fix(desktop): refuse the build when ANY declared non-optional dep is missing

Widen the salvaged guard from a hand-maintained four-package floor to the
class it stands for: every `dependencies` + `devDependencies` entry in the
desktop workspace manifest. Live probe on this box: a tree holding vite,
katex, electron and electron-builder but missing `@rolldown/plugin-babel`
still passed the floor-only guard, and `vite build` died loading
`vite.config.ts` after `prebuild` had already run. The floor stays as an
unconditional fallback for an unreadable manifest; optionalDependencies
are skipped because npm legitimately omits them (get-windows).

Five new vitest cases (12 total); the two class tests fail when the
manifest union is removed. Refs #86443.

apps/desktop/scripts/assert-root-install.mjs

@@ -31,13 +31,25 @@ import { isMain } from "./utils.mjs"
 // others, which is how an incomplete install reached `vite build` and died on
 // an unresolved `katex/dist/katex.min.css` with no hint that the install — not
 // the source — was at fault (#86443).
+//
+// These four are the documented floor — always checked, even when the app's
+// package.json cannot be read. The full class is wider: EVERY non-optional
+// package the workspace manifest declares is something the build may import
+// (`vite.config.ts` pulls `@rolldown/plugin-babel`, `@vitejs/plugin-react`,
+// `@tailwindcss/vite`; `bundle-electron-main.mjs` pulls `esbuild`; the renderer
+// imports the rest). A hand-maintained list drifts the moment a new import
+// lands, so `checkRootInstall` unions the floor with the manifest's declared
+// `dependencies` + `devDependencies` — a partial install is refused whichever
+// package it happened to drop. `optionalDependencies` are excluded by design:
+// npm legitimately skips them (platform-gated natives like `get-windows`).
 const BUILD_CRITICAL_PACKAGES = ["vite", "katex", "electron", "electron-builder"]
 export { BUILD_CRITICAL_PACKAGES }
 
 // Resolve the way Node's own lookup does — walk `node_modules` upward — rather
 // than through `require.resolve`. A package whose `exports` map does not expose
 // `./package.json` is not resolvable by path even when correctly installed, and
-// that must not read as "missing".
+// that must not read as "missing". Scoped names (`@scope/name`) are a nested
+// directory under `node_modules`, which `join` handles.
 function packageIsInstalled(name, fromDir) {
   let dir = fromDir
   for (;;) {
@@ -48,10 +60,27 @@ function packageIsInstalled(name, fromDir) {
   }
 }
 
+// Every package the workspace manifest at `appDir` declares as required
+// (`dependencies` + `devDependencies`; never `optionalDependencies`). An
+// unreadable or malformed manifest yields [] — the floor still applies, and
+// the build's own manifest read fails loudly on its own.
+export function requiredPackages(appDir) {
+  try {
+    const manifest = JSON.parse(readFileSync(join(appDir, "package.json"), "utf8"))
+    return [
+      ...Object.keys(manifest.dependencies ?? {}),
+      ...Object.keys(manifest.devDependencies ?? {}),
+    ]
+  } catch {
+    return []
+  }
+}
+
 // Pure check — returns { ok: true } or { ok: false, error: "..." }.
 // Kept side-effect-free so it can be unit tested without spawning a process.
 export function checkRootInstall(appDir, rootDir) {
-  const missing = BUILD_CRITICAL_PACKAGES.filter(pkg => !packageIsInstalled(pkg, appDir))
+  const wanted = [...new Set([...BUILD_CRITICAL_PACKAGES, ...requiredPackages(appDir)])]
+  const missing = wanted.filter(pkg => !packageIsInstalled(pkg, appDir))
   if (missing.length > 0) {
     return {
       ok: false,

apps/desktop/scripts/assert-root-install.test.mjs

@@ -4,15 +4,17 @@ import os from 'node:os'
 import path from 'node:path'
 import { test } from 'vitest'
 
-import { BUILD_CRITICAL_PACKAGES as BUILD_CRITICAL, checkRootInstall } from '../scripts/assert-root-install.mjs'
+import { BUILD_CRITICAL_PACKAGES as BUILD_CRITICAL, checkRootInstall, requiredPackages } from '../scripts/assert-root-install.mjs'
 
 // Build a throwaway repo shaped like this one: an app workspace whose
 // dependencies are hoisted to the repo root, which is what the guard walks.
-function makeTree({ rootPackages = BUILD_CRITICAL, react = '19.2.7', reactDom = '19.2.7' } = {}) {
+// `manifest` is merged into the app's package.json so tests can declare
+// dependencies the guard is expected to read.
+function makeTree({ rootPackages = BUILD_CRITICAL, react = '19.2.7', reactDom = '19.2.7', manifest = {} } = {}) {
   const tempRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'hermes-assert-root-'))
   const appDir = path.join(tempRoot, 'apps', 'desktop')
   fs.mkdirSync(appDir, { recursive: true })
-  fs.writeFileSync(path.join(appDir, 'package.json'), JSON.stringify({ name: 'desktop' }), 'utf8')
+  fs.writeFileSync(path.join(appDir, 'package.json'), JSON.stringify({ name: 'desktop', ...manifest }), 'utf8')
 
   const writePackage = (name, version) => {
     const dir = path.join(tempRoot, 'node_modules', name)
@@ -120,3 +122,76 @@ test('checkRootInstall accepts a package nested in the app workspace', () => {
     fs.rmSync(tempRoot, { recursive: true, force: true })
   }
 })
+
+// The class, not the four instances: the floor list is what a partial install
+// has been *seen* to drop, but any declared non-optional package can be the one
+// missing next (`vite.config.ts` imports `@rolldown/plugin-babel`, which the
+// floor never named). The guard must read the manifest so the list cannot drift
+// behind a new import.
+test('checkRootInstall fails when a declared devDependency outside the floor is missing', () => {
+  const { tempRoot, appDir } = makeTree({
+    manifest: { devDependencies: { '@rolldown/plugin-babel': '1.0.0', esbuild: '1.0.0' } },
+    rootPackages: [...BUILD_CRITICAL, 'esbuild']
+  })
+  try {
+    const result = checkRootInstall(appDir, tempRoot)
+    assert.equal(result.ok, false)
+    assert.match(result.error, /@rolldown\/plugin-babel/)
+    assert.doesNotMatch(result.error, /esbuild/)
+  } finally {
+    fs.rmSync(tempRoot, { recursive: true, force: true })
+  }
+})
+
+test('checkRootInstall fails when a declared runtime dependency is missing', () => {
+  const { tempRoot, appDir } = makeTree({
+    manifest: { dependencies: { '@vscode/codicons': '1.0.0' } }
+  })
+  try {
+    const result = checkRootInstall(appDir, tempRoot)
+    assert.equal(result.ok, false)
+    assert.match(result.error, /@vscode\/codicons/)
+  } finally {
+    fs.rmSync(tempRoot, { recursive: true, force: true })
+  }
+})
+
+// npm skips optionalDependencies legitimately (platform-gated natives), so an
+// absent optional package is not a partial install.
+test('checkRootInstall ignores missing optionalDependencies', () => {
+  const { tempRoot, appDir } = makeTree({
+    manifest: { optionalDependencies: { 'get-windows': '9.3.0' } }
+  })
+  try {
+    assert.deepEqual(checkRootInstall(appDir, tempRoot), { ok: true })
+  } finally {
+    fs.rmSync(tempRoot, { recursive: true, force: true })
+  }
+})
+
+test('checkRootInstall passes when every declared package is installed', () => {
+  const { tempRoot, appDir } = makeTree({
+    manifest: { dependencies: { '@scope/pkg': '1.0.0' }, devDependencies: { esbuild: '1.0.0' } },
+    rootPackages: [...BUILD_CRITICAL, '@scope/pkg', 'esbuild']
+  })
+  try {
+    assert.deepEqual(checkRootInstall(appDir, tempRoot), { ok: true })
+  } finally {
+    fs.rmSync(tempRoot, { recursive: true, force: true })
+  }
+})
+
+// The floor is unconditional: a manifest the guard cannot parse must not turn
+// the check off.
+test('checkRootInstall keeps the floor when the manifest is unreadable', () => {
+  const { tempRoot, appDir } = makeTree({ rootPackages: ['vite'] })
+  fs.writeFileSync(path.join(appDir, 'package.json'), '{not json', 'utf8')
+  try {
+    assert.deepEqual(requiredPackages(appDir), [])
+    const result = checkRootInstall(appDir, tempRoot)
+    assert.equal(result.ok, false)
+    assert.match(result.error, /katex/)
+  } finally {
+    fs.rmSync(tempRoot, { recursive: true, force: true })
+  }
+})