythinker-code/dist-web/index.html')
 const workspaceState = join(repositoryRoot, 'node_modules/.pnpm-workspace-state-v1.json')
+const stagingParent = join(repositoryRoot, 'node_modules', '.pythinker-desktop-staging')
 
 /** Windows characters that make an argument unsafe to hand to `cmd.exe` unquoted. */
 const WINDOWS_UNSAFE_ARGUMENT = /[\s"&()<>^|]/u
@@ -42,6 +42,21 @@ export function packageManagerInvocation(platform: string, command: string, args
   }
 }
 
+/**
+ * Express a deploy target the way pnpm accepts it.
+ *
+ * pnpm joins its workspace root with the deploy target rather than resolving
+ * it, so an absolute path on another volume produces a concatenated,
+ * non-existent directory such as `D:\repo\C:\Users\…`. A workspace-relative
+ * target is correct whether pnpm joins or resolves.
+ * @param workspaceRoot - The pnpm workspace root, and the child process's cwd.
+ * @param target - The absolute staging directory.
+ * @returns The target expressed relative to the workspace root.
+ */
+export function deployTargetArgument(workspaceRoot: string, target: string): string {
+  return relative(workspaceRoot, target)
+}
+
 async function run(command: string, args: readonly string[]): Promise<void> {
   const invocation = packageManagerInvocation(process.platform, command, args)
   await new Promise<void>((accept, reject) => {
@@ -96,7 +111,8 @@ async function deploy(target: string): Promise<void> {
   try {
     await run('pnpm', [
       '--config.verify-deps-before-run=false', '--filter', deployPackage, 'deploy', '--legacy', '--prod',
-      '--config.node-linker=hoisted', '--config.auto-install-peers=false', '--config.link-workspace-packages=true', target,
+      '--config.node-linker=hoisted', '--config.auto-install-peers=false', '--config.link-workspace-packages=true',
+      deployTargetArgument(repositoryRoot, target),
     ])
   } finally {
     if (savedWorkspaceState === undefined) await rm(workspaceState, { force: true })
@@ -105,7 +121,8 @@ async function deploy(target: string): Promise<void> {
 }
 
 async function main(): Promise<void> {
-  const deployed = await mkdtemp(join(tmpdir(), 'pythinker-desktop-runtime-'))
+  await mkdir(stagingParent, { recursive: true })
+  const deployed = await mkdtemp(join(stagingParent, 'runtime-'))
   try {
     await deploy(deployed)
     await rm(join(staging, 'node_modules'), { recursive: true, force: true })

apps/desktop/tests/stage-runtime.spec.ts

@@ -1,5 +1,6 @@
+import { isAbsolute, join } from 'node:path'
 import { describe, expect, it } from 'vitest'
-import { packageManagerInvocation } from '../scripts/stage-runtime'
+import { deployTargetArgument, packageManagerInvocation } from '../scripts/stage-runtime'
 
 describe('package manager invocation', () => {
   it('leaves non-Windows invocations untouched', () => {
@@ -31,3 +32,21 @@ describe('package manager invocation', () => {
       .toEqual(['"deploy&verify"'])
   })
 })
+
+describe('deploy target argument', () => {
+  it('is relative to the workspace root', () => {
+    expect(deployTargetArgument('/repo', '/repo/node_modules/.pythinker-desktop-staging/runtime-abc123'))
+      .toBe(join('node_modules', '.pythinker-desktop-staging', 'runtime-abc123'))
+  })
+
+  it('is never absolute', () => {
+    expect(isAbsolute(deployTargetArgument('/repo', '/repo/node_modules/.pythinker-desktop-staging/runtime-abc123')))
+      .toBe(false)
+  })
+
+  it('never returns the target unchanged', () => {
+    const target = '/repo/node_modules/.pythinker-desktop-staging/runtime-abc123'
+
+    expect(deployTargetArgument('/repo', target)).not.toBe(target)
+  })
+})