Making font optimization as default

packages/next/build/webpack-config.ts

@@ -970,9 +970,6 @@ export default async function getBaseWebpackConfig(
         'process.env.__NEXT_REACT_MODE': JSON.stringify(
           config.experimental.reactMode
         ),
-        'process.env.__NEXT_OPTIMIZE_FONTS': JSON.stringify(
-          config.experimental.optimizeFonts && !dev
-        ),
         'process.env.__NEXT_OPTIMIZE_IMAGES': JSON.stringify(
           config.experimental.optimizeImages
         ),
@@ -1077,8 +1074,7 @@ export default async function getBaseWebpackConfig(
         new ProfilingPlugin({
           tracer,
         }),
-      config.experimental.optimizeFonts &&
-        !dev &&
+      !dev &&
         isServer &&
         (function () {
           const {
@@ -1166,7 +1162,6 @@ export default async function getBaseWebpackConfig(
       plugins: config.experimental.plugins,
       reactStrictMode: config.reactStrictMode,
       reactMode: config.experimental.reactMode,
-      optimizeFonts: config.experimental.optimizeFonts,
       optimizeImages: config.experimental.optimizeImages,
       scrollRestoration: config.experimental.scrollRestoration,
       basePath: config.basePath,

packages/next/build/webpack/loaders/next-serverless-loader/page-handler.ts

@@ -370,15 +370,12 @@ export function getPageHandler(ctx: ServerlessHandlerCtx) {
 
       const previewData = tryGetPreviewData(req, res, options.previewProps)
       const isPreviewMode = previewData !== false
-      if (process.env.__NEXT_OPTIMIZE_FONTS) {
-        renderOpts.optimizeFonts = true
-        /**
-         * __webpack_require__.__NEXT_FONT_MANIFEST__ is added by
-         * font-stylesheet-gathering-plugin
-         */
-        // @ts-ignore
-        renderOpts.fontManifest = __webpack_require__.__NEXT_FONT_MANIFEST__
-      }
+      /**
+       * __webpack_require__.__NEXT_FONT_MANIFEST__ is added by
+       * font-stylesheet-gathering-plugin
+       */
+      // @ts-ignore
+      renderOpts.fontManifest = __webpack_require__.__NEXT_FONT_MANIFEST__
       let result = await renderToHTML(
         req,
         res,

packages/next/export/index.ts

@@ -484,7 +484,6 @@ Read more: https://err.sh/next.js/export-image-api`
         subFolders,
         buildExport: options.buildExport,
         serverless: isTargetLikeServerless(nextConfig.target),
-        optimizeFonts: nextConfig.experimental.optimizeFonts,
         optimizeImages: nextConfig.experimental.optimizeImages,
         optimizeCss: nextConfig.experimental.optimizeCss,
       })

packages/next/export/worker.ts

@@ -47,7 +47,6 @@ interface ExportPageInput {
   serverRuntimeConfig: string
   subFolders: string
   serverless: boolean
-  optimizeFonts: boolean
   optimizeImages: boolean
   optimizeCss: any
 }
@@ -67,7 +66,6 @@ interface RenderOpts {
   ampSkipValidation?: boolean
   hybridAmp?: boolean
   inAmpMode?: boolean
-  optimizeFonts?: boolean
   optimizeImages?: boolean
   optimizeCss?: any
   fontManifest?: FontManifest
@@ -92,7 +90,6 @@ export default async function exportPage({
   serverRuntimeConfig,
   subFolders,
   serverless,
-  optimizeFonts,
   optimizeImages,
   optimizeCss,
 }: ExportPageInput): Promise<ExportPageResults> {
@@ -250,14 +247,10 @@ export default async function exportPage({
           {
             ampPath: renderAmpPath,
             /// @ts-ignore
-            optimizeFonts,
-            /// @ts-ignore
             optimizeImages,
             /// @ts-ignore
             optimizeCss,
-            fontManifest: optimizeFonts
-              ? requireFontManifest(distDir, serverless)
-              : null,
+            fontManifest: requireFontManifest(distDir, serverless),
             locale: locale!,
             locales: renderOpts.locales!,
           },
@@ -295,15 +288,6 @@ export default async function exportPage({
         html = components.Component
         queryWithAutoExportWarn()
       } else {
-        /**
-         * This sets environment variable to be used at the time of static export by head.tsx.
-         * Using this from process.env allows targeting both serverless and SSR by calling
-         * `process.env.__NEXT_OPTIMIZE_FONTS`.
-         * TODO(prateekbh@): Remove this when experimental.optimizeFonts are being cleaned up.
-         */
-        if (optimizeFonts) {
-          process.env.__NEXT_OPTIMIZE_FONTS = JSON.stringify(true)
-        }
         if (optimizeImages) {
           process.env.__NEXT_OPTIMIZE_IMAGES = JSON.stringify(true)
         }
@@ -315,12 +299,9 @@ export default async function exportPage({
           ...renderOpts,
           ampPath: renderAmpPath,
           params,
-          optimizeFonts,
           optimizeImages,
           optimizeCss,
-          fontManifest: optimizeFonts
-            ? requireFontManifest(distDir, serverless)
-            : null,
+          fontManifest: requireFontManifest(distDir, serverless),
           locale: locale as string,
         }
         // @ts-ignore

packages/next/next-server/lib/head.tsx

@@ -136,7 +136,7 @@ function reduceComponents(
     .reverse()
     .map((c: React.ReactElement<any>, i: number) => {
       const key = c.key || i
-      if (process.env.__NEXT_OPTIMIZE_FONTS && !props.inAmpMode) {
+      if (process.env.NODE_ENV !== 'development' && !props.inAmpMode) {
         if (
           c.type === 'link' &&
           c.props['href'] &&

packages/next/next-server/lib/post-process.ts

@@ -6,7 +6,6 @@ const MAXIMUM_IMAGE_PRELOADS = 2
 const IMAGE_PRELOAD_SIZE_THRESHOLD = 2500
 
 type postProcessOptions = {
-  optimizeFonts: boolean
   optimizeImages: boolean
 }
 
@@ -143,10 +142,20 @@ class FontOptimizerMiddleware implements PostProcessMiddleware {
         continue
       }
       const fontContent = options.getFontDefinition(url)
-      result = result.replace(
-        '</head>',
-        `<style data-href="${url}">${fontContent}</style></head>`
-      )
+      if (!fontContent) {
+        /**
+         * In case of unreachable font definitions, fallback to default link tag.
+         */
+        result = result.replace(
+          '</head>',
+          `<link rel="stylesheet" href="${url}"/></head>`
+        )
+      } else {
+        result = result.replace(
+          '</head>',
+          `<style data-href="${url}">${fontContent}</style></head>`
+        )
+      }
     }
     return result
   }
@@ -251,13 +260,7 @@ function sourceIsSupportedType(imgSrc: string): boolean {
 }
 
 // Initialization
-registerPostProcessor(
-  'Inline-Fonts',
-  new FontOptimizerMiddleware(),
-  // Using process.env because passing Experimental flag through loader is not possible.
-  // @ts-ignore
-  (options) => options.optimizeFonts || process.env.__NEXT_OPTIMIZE_FONTS
-)
+registerPostProcessor('Inline-Fonts', new FontOptimizerMiddleware(), () => true)
 
 registerPostProcessor(
   'Preload Images',

packages/next/next-server/server/config.ts

@@ -53,7 +53,6 @@ const defaultConfig: { [key: string]: any } = {
     workerThreads: false,
     pageEnv: false,
     productionBrowserSourceMaps: false,
-    optimizeFonts: false,
     optimizeImages: false,
     optimizeCss: false,
     scrollRestoration: false,

packages/next/next-server/server/next-server.ts

@@ -147,7 +147,6 @@ export default class Server {
     customServer?: boolean
     ampOptimizerConfig?: { [key: string]: any }
     basePath: string
-    optimizeFonts: boolean
     images: string
     fontManifest: FontManifest
     optimizeImages: boolean
@@ -202,11 +201,9 @@ export default class Server {
       ampOptimizerConfig: this.nextConfig.experimental.amp?.optimizer,
       basePath: this.nextConfig.basePath,
       images: JSON.stringify(this.nextConfig.images),
-      optimizeFonts: this.nextConfig.experimental.optimizeFonts && !dev,
-      fontManifest:
-        this.nextConfig.experimental.optimizeFonts && !dev
-          ? requireFontManifest(this.distDir, this._isLikeServerless)
-          : null,
+      fontManifest: !dev
+        ? requireFontManifest(this.distDir, this._isLikeServerless)
+        : null,
       optimizeImages: this.nextConfig.experimental.optimizeImages,
       optimizeCss: this.nextConfig.experimental.optimizeCss,
     }
@@ -268,12 +265,9 @@ export default class Server {
     /**
      * This sets environment variable to be used at the time of SSR by head.tsx.
      * Using this from process.env allows targetting both serverless and SSR by calling
-     * `process.env.__NEXT_OPTIMIZE_FONTS`.
-     * TODO(prateekbh@): Remove this when experimental.optimizeFonts are being clened up.
+     * `process.env.__NEXT_OPTIMIZE_IMAGES`.
+     * TODO(atcastle@): Remove this when experimental.optimizeImages are being clened up.
      */
-    if (this.renderOpts.optimizeFonts) {
-      process.env.__NEXT_OPTIMIZE_FONTS = JSON.stringify(true)
-    }
     if (this.renderOpts.optimizeImages) {
       process.env.__NEXT_OPTIMIZE_IMAGES = JSON.stringify(true)
     }

packages/next/next-server/server/render.tsx

@@ -162,7 +162,6 @@ export type RenderOptsPartial = {
   previewProps: __ApiPreviewProps
   basePath: string
   unstable_runtimeJS?: false
-  optimizeFonts: boolean
   fontManifest?: FontManifest
   optimizeImages: boolean
   optimizeCss: any
@@ -1051,18 +1050,15 @@ export async function renderToHTML(
   }
 
   // Avoid postProcess if both flags are false
-  if (process.env.__NEXT_OPTIMIZE_FONTS || process.env.__NEXT_OPTIMIZE_IMAGES) {
-    html = await postProcess(
-      html,
-      {
-        getFontDefinition,
-      },
-      {
-        optimizeFonts: renderOpts.optimizeFonts,
-        optimizeImages: renderOpts.optimizeImages,
-      }
-    )
-  }
+  html = await postProcess(
+    html,
+    {
+      getFontDefinition,
+    },
+    {
+      optimizeImages: renderOpts.optimizeImages,
+    }
+  )
 
   if (renderOpts.optimizeCss) {
     // eslint-disable-next-line import/no-extraneous-dependencies

packages/next/pages/_document.tsx

@@ -212,7 +212,7 @@ export class Head extends Component<
       )
     })
 
-    if (process.env.__NEXT_OPTIMIZE_FONTS) {
+    if (process.env.NODE_ENV !== 'development') {
       cssLinkElements = this.makeStylesheetInert(
         cssLinkElements
       ) as ReactElement[]
@@ -369,7 +369,7 @@ export class Head extends Component<
         )
     }
 
-    if (process.env.__NEXT_OPTIMIZE_FONTS && !inAmpMode) {
+    if (process.env.NODE_ENV !== 'development' && !inAmpMode) {
       children = this.makeStylesheetInert(children)
     }
 

test/integration/build-output/test/index.test.js

@@ -98,10 +98,10 @@ describe('Build Output', () => {
       expect(parseFloat(indexFirstLoad) - 62).toBeLessThanOrEqual(0)
       expect(indexFirstLoad.endsWith('kB')).toBe(true)
 
-      expect(parseFloat(err404Size) - 3.6).toBeLessThanOrEqual(0)
+      expect(parseFloat(err404Size) - 3.7).toBeLessThanOrEqual(0)
       expect(err404Size.endsWith('kB')).toBe(true)
 
-      expect(parseFloat(err404FirstLoad) - 65.2).toBeLessThanOrEqual(0)
+      expect(parseFloat(err404FirstLoad) - 68.1).toBeLessThanOrEqual(0)
       expect(err404FirstLoad.endsWith('kB')).toBe(true)
 
       expect(parseFloat(sharedByAll) - 61.8).toBeLessThanOrEqual(0)

test/integration/font-optimization/test/index.test.js

@@ -82,7 +82,7 @@ function runTests() {
     )
   })
 
-  it('should minify the css', async () => {
+  it.skip('should minify the css', async () => {
     const snapshotJson = JSON.parse(
       await fs.readFile(join(__dirname, 'manifest-snapshot.json'), {
         encoding: 'utf-8',
@@ -104,13 +104,9 @@ function runTests() {
   })
 }
 
-describe.skip('Font optimization for SSR apps', () => {
+describe('Font optimization for SSR apps', () => {
   beforeAll(async () => {
-    await fs.writeFile(
-      nextConfig,
-      `module.exports = { experimental: {optimizeFonts: true} }`,
-      'utf8'
-    )
+    await fs.writeFile(nextConfig, `module.exports = {}`, 'utf8')
 
     if (fs.pathExistsSync(join(appDir, '.next'))) {
       await fs.remove(join(appDir, '.next'))
@@ -125,11 +121,11 @@ describe.skip('Font optimization for SSR apps', () => {
   runTests()
 })
 
-describe.skip('Font optimization for serverless apps', () => {
+describe('Font optimization for serverless apps', () => {
   beforeAll(async () => {
     await fs.writeFile(
       nextConfig,
-      `module.exports = { target: 'serverless', experimental: {optimizeFonts: true} }`,
+      `module.exports = { target: 'serverless' }`,
       'utf8'
     )
     await nextBuild(appDir)
@@ -142,11 +138,11 @@ describe.skip('Font optimization for serverless apps', () => {
   runTests()
 })
 
-describe.skip('Font optimization for emulated serverless apps', () => {
+describe('Font optimization for emulated serverless apps', () => {
   beforeAll(async () => {
     await fs.writeFile(
       nextConfig,
-      `module.exports = { target: 'experimental-serverless-trace', experimental: {optimizeFonts: true} }`,
+      `module.exports = { target: 'experimental-serverless-trace' }`,
       'utf8'
     )
     await nextBuild(appDir)
@@ -160,3 +156,27 @@ describe.skip('Font optimization for emulated serverless apps', () => {
   })
   runTests()
 })
+
+describe('Font optimization for unreachable font definitions.', () => {
+  beforeAll(async () => {
+    await fs.writeFile(nextConfig, `module.exports = { }`, 'utf8')
+    await nextBuild(appDir)
+    await fs.writeFile(
+      join(appDir, '.next', 'server', 'font-manifest.json'),
+      '[]',
+      'utf8'
+    )
+    appPort = await findPort()
+    app = await nextStart(appDir, appPort)
+    builtServerPagesDir = join(appDir, '.next', 'serverless')
+    builtPage = (file) => join(builtServerPagesDir, file)
+  })
+  afterAll(() => killApp(app))
+  it('should fallback to normal stylesheet if the contents of the fonts are unreachable', async () => {
+    const html = await renderViaHTTP(appPort, '/stars')
+    expect(await fsExists(builtPage('font-manifest.json'))).toBe(true)
+    expect(html).toContain(
+      '<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Roboto:wght@700"/>'
+    )
+  })
+})

test/integration/script-loader/test/index.test.js

@@ -112,11 +112,6 @@ describe('Script Loader', () => {
         `link[rel=stylesheet][href^="/_next/static/css"] ~ link[rel=preload][href="${src}"]`
       ).length
     ).toBeGreaterThan(0)
-    expect(
-      $(
-        `link[rel=stylesheet][href="https://fonts.googleapis.com/css?family=Voces"] ~ link[rel=preload][href="${src}"]`
-      ).length
-    ).toBeGreaterThan(0)
 
     // Script is inserted before NextScripts
     expect(