Fix css dependency in /_error

packages/next/pages/_document.tsx

@@ -55,8 +55,7 @@ function getDocumentFiles(
   pathname: string
 ): DocumentFiles {
   const sharedFiles: readonly string[] = getPageFiles(buildManifest, '/_app')
-  const pageFiles: readonly string[] =
-    pathname !== '/_error' ? getPageFiles(buildManifest, pathname) : []
+  const pageFiles: readonly string[] = getPageFiles(buildManifest, pathname)
 
   return {
     sharedFiles,

test/integration/document-file-dependencies/css/app.css

@@ -0,0 +1,3 @@
+.global {
+  background-color: #eeeeee;
+}

test/integration/document-file-dependencies/css/error.module.css

@@ -0,0 +1,3 @@
+.error {
+  color: #ff0000;
+}

test/integration/document-file-dependencies/css/index.module.css

@@ -0,0 +1,3 @@
+.index {
+  color: #333333;
+}

test/integration/document-file-dependencies/pages/_app.js

@@ -0,0 +1,11 @@
+import '../css/app.css'
+
+function App({ Component, pageProps }) {
+  return (
+    <div className="global">
+      <Component {...pageProps} />
+    </div>
+  )
+}
+
+export default App

test/integration/document-file-dependencies/pages/_error.js

@@ -0,0 +1,5 @@
+import style from '../css/error.module.css'
+
+export default function Error() {
+  return <div className={style.error}>error</div>
+}

test/integration/document-file-dependencies/pages/error-trigger.js

@@ -0,0 +1,14 @@
+import style from '../css/index.module.css'
+
+function ErrorTrigger() {
+  return <div className={style.index}>error-trigger</div>
+}
+
+ErrorTrigger.getInitialProps = () => {
+  throw new Error('Intentional Error')
+
+  // eslint-disable-next-line no-unreachable
+  return {}
+}
+
+export default ErrorTrigger

test/integration/document-file-dependencies/pages/index.js

@@ -0,0 +1,5 @@
+import style from '../css/index.module.css'
+
+export default function Index() {
+  return <div className={style.index}>index</div>
+}

test/integration/document-file-dependencies/test/index.test.js

@@ -0,0 +1,50 @@
+/* eslint-env jest */
+
+import { join } from 'path'
+import {
+  fetchViaHTTP,
+  findPort,
+  killApp,
+  nextBuild,
+  nextStart,
+} from 'next-test-utils'
+import cheerio from 'cheerio'
+
+jest.setTimeout(1000 * 60 * 2)
+const appDir = join(__dirname, '..')
+
+let appPort
+let app
+
+describe('File Dependencies', () => {
+  describe('production mode', () => {
+    beforeAll(async () => {
+      appPort = await findPort()
+      await nextBuild(appDir)
+      app = await nextStart(appDir, appPort)
+    })
+
+    afterAll(() => killApp(app))
+
+    it('should depend on global and module css files in standard page', async () => {
+      const res = await fetchViaHTTP(appPort, '/')
+      const $ = cheerio.load(await res.text())
+      const cssFiles = $('link[rel="stylesheet"]')
+      expect(cssFiles.length).toBe(2)
+    })
+
+    it('should depend on global and module css files in 404 page', async () => {
+      const res = await fetchViaHTTP(appPort, '/__not_found__')
+      const $ = cheerio.load(await res.text())
+      const cssFiles = $('link[rel="stylesheet"]')
+      expect(cssFiles.length).toBe(2)
+    })
+
+    it('should depend on global and module css files in _error page', async () => {
+      const res = await fetchViaHTTP(appPort, '/error-trigger')
+      const $ = cheerio.load(await res.text())
+      const cssFiles = $('link[rel="stylesheet"]')
+      expect(cssFiles.length).toBe(2)
+    })
+  })
+})