fix(nuxt): make shared/ directories available within layers (#30843)

packages/nuxt/src/core/nitro.ts

@@ -49,7 +49,19 @@ export async function initNitro (nuxt: Nuxt & { _nitro?: Nitro }) {
       .map(m => m.entryPath!),
   )
 
+  const sharedDirs = new Set<string>()
   const isNuxtV4 = nuxt.options.future?.compatibilityVersion === 4
+  if (isNuxtV4 && (nuxt.options.nitro.imports !== false && nuxt.options.imports.scan !== false)) {
+    for (const layer of nuxt.options._layers) {
+      // Layer disabled scanning for itself
+      if (layer.config?.imports?.scan === false) {
+        continue
+      }
+
+      sharedDirs.add(resolve(layer.config.rootDir, 'shared', 'utils'))
+      sharedDirs.add(resolve(layer.config.rootDir, 'shared', 'types'))
+    }
+  }
 
   const nitroConfig: NitroConfig = defu(nuxt.options.nitro, {
     debug: nuxt.options.debug ? nuxt.options.debug.nitro : false,
@@ -68,12 +80,7 @@ export async function initNitro (nuxt: Nuxt & { _nitro?: Nitro }) {
     },
     imports: {
       autoImport: nuxt.options.imports.autoImport as boolean,
-      dirs: isNuxtV4
-        ? [
-            resolve(nuxt.options.rootDir, 'shared', 'utils'),
-            resolve(nuxt.options.rootDir, 'shared', 'types'),
-          ]
-        : [],
+      dirs: [...sharedDirs],
       imports: [
         {
           as: '__buildAssetsURL',

packages/nuxt/test/shared-dir-config.test.ts

@@ -0,0 +1,57 @@
+import { fileURLToPath } from 'node:url'
+import { describe, expect, it } from 'vitest'
+import { normalize } from 'pathe'
+import type { NuxtConfig } from '@nuxt/schema'
+import { loadNuxt } from '../src'
+
+const fixtureDir = normalize(fileURLToPath(new URL('../../../test/fixtures/basic', import.meta.url)))
+
+describe('loadNuxt', () => {
+  it('does not add shared directories to nitro auto-imports in v3', async () => {
+    const importDirs = await getNitroImportDirs({ future: { compatibilityVersion: 3 as any } })
+    expect(normalizePaths(importDirs)).toMatchInlineSnapshot(`[]`)
+  })
+  it('adds shared directories for layers to nitro auto-imports in v4', async () => {
+    const importDirs = await getNitroImportDirs({ future: { compatibilityVersion: 4 } })
+    expect(normalizePaths(importDirs)).toMatchInlineSnapshot(`
+      [
+        "<rootDir>/shared/utils",
+        "<rootDir>/shared/types",
+        "<rootDir>/extends/bar/shared/utils",
+        "<rootDir>/extends/bar/shared/types",
+        "<rootDir>/extends/node_modules/foo/shared/utils",
+        "<rootDir>/extends/node_modules/foo/shared/types",
+        "<rootDir>/layers/bar/shared/utils",
+        "<rootDir>/layers/bar/shared/types",
+      ]
+    `)
+  })
+})
+
+function normalizePaths (arr: unknown[]) {
+  const normalized = []
+  for (const dir of arr) {
+    normalized.push(typeof dir === 'string' ? dir.replace(fixtureDir, '<rootDir>') : dir)
+  }
+  return normalized
+}
+
+async function getNitroImportDirs (overrides?: NuxtConfig) {
+  const importDirs: unknown[] = []
+  const nuxt = await loadNuxt({
+    cwd: fixtureDir,
+    ready: true,
+    overrides: {
+      ...overrides,
+      hooks: {
+        'nitro:config' (config) {
+          if (config.imports) {
+            importDirs.push(...config.imports.dirs || [])
+          }
+        },
+      },
+    },
+  })
+  await nuxt.close()
+  return importDirs
+}