Remove optimizeFonts (Automatic font optimization) superseded by ne…

…xt/font (#69137)

## What?

The `optimizeFonts` optimization has been replaced by `next/font` for
almost 2 years and was already no longer documented. This PR cleans up
the code related to it. It's recommended to use `next/font` as it's
better in every way, ensuring you get preloading of the font but also a
local fallback and better fallbacks.

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packages/next/src/build/flying-shuttle/stitch-builds.ts

@@ -17,7 +17,6 @@ import {
   APP_BUILD_MANIFEST,
   APP_PATH_ROUTES_MANIFEST,
   APP_PATHS_MANIFEST,
-  AUTOMATIC_FONT_OPTIMIZATION_MANIFEST,
   BUILD_MANIFEST,
   CLIENT_REFERENCE_MANIFEST,
   FUNCTIONS_CONFIG_MANIFEST,
@@ -366,22 +365,6 @@ export async function stitchBuilds(
     )}`
   )
 
-  // for server/font-manifest.json we just merge the arrays
-  for (const file of [AUTOMATIC_FONT_OPTIMIZATION_MANIFEST]) {
-    const [restoreFontManifest, currentFontManifest] = await Promise.all(
-      [
-        path.join(shuttleDir, 'server', file),
-        path.join(distDir, 'server', file),
-      ].map(async (f) => JSON.parse(await fs.promises.readFile(f, 'utf8')))
-    )
-    const mergedFontManifest = [...restoreFontManifest, ...currentFontManifest]
-
-    await fs.promises.writeFile(
-      path.join(distDir, 'server', file),
-      JSON.stringify(mergedFontManifest, null, 2)
-    )
-  }
-
   // for server/functions-config-manifest.json we just merge
   // the functions field
   const [restoreFunctionsConfigManifest, currentFunctionsConfigManifest] =

packages/next/src/build/index.ts

@@ -52,7 +52,6 @@ import {
   CLIENT_STATIC_FILES_PATH,
   EXPORT_DETAIL,
   EXPORT_MARKER,
-  AUTOMATIC_FONT_OPTIMIZATION_MANIFEST,
   IMAGES_MANIFEST,
   PAGES_MANIFEST,
   PHASE_PRODUCTION_BUILD,
@@ -2342,12 +2341,6 @@ export default async function build(
                   ]
                 : []),
               REACT_LOADABLE_MANIFEST,
-              config.optimizeFonts
-                ? path.join(
-                    SERVER_DIRECTORY,
-                    AUTOMATIC_FONT_OPTIMIZATION_MANIFEST
-                  )
-                : null,
               BUILD_ID_FILE,
               path.join(SERVER_DIRECTORY, NEXT_FONT_MANIFEST + '.js'),
               path.join(SERVER_DIRECTORY, NEXT_FONT_MANIFEST + '.json'),
@@ -2469,10 +2462,6 @@ export default async function build(
           featureName: 'experimental/nextScriptWorkers',
           invocationCount: config.experimental.nextScriptWorkers ? 1 : 0,
         },
-        {
-          featureName: 'optimizeFonts',
-          invocationCount: config.optimizeFonts ? 1 : 0,
-        },
         {
           featureName: 'experimental/ppr',
           invocationCount: config.experimental.ppr ? 1 : 0,

packages/next/src/build/webpack-config.ts

@@ -1856,20 +1856,6 @@ export default async function getBaseWebpackConfig(
           clientRouterFilters,
         }),
       new ProfilingPlugin({ runWebpackSpan, rootDir: dir }),
-      config.optimizeFonts &&
-        !dev &&
-        isNodeServer &&
-        (function () {
-          const { FontStylesheetGatheringPlugin } =
-            require('./webpack/plugins/font-stylesheet-gathering-plugin') as {
-              FontStylesheetGatheringPlugin: typeof import('./webpack/plugins/font-stylesheet-gathering-plugin').FontStylesheetGatheringPlugin
-            }
-          return new FontStylesheetGatheringPlugin({
-            adjustFontFallbacks: config.experimental.adjustFontFallbacks,
-            adjustFontFallbacksWithSizeAdjust:
-              config.experimental.adjustFontFallbacksWithSizeAdjust,
-          })
-        })(),
       new WellKnownErrorsPlugin(),
       isClient &&
         new CopyFilePlugin({
@@ -2071,7 +2057,6 @@ export default async function getBaseWebpackConfig(
     buildActivityPosition: config.devIndicators.buildActivityPosition,
     productionBrowserSourceMaps: !!config.productionBrowserSourceMaps,
     reactStrictMode: config.reactStrictMode,
-    optimizeFonts: config.optimizeFonts,
     optimizeCss: config.experimental.optimizeCss,
     nextScriptWorkers: config.experimental.nextScriptWorkers,
     scrollRestoration: config.experimental.scrollRestoration,

packages/next/src/build/webpack/plugins/define-env-plugin.ts

@@ -235,7 +235,6 @@ export function getDefineEnv({
     'process.env.__NEXT_STRICT_MODE_APP':
       // When next.config.js does not have reactStrictMode it's enabled by default.
       config.reactStrictMode === null ? true : config.reactStrictMode,
-    'process.env.__NEXT_OPTIMIZE_FONTS': !dev && config.optimizeFonts,
     'process.env.__NEXT_OPTIMIZE_CSS':
       (config.experimental.optimizeCss && !dev) ?? false,
     'process.env.__NEXT_SCRIPT_WORKERS':

packages/next/src/export/index.ts

@@ -44,7 +44,6 @@ import { loadEnvConfig } from '@next/env'
 import { isAPIRoute } from '../lib/is-api-route'
 import { getPagePath } from '../server/require'
 import type { Span } from '../trace'
-import type { FontConfig } from '../server/font-utils'
 import type { MiddlewareManifest } from '../build/webpack/plugins/middleware-plugin'
 import { isAppRouteRoute } from '../lib/is-app-route-route'
 import { isAppPageRoute } from '../lib/is-app-page-route'
@@ -340,7 +339,6 @@ async function exportAppImpl(
     optimizeCss: nextConfig.experimental.optimizeCss,
     nextConfigOutput: nextConfig.output,
     nextScriptWorkers: nextConfig.experimental.nextScriptWorkers,
-    optimizeFonts: nextConfig.optimizeFonts as FontConfig,
     largePageDataBytes: nextConfig.experimental.largePageDataBytes,
     serverActions: nextConfig.experimental.serverActions,
     serverComponents: enabledDirectories.app,

packages/next/src/export/routes/pages.ts

@@ -87,16 +87,10 @@ export async function exportPagesPage(
     }
   } else {
     /**
-     * This sets environment variable to be used at the time of static export by head.tsx.
+     * This sets environment variable to be used at the time of SSR by head.tsx.
      * Using this from process.env allows targeting SSR by calling
-     * `process.env.__NEXT_OPTIMIZE_FONTS`.
-     * TODO(prateekbh@): Remove this when experimental.optimizeFonts are being cleaned up.
+     * `process.env.__NEXT_OPTIMIZE_CSS`.
      */
-    if (renderOpts.optimizeFonts) {
-      process.env.__NEXT_OPTIMIZE_FONTS = JSON.stringify(
-        renderOpts.optimizeFonts
-      )
-    }
     if (renderOpts.optimizeCss) {
       process.env.__NEXT_OPTIMIZE_CSS = JSON.stringify(true)
     }