index.ts

import { loadEnvConfig } from '@next/env'
import chalk from 'chalk'
import crypto from 'crypto'
import { promises, writeFileSync } from 'fs'
import Worker from 'jest-worker'
import devalue from 'next/dist/compiled/devalue'
import escapeStringRegexp from 'next/dist/compiled/escape-string-regexp'
import findUp from 'next/dist/compiled/find-up'
import { nanoid } from 'next/dist/compiled/nanoid/index.cjs'
import { pathToRegexp } from 'next/dist/compiled/path-to-regexp'
import path from 'path'
import formatWebpackMessages from '../client/dev/error-overlay/format-webpack-messages'
import {
  PAGES_404_GET_INITIAL_PROPS_ERROR,
  PUBLIC_DIR_MIDDLEWARE_CONFLICT,
} from '../lib/constants'
import { fileExists } from '../lib/file-exists'
import { findPagesDir } from '../lib/find-pages-dir'
import loadCustomRoutes, {
  getRedirectStatus,
  normalizeRouteRegex,
  Redirect,
  RouteType,
} from '../lib/load-custom-routes'
import { nonNullable } from '../lib/non-nullable'
import { recursiveDelete } from '../lib/recursive-delete'
import { verifyTypeScriptSetup } from '../lib/verifyTypeScriptSetup'
import {
  BUILD_ID_FILE,
  BUILD_MANIFEST,
  CLIENT_STATIC_FILES_PATH,
  EXPORT_DETAIL,
  EXPORT_MARKER,
  FONT_MANIFEST,
  IMAGES_MANIFEST,
  PAGES_MANIFEST,
  PHASE_PRODUCTION_BUILD,
  PRERENDER_MANIFEST,
  REACT_LOADABLE_MANIFEST,
  ROUTES_MANIFEST,
  SERVERLESS_DIRECTORY,
  SERVER_DIRECTORY,
  SERVER_FILES_MANIFEST,
} from '../next-server/lib/constants'
import {
  getRouteRegex,
  getSortedRoutes,
  isDynamicRoute,
} from '../next-server/lib/router/utils'
import { __ApiPreviewProps } from '../next-server/server/api-utils'
import loadConfig, {
  isTargetLikeServerless,
} from '../next-server/server/config'
import { BuildManifest } from '../next-server/server/get-page-files'
import '../next-server/server/node-polyfill-fetch'
import { normalizePagePath } from '../next-server/server/normalize-page-path'
import { getPagePath } from '../next-server/server/require'
import * as ciEnvironment from '../telemetry/ci-info'
import {
  eventBuildCompleted,
  eventBuildOptimize,
  eventCliSession,
  eventNextPlugins,
} from '../telemetry/events'
import { Telemetry } from '../telemetry/storage'
import { CompilerResult, runCompiler } from './compiler'
import { createEntrypoints, createPagesMapping } from './entries'
import { generateBuildId } from './generate-build-id'
import { isWriteable } from './is-writeable'
import * as Log from './output/log'
import createSpinner from './spinner'
import { traceAsyncFn, traceFn, tracer } from './tracer'
import {
  collectPages,
  getJsPageSizeInKb,
  getNamedExports,
  hasCustomGetInitialProps,
  isPageStatic,
  PageInfo,
  printCustomRoutes,
  printTreeView,
} from './utils'
import getBaseWebpackConfig from './webpack-config'
import { PagesManifest } from './webpack/plugins/pages-manifest-plugin'
import { writeBuildId } from './write-build-id'
import opentelemetryApi from '@opentelemetry/api'

const staticCheckWorker = require.resolve('./utils')

export type SsgRoute = {
  initialRevalidateSeconds: number | false
  srcRoute: string | null
  dataRoute: string
}

export type DynamicSsgRoute = {
  routeRegex: string
  fallback: string | null | false
  dataRoute: string
  dataRouteRegex: string
}

export type PrerenderManifest = {
  version: 2
  routes: { [route: string]: SsgRoute }
  dynamicRoutes: { [route: string]: DynamicSsgRoute }
  notFoundRoutes: string[]
  preview: __ApiPreviewProps
}

export default async function build(
  dir: string,
  conf = null,
  reactProductionProfiling = false,
  debugOutput = false
): Promise<void> {
  const span = tracer.startSpan('next-build')
  return traceAsyncFn(span, async () => {
    // attempt to load global env values so they are available in next.config.js
    const { loadedEnvFiles } = traceFn(tracer.startSpan('load-dotenv'), () =>
      loadEnvConfig(dir, false, Log)
    )

    const config = traceFn(tracer.startSpan('load-next-config'), () =>
      loadConfig(PHASE_PRODUCTION_BUILD, dir, conf)
    )
    const { target } = config
    const buildId = await traceAsyncFn(
      tracer.startSpan('generate-buildid'),
      () => generateBuildId(config.generateBuildId, nanoid)
    )
    const distDir = path.join(dir, config.distDir)

    const {
      headers,
      rewrites,
      redirects,
    } = await traceAsyncFn(tracer.startSpan('load-custom-routes'), () =>
      loadCustomRoutes(config)
    )

    if (ciEnvironment.isCI && !ciEnvironment.hasNextSupport) {
      const cacheDir = path.join(distDir, 'cache')
      const hasCache = await fileExists(cacheDir)

      if (!hasCache) {
        // Intentionally not piping to stderr in case people fail in CI when
        // stderr is detected.
        console.log(
          `${Log.prefixes.warn} No build cache found. Please configure build caching for faster rebuilds. Read more: https://err.sh/next.js/no-cache`
        )
      }
    }

    const buildSpinner = createSpinner({
      prefixText: `${Log.prefixes.info} Creating an optimized production build`,
    })

    const telemetry = new Telemetry({ distDir })

    const publicDir = path.join(dir, 'public')
    const pagesDir = findPagesDir(dir)
    const hasPublicDir = await fileExists(publicDir)

    telemetry.record(
      eventCliSession(PHASE_PRODUCTION_BUILD, dir, {
        cliCommand: 'build',
        isSrcDir: path.relative(dir, pagesDir!).startsWith('src'),
        hasNowJson: !!(await findUp('now.json', { cwd: dir })),
        isCustomServer: null,
      })
    )

    eventNextPlugins(path.resolve(dir)).then((events) =>
      telemetry.record(events)
    )

    const ignoreTypeScriptErrors = Boolean(config.typescript?.ignoreBuildErrors)
    await traceAsyncFn(tracer.startSpan('verify-typescript-setup'), () =>
      verifyTypeScriptSetup(dir, pagesDir, !ignoreTypeScriptErrors)
    )

    const isLikeServerless = isTargetLikeServerless(target)

    const pagePaths: string[] = await traceAsyncFn(
      tracer.startSpan('collect-pages'),
      () => collectPages(pagesDir, config.pageExtensions)
    )

    // needed for static exporting since we want to replace with HTML
    // files
    const allStaticPages = new Set<string>()
    let allPageInfos = new Map<string, PageInfo>()

    const previewProps: __ApiPreviewProps = {
      previewModeId: crypto.randomBytes(16).toString('hex'),
      previewModeSigningKey: crypto.randomBytes(32).toString('hex'),
      previewModeEncryptionKey: crypto.randomBytes(32).toString('hex'),
    }

    const mappedPages = traceFn(tracer.startSpan('create-pages-mapping'), () =>
      createPagesMapping(pagePaths, config.pageExtensions)
    )
    const entrypoints = traceFn(tracer.startSpan('create-entrypoints'), () =>
      createEntrypoints(
        mappedPages,
        target,
        buildId,
        previewProps,
        config,
        loadedEnvFiles
      )
    )
    const pageKeys = Object.keys(mappedPages)
    const conflictingPublicFiles: string[] = []
    const hasCustomErrorPage = mappedPages['/_error'].startsWith(
      'private-next-pages'
    )
    const hasPages404 = Boolean(
      mappedPages['/404'] &&
        mappedPages['/404'].startsWith('private-next-pages')
    )

    if (hasPublicDir) {
      const hasPublicUnderScoreNextDir = await fileExists(
        path.join(publicDir, '_next')
      )
      if (hasPublicUnderScoreNextDir) {
        throw new Error(PUBLIC_DIR_MIDDLEWARE_CONFLICT)
      }
    }

    await traceAsyncFn(
      tracer.startSpan('public-dir-conflict-check'),
      async () => {
        // Check if pages conflict with files in `public`
        // Only a page of public file can be served, not both.
        for (const page in mappedPages) {
          const hasPublicPageFile = await fileExists(
            path.join(publicDir, page === '/' ? '/index' : page),
            'file'
          )
          if (hasPublicPageFile) {
            conflictingPublicFiles.push(page)
          }
        }

        const numConflicting = conflictingPublicFiles.length

        if (numConflicting) {
          throw new Error(
            `Conflicting public and page file${
              numConflicting === 1 ? ' was' : 's were'
            } found. https://err.sh/vercel/next.js/conflicting-public-file-page\n${conflictingPublicFiles.join(
              '\n'
            )}`
          )
        }
      }
    )

    const nestedReservedPages = pageKeys.filter((page) => {
      return (
        page.match(/\/(_app|_document|_error)$/) && path.dirname(page) !== '/'
      )
    })

    if (nestedReservedPages.length) {
      Log.warn(
        `The following reserved Next.js pages were detected not directly under the pages directory:\n` +
          nestedReservedPages.join('\n') +
          `\nSee more info here: https://err.sh/next.js/nested-reserved-page\n`
      )
    }

    const buildCustomRoute = (
      r: {
        source: string
        locale?: false
        basePath?: false
        statusCode?: number
        destination?: string
      },
      type: RouteType
    ) => {
      const keys: any[] = []

      const routeRegex = pathToRegexp(r.source, keys, {
        strict: true,
        sensitive: false,
        delimiter: '/', // default is `/#?`, but Next does not pass query info
      })

      return {
        ...r,
        ...(type === 'redirect'
          ? {
              statusCode: getRedirectStatus(r as Redirect),
              permanent: undefined,
            }
          : {}),
        regex: normalizeRouteRegex(routeRegex.source),
      }
    }

    const routesManifestPath = path.join(distDir, ROUTES_MANIFEST)
    const routesManifest: {
      version: number
      pages404: boolean
      basePath: string
      redirects: Array<ReturnType<typeof buildCustomRoute>>
      rewrites: Array<ReturnType<typeof buildCustomRoute>>
      headers: Array<ReturnType<typeof buildCustomRoute>>
      dynamicRoutes: Array<{
        page: string
        regex: string
        namedRegex?: string
        routeKeys?: { [key: string]: string }
      }>
      dataRoutes: Array<{
        page: string
        routeKeys?: { [key: string]: string }
        dataRouteRegex: string
        namedDataRouteRegex?: string
      }>
      i18n?: {
        domains?: Array<{
          http?: true
          domain: string
          locales?: string[]
          defaultLocale: string
        }>
        locales: string[]
        defaultLocale: string
        localeDetection?: false
      }
    } = traceFn(tracer.startSpan('generate-routes-manifest'), () => ({
      version: 3,
      pages404: true,
      basePath: config.basePath,
      redirects: redirects.map((r) => buildCustomRoute(r, 'redirect')),
      rewrites: rewrites.map((r) => buildCustomRoute(r, 'rewrite')),
      headers: headers.map((r) => buildCustomRoute(r, 'header')),
      dynamicRoutes: getSortedRoutes(pageKeys)
        .filter(isDynamicRoute)
        .map((page) => {
          const routeRegex = getRouteRegex(page)
          return {
            page,
            regex: normalizeRouteRegex(routeRegex.re.source),
            routeKeys: routeRegex.routeKeys,
            namedRegex: routeRegex.namedRegex,
          }
        }),
      dataRoutes: [],
      i18n: config.i18n || undefined,
    }))

    const distDirCreated = await traceAsyncFn(
      tracer.startSpan('create-distdir'),
      async () => {
        try {
          await promises.mkdir(distDir, { recursive: true })
          return true
        } catch (err) {
          if (err.code === 'EPERM') {
            return false
          }
          throw err
        }
      }
    )

    if (!distDirCreated || !(await isWriteable(distDir))) {
      throw new Error(
        '> Build directory is not writeable. https://err.sh/vercel/next.js/build-dir-not-writeable'
      )
    }

    // We need to write the manifest with rewrites before build
    // so serverless can import the manifest
    await traceAsyncFn(tracer.startSpan('write-routes-manifest'), () =>
      promises.writeFile(
        routesManifestPath,
        JSON.stringify(routesManifest),
        'utf8'
      )
    )

    const manifestPath = path.join(
      distDir,
      isLikeServerless ? SERVERLESS_DIRECTORY : SERVER_DIRECTORY,
      PAGES_MANIFEST
    )

    const requiredServerFiles = traceFn(
      tracer.startSpan('generate-required-server-files'),
      () => ({
        version: 1,
        config: {
          ...config,
          compress: false,
          configFile: undefined,
        },
        files: [
          ROUTES_MANIFEST,
          path.relative(distDir, manifestPath),
          BUILD_MANIFEST,
          PRERENDER_MANIFEST,
          REACT_LOADABLE_MANIFEST,
          config.experimental.optimizeFonts
            ? path.join(
                isLikeServerless ? SERVERLESS_DIRECTORY : SERVER_DIRECTORY,
                FONT_MANIFEST
              )
            : null,
          BUILD_ID_FILE,
        ]
          .filter(nonNullable)
          .map((file) => path.join(config.distDir, file)),
        ignore: [
          path.relative(
            dir,
            path.join(path.dirname(require.resolve('sharp')), '**/*')
          ),
        ],
      })
    )

    const configs = await traceAsyncFn(
      tracer.startSpan('generate-webpack-config'),
      () =>
        Promise.all([
          getBaseWebpackConfig(dir, {
            buildId,
            reactProductionProfiling,
            isServer: false,
            config,
            target,
            pagesDir,
            entrypoints: entrypoints.client,
            rewrites,
          }),
          getBaseWebpackConfig(dir, {
            buildId,
            reactProductionProfiling,
            isServer: true,
            config,
            target,
            pagesDir,
            entrypoints: entrypoints.server,
            rewrites,
          }),
        ])
    )

    const clientConfig = configs[0]

    if (
      clientConfig.optimization &&
      (clientConfig.optimization.minimize !== true ||
        (clientConfig.optimization.minimizer &&
          clientConfig.optimization.minimizer.length === 0))
    ) {
      Log.warn(
        `Production code optimization has been disabled in your project. Read more: https://err.sh/vercel/next.js/minification-disabled`
      )
    }

    const webpackBuildStart = process.hrtime()

    let result: CompilerResult = { warnings: [], errors: [] }
    // TODO: why do we need this?? https://github.com/vercel/next.js/issues/8253
    if (isLikeServerless) {
      const clientResult = await runCompiler(clientConfig)
      // Fail build if clientResult contains errors
      if (clientResult.errors.length > 0) {
        result = {
          warnings: [...clientResult.warnings],
          errors: [...clientResult.errors],
        }
      } else {
        const serverResult = await runCompiler(configs[1])
        result = {
          warnings: [...clientResult.warnings, ...serverResult.warnings],
          errors: [...clientResult.errors, ...serverResult.errors],
        }
      }
    } else {
      result = await traceAsyncFn(
        tracer.startSpan('run-webpack-compiler'),
        () => runCompiler(configs)
      )
    }

    const webpackBuildEnd = process.hrtime(webpackBuildStart)
    if (buildSpinner) {
      buildSpinner.stopAndPersist()
    }

    result = traceFn(tracer.startSpan('format-webpack-messages'), () =>
      formatWebpackMessages(result)
    )

    if (result.errors.length > 0) {
      // Only keep the first error. Others are often indicative
      // of the same problem, but confuse the reader with noise.
      if (result.errors.length > 1) {
        result.errors.length = 1
      }
      const error = result.errors.join('\n\n')

      console.error(chalk.red('Failed to compile.\n'))

      if (
        error.indexOf('private-next-pages') > -1 &&
        error.indexOf('does not contain a default export') > -1
      ) {
        const page_name_regex = /'private-next-pages\/(?<page_name>[^']*)'/
        const parsed = page_name_regex.exec(error)
        const page_name = parsed && parsed.groups && parsed.groups.page_name
        throw new Error(
          `webpack build failed: found page without a React Component as default export in pages/${page_name}\n\nSee https://err.sh/vercel/next.js/page-without-valid-component for more info.`
        )
      }

      console.error(error)
      console.error()

      if (
        error.indexOf('private-next-pages') > -1 ||
        error.indexOf('__next_polyfill__') > -1
      ) {
        throw new Error(
          '> webpack config.resolve.alias was incorrectly overridden. https://err.sh/vercel/next.js/invalid-resolve-alias'
        )
      }
      throw new Error('> Build failed because of webpack errors')
    } else {
      telemetry.record(
        eventBuildCompleted(pagePaths, {
          durationInSeconds: webpackBuildEnd[0],
        })
      )

      if (result.warnings.length > 0) {
        Log.warn('Compiled with warnings\n')
        console.warn(result.warnings.join('\n\n'))
        console.warn()
      } else {
        Log.info('Compiled successfully')
      }
    }

    const postCompileSpinner = createSpinner({
      prefixText: `${Log.prefixes.info} Collecting page data`,
    })

    const buildManifestPath = path.join(distDir, BUILD_MANIFEST)

    const ssgPages = new Set<string>()
    const ssgStaticFallbackPages = new Set<string>()
    const ssgBlockingFallbackPages = new Set<string>()
    const staticPages = new Set<string>()
    const invalidPages = new Set<string>()
    const hybridAmpPages = new Set<string>()
    const serverPropsPages = new Set<string>()
    const additionalSsgPaths = new Map<string, Array<string>>()
    const additionalSsgPathsEncoded = new Map<string, Array<string>>()
    const pageInfos = new Map<string, PageInfo>()
    const pagesManifest = JSON.parse(
      await promises.readFile(manifestPath, 'utf8')
    ) as PagesManifest
    const buildManifest = JSON.parse(
      await promises.readFile(buildManifestPath, 'utf8')
    ) as BuildManifest

    let customAppGetInitialProps: boolean | undefined
    let namedExports: Array<string> | undefined
    let isNextImageImported: boolean | undefined
    const analysisBegin = process.hrtime()
    let hasSsrAmpPages = false

    const staticCheckSpan = tracer.startSpan('static-check')
    const { hasNonStaticErrorPage } = await traceAsyncFn(
      staticCheckSpan,
      async () => {
        process.env.NEXT_PHASE = PHASE_PRODUCTION_BUILD

        const staticCheckWorkers = new Worker(staticCheckWorker, {
          numWorkers: config.experimental.cpus,
          enableWorkerThreads: config.experimental.workerThreads,
        }) as Worker & { isPageStatic: typeof isPageStatic }

        staticCheckWorkers.getStdout().pipe(process.stdout)
        staticCheckWorkers.getStderr().pipe(process.stderr)

        const runtimeEnvConfig = {
          publicRuntimeConfig: config.publicRuntimeConfig,
          serverRuntimeConfig: config.serverRuntimeConfig,
        }

        const nonStaticErrorPage = await traceAsyncFn(
          tracer.startSpan('check-static-error-page'),
          async () =>
            hasCustomErrorPage &&
            (await hasCustomGetInitialProps(
              getPagePath('/_error', distDir, isLikeServerless),
              runtimeEnvConfig,
              false
            ))
        )

        await Promise.all(
          pageKeys.map(async (page) => {
            return traceAsyncFn(
              tracer.startSpan('check-page', { attributes: { page } }),
              async () => {
                const actualPage = normalizePagePath(page)
                const [selfSize, allSize] = await getJsPageSizeInKb(
                  actualPage,
                  distDir,
                  buildManifest
                )

                let isSsg = false
                let isStatic = false
                let isHybridAmp = false
                let ssgPageRoutes: string[] | null = null

                const nonReservedPage = !page.match(
                  /^\/(_app|_error|_document|api(\/|$))/
                )

                if (nonReservedPage) {
                  const serverBundle = getPagePath(
                    page,
                    distDir,
                    isLikeServerless
                  )

                  if (customAppGetInitialProps === undefined) {
                    customAppGetInitialProps = await hasCustomGetInitialProps(
                      isLikeServerless
                        ? serverBundle
                        : getPagePath('/_app', distDir, isLikeServerless),
                      runtimeEnvConfig,
                      true
                    )

                    namedExports = getNamedExports(
                      isLikeServerless
                        ? serverBundle
                        : getPagePath('/_app', distDir, isLikeServerless),
                      runtimeEnvConfig
                    )

                    if (customAppGetInitialProps) {
                      console.warn(
                        chalk.bold.yellow(`Warning: `) +
                          chalk.yellow(
                            `You have opted-out of Automatic Static Optimization due to \`getInitialProps\` in \`pages/_app\`. This does not opt-out pages with \`getStaticProps\``
                          )
                      )
                      console.warn(
                        'Read more: https://err.sh/next.js/opt-out-auto-static-optimization\n'
                      )
                    }
                  }

                  try {
                    let workerResult = await traceAsyncFn(
                      tracer.startSpan('is-page-static'),
                      () => {
                        const spanContext = {}

                        opentelemetryApi.propagation.inject(
                          opentelemetryApi.context.active(),
                          spanContext
                        )
                        return staticCheckWorkers.isPageStatic(
                          page,
                          serverBundle,
                          runtimeEnvConfig,
                          config.i18n?.locales,
                          config.i18n?.defaultLocale,
                          spanContext
                        )
                      }
                    )

                    if (
                      workerResult.isStatic === false &&
                      (workerResult.isHybridAmp || workerResult.isAmpOnly)
                    ) {
                      hasSsrAmpPages = true
                    }

                    if (workerResult.isHybridAmp) {
                      isHybridAmp = true
                      hybridAmpPages.add(page)
                    }

                    if (workerResult.isNextImageImported) {
                      isNextImageImported = true
                    }

                    if (workerResult.hasStaticProps) {
                      ssgPages.add(page)
                      isSsg = true

                      if (
                        workerResult.prerenderRoutes &&
                        workerResult.encodedPrerenderRoutes
                      ) {
                        additionalSsgPaths.set(
                          page,
                          workerResult.prerenderRoutes
                        )
                        additionalSsgPathsEncoded.set(
                          page,
                          workerResult.encodedPrerenderRoutes
                        )
                        ssgPageRoutes = workerResult.prerenderRoutes
                      }

                      if (workerResult.prerenderFallback === 'blocking') {
                        ssgBlockingFallbackPages.add(page)
                      } else if (workerResult.prerenderFallback === true) {
                        ssgStaticFallbackPages.add(page)
                      }
                    } else if (workerResult.hasServerProps) {
                      serverPropsPages.add(page)
                    } else if (
                      workerResult.isStatic &&
                      customAppGetInitialProps === false
                    ) {
                      staticPages.add(page)
                      isStatic = true
                    }

                    if (hasPages404 && page === '/404') {
                      if (
                        !workerResult.isStatic &&
                        !workerResult.hasStaticProps
                      ) {
                        throw new Error(PAGES_404_GET_INITIAL_PROPS_ERROR)
                      }
                      // we need to ensure the 404 lambda is present since we use
                      // it when _app has getInitialProps
                      if (
                        customAppGetInitialProps &&
                        !workerResult.hasStaticProps
                      ) {
                        staticPages.delete(page)
                      }
                    }
                  } catch (err) {
                    if (err.message !== 'INVALID_DEFAULT_EXPORT') throw err
                    invalidPages.add(page)
                  }
                }

                pageInfos.set(page, {
                  size: selfSize,
                  totalSize: allSize,
                  static: isStatic,
                  isSsg,
                  isHybridAmp,
                  ssgPageRoutes,
                  initialRevalidateSeconds: false,
                })
              }
            )
          })
        )
        staticCheckWorkers.end()

        return { hasNonStaticErrorPage: nonStaticErrorPage }
      }
    )

    if (!hasSsrAmpPages) {
      requiredServerFiles.ignore.push(
        path.relative(
          dir,
          path.join(
            path.dirname(require.resolve('@ampproject/toolbox-optimizer')),
            '**/*'
          )
        )
      )
    }

    if (serverPropsPages.size > 0 || ssgPages.size > 0) {
      // We update the routes manifest after the build with the
      // data routes since we can't determine these until after build
      routesManifest.dataRoutes = getSortedRoutes([
        ...serverPropsPages,
        ...ssgPages,
      ]).map((page) => {
        const pagePath = normalizePagePath(page)
        const dataRoute = path.posix.join(
          '/_next/data',
          buildId,
          `${pagePath}.json`
        )

        let dataRouteRegex: string
        let namedDataRouteRegex: string | undefined
        let routeKeys: { [named: string]: string } | undefined

        if (isDynamicRoute(page)) {
          const routeRegex = getRouteRegex(dataRoute.replace(/\.json$/, ''))

          dataRouteRegex = normalizeRouteRegex(
            routeRegex.re.source.replace(/\(\?:\\\/\)\?\$$/, '\\.json$')
          )
          namedDataRouteRegex = routeRegex.namedRegex!.replace(
            /\(\?:\/\)\?\$$/,
            '\\.json$'
          )
          routeKeys = routeRegex.routeKeys
        } else {
          dataRouteRegex = normalizeRouteRegex(
            new RegExp(
              `^${path.posix.join(
                '/_next/data',
                escapeStringRegexp(buildId),
                `${pagePath}.json`
              )}$`
            ).source
          )
        }

        return {
          page,
          routeKeys,
          dataRouteRegex,
          namedDataRouteRegex,
        }
      })

      await promises.writeFile(
        routesManifestPath,
        JSON.stringify(routesManifest),
        'utf8'
      )
    }

    // Since custom _app.js can wrap the 404 page we have to opt-out of static optimization if it has getInitialProps
    // Only export the static 404 when there is no /_error present
    const useStatic404 =
      !customAppGetInitialProps && (!hasNonStaticErrorPage || hasPages404)

    if (invalidPages.size > 0) {
      throw new Error(
        `Build optimization failed: found page${
          invalidPages.size === 1 ? '' : 's'
        } without a React Component as default export in \n${[...invalidPages]
          .map((pg) => `pages${pg}`)
          .join(
            '\n'
          )}\n\nSee https://err.sh/vercel/next.js/page-without-valid-component for more info.\n`
      )
    }

    await writeBuildId(distDir, buildId)

    await promises.writeFile(
      path.join(distDir, SERVER_FILES_MANIFEST),
      JSON.stringify(requiredServerFiles),
      'utf8'
    )

    const finalPrerenderRoutes: { [route: string]: SsgRoute } = {}
    const tbdPrerenderRoutes: string[] = []
    let ssgNotFoundPaths: string[] = []

    if (postCompileSpinner) postCompileSpinner.stopAndPersist()

    await traceAsyncFn(tracer.startSpan('static-generation'), async () => {
      if (staticPages.size > 0 || ssgPages.size > 0 || useStatic404) {
        const combinedPages = [...staticPages, ...ssgPages]
        const exportApp = require('../export').default
        const exportOptions = {
          silent: false,
          buildExport: true,
          threads: config.experimental.cpus,
          pages: combinedPages,
          outdir: path.join(distDir, 'export'),
          statusMessage: 'Generating static pages',
        }
        const exportConfig: any = {
          ...config,
          initialPageRevalidationMap: {},
          ssgNotFoundPaths: [] as string[],
          // Default map will be the collection of automatic statically exported
          // pages and incremental pages.
          // n.b. we cannot handle this above in combinedPages because the dynamic
          // page must be in the `pages` array, but not in the mapping.
          exportPathMap: (defaultMap: any) => {
            const { i18n } = config

            // Dynamically routed pages should be prerendered to be used as
            // a client-side skeleton (fallback) while data is being fetched.
            // This ensures the end-user never sees a 500 or slow response from the
            // server.
            //
            // Note: prerendering disables automatic static optimization.
            ssgPages.forEach((page) => {
              if (isDynamicRoute(page)) {
                tbdPrerenderRoutes.push(page)

                if (ssgStaticFallbackPages.has(page)) {
                  // Override the rendering for the dynamic page to be treated as a
                  // fallback render.
                  if (i18n) {
                    defaultMap[`/${i18n.defaultLocale}${page}`] = {
                      page,
                      query: { __nextFallback: true },
                    }
                  } else {
                    defaultMap[page] = { page, query: { __nextFallback: true } }
                  }
                } else {
                  // Remove dynamically routed pages from the default path map when
                  // fallback behavior is disabled.
                  delete defaultMap[page]
                }
              }
            })
            // Append the "well-known" routes we should prerender for, e.g. blog
            // post slugs.
            additionalSsgPaths.forEach((routes, page) => {
              const encodedRoutes = additionalSsgPathsEncoded.get(page)

              routes.forEach((route, routeIdx) => {
                defaultMap[route] = {
                  page,
                  query: { __nextSsgPath: encodedRoutes?.[routeIdx] },
                }
              })
            })

            if (useStatic404) {
              defaultMap['/404'] = {
                page: hasPages404 ? '/404' : '/_error',
              }
            }

            if (i18n) {
              for (const page of [
                ...staticPages,
                ...ssgPages,
                ...(useStatic404 ? ['/404'] : []),
              ]) {
                const isSsg = ssgPages.has(page)
                const isDynamic = isDynamicRoute(page)
                const isFallback = isSsg && ssgStaticFallbackPages.has(page)

                for (const locale of i18n.locales) {
                  // skip fallback generation for SSG pages without fallback mode
                  if (isSsg && isDynamic && !isFallback) continue
                  const outputPath = `/${locale}${page === '/' ? '' : page}`

                  defaultMap[outputPath] = {
                    page: defaultMap[page]?.page || page,
                    query: { __nextLocale: locale },
                  }

                  if (isFallback) {
                    defaultMap[outputPath].query.__nextFallback = true
                  }
                }

                if (isSsg) {
                  // remove non-locale prefixed variant from defaultMap
                  delete defaultMap[page]
                }
              }
            }

            return defaultMap
          },
          trailingSlash: false,
        }

        await exportApp(dir, exportOptions, exportConfig)

        const postBuildSpinner = createSpinner({
          prefixText: `${Log.prefixes.info} Finalizing page optimization`,
        })
        ssgNotFoundPaths = exportConfig.ssgNotFoundPaths

        // remove server bundles that were exported
        for (const page of staticPages) {
          const serverBundle = getPagePath(page, distDir, isLikeServerless)
          await promises.unlink(serverBundle)
        }
        const serverOutputDir = path.join(
          distDir,
          isLikeServerless ? SERVERLESS_DIRECTORY : SERVER_DIRECTORY
        )

        const moveExportedPage = async (
          originPage: string,
          page: string,
          file: string,
          isSsg: boolean,
          ext: 'html' | 'json',
          additionalSsgFile = false
        ) => {
          return traceAsyncFn(
            tracer.startSpan('move-exported-page'),
            async () => {
              file = `${file}.${ext}`
              const orig = path.join(exportOptions.outdir, file)
              const pagePath = getPagePath(
                originPage,
                distDir,
                isLikeServerless
              )

              const relativeDest = path
                .relative(
                  serverOutputDir,
                  path.join(
                    path.join(
                      pagePath,
                      // strip leading / and then recurse number of nested dirs
                      // to place from base folder
                      originPage
                        .substr(1)
                        .split('/')
                        .map(() => '..')
                        .join('/')
                    ),
                    file
                  )
                )
                .replace(/\\/g, '/')

              const dest = path.join(
                distDir,
                isLikeServerless ? SERVERLESS_DIRECTORY : SERVER_DIRECTORY,
                relativeDest
              )

              if (!isSsg) {
                pagesManifest[page] = relativeDest
              }

              const { i18n } = config
              const isNotFound = ssgNotFoundPaths.includes(page)

              // for SSG files with i18n the non-prerendered variants are
              // output with the locale prefixed so don't attempt moving
              // without the prefix
              if ((!i18n || additionalSsgFile) && !isNotFound) {
                await promises.mkdir(path.dirname(dest), { recursive: true })
                await promises.rename(orig, dest)
              } else if (i18n && !isSsg) {
                // this will be updated with the locale prefixed variant
                // since all files are output with the locale prefix
                delete pagesManifest[page]
              }

              if (i18n) {
                if (additionalSsgFile) return

                for (const locale of i18n.locales) {
                  const curPath = `/${locale}${page === '/' ? '' : page}`
                  const localeExt = page === '/' ? path.extname(file) : ''
                  const relativeDestNoPages = relativeDest.substr(
                    'pages/'.length
                  )

                  if (isSsg && ssgNotFoundPaths.includes(curPath)) {
                    continue
                  }

                  const updatedRelativeDest = path
                    .join(
                      'pages',
                      locale + localeExt,
                      // if it's the top-most index page we want it to be locale.EXT
                      // instead of locale/index.html
                      page === '/' ? '' : relativeDestNoPages
                    )
                    .replace(/\\/g, '/')

                  const updatedOrig = path.join(
                    exportOptions.outdir,
                    locale + localeExt,
                    page === '/' ? '' : file
                  )
                  const updatedDest = path.join(
                    distDir,
                    isLikeServerless ? SERVERLESS_DIRECTORY : SERVER_DIRECTORY,
                    updatedRelativeDest
                  )

                  if (!isSsg) {
                    pagesManifest[curPath] = updatedRelativeDest
                  }
                  await promises.mkdir(path.dirname(updatedDest), {
                    recursive: true,
                  })
                  await promises.rename(updatedOrig, updatedDest)
                }
              }
            }
          )
        }

        // Only move /404 to /404 when there is no custom 404 as in that case we don't know about the 404 page
        if (!hasPages404 && useStatic404) {
          await moveExportedPage('/_error', '/404', '/404', false, 'html')
        }

        for (const page of combinedPages) {
          const isSsg = ssgPages.has(page)
          const isStaticSsgFallback = ssgStaticFallbackPages.has(page)
          const isDynamic = isDynamicRoute(page)
          const hasAmp = hybridAmpPages.has(page)
          const file = normalizePagePath(page)

          // The dynamic version of SSG pages are only prerendered if the fallback
          // is enabled. Below, we handle the specific prerenders of these.
          if (!(isSsg && isDynamic && !isStaticSsgFallback)) {
            await moveExportedPage(page, page, file, isSsg, 'html')
          }

          if (hasAmp && (!isSsg || (isSsg && !isDynamic))) {
            const ampPage = `${file}.amp`
            await moveExportedPage(page, ampPage, ampPage, isSsg, 'html')

            if (isSsg) {
              await moveExportedPage(page, ampPage, ampPage, isSsg, 'json')
            }
          }

          if (isSsg) {
            const { i18n } = config

            // For a non-dynamic SSG page, we must copy its data file from export.
            if (!isDynamic) {
              await moveExportedPage(page, page, file, true, 'json')

              const revalidationMapPath = i18n
                ? `/${i18n.defaultLocale}${page === '/' ? '' : page}`
                : page

              finalPrerenderRoutes[page] = {
                initialRevalidateSeconds:
                  exportConfig.initialPageRevalidationMap[revalidationMapPath],
                srcRoute: null,
                dataRoute: path.posix.join(
                  '/_next/data',
                  buildId,
                  `${file}.json`
                ),
              }
              // Set Page Revalidation Interval
              const pageInfo = pageInfos.get(page)
              if (pageInfo) {
                pageInfo.initialRevalidateSeconds =
                  exportConfig.initialPageRevalidationMap[revalidationMapPath]
                pageInfos.set(page, pageInfo)
              }
            } else {
              // For a dynamic SSG page, we did not copy its data exports and only
              // copy the fallback HTML file (if present).
              // We must also copy specific versions of this page as defined by
              // `getStaticPaths` (additionalSsgPaths).
              const extraRoutes = additionalSsgPaths.get(page) || []
              for (const route of extraRoutes) {
                const pageFile = normalizePagePath(route)
                await moveExportedPage(
                  page,
                  route,
                  pageFile,
                  true,
                  'html',
                  true
                )
                await moveExportedPage(
                  page,
                  route,
                  pageFile,
                  true,
                  'json',
                  true
                )

                if (hasAmp) {
                  const ampPage = `${pageFile}.amp`
                  await moveExportedPage(
                    page,
                    ampPage,
                    ampPage,
                    true,
                    'html',
                    true
                  )
                  await moveExportedPage(
                    page,
                    ampPage,
                    ampPage,
                    true,
                    'json',
                    true
                  )
                }

                finalPrerenderRoutes[route] = {
                  initialRevalidateSeconds:
                    exportConfig.initialPageRevalidationMap[route],
                  srcRoute: page,
                  dataRoute: path.posix.join(
                    '/_next/data',
                    buildId,
                    `${normalizePagePath(route)}.json`
                  ),
                }

                // Set route Revalidation Interval
                const pageInfo = pageInfos.get(route)
                if (pageInfo) {
                  pageInfo.initialRevalidateSeconds =
                    exportConfig.initialPageRevalidationMap[route]
                  pageInfos.set(route, pageInfo)
                }
              }
            }
          }
        }

        // remove temporary export folder
        await recursiveDelete(exportOptions.outdir)
        await promises.rmdir(exportOptions.outdir)
        await promises.writeFile(
          manifestPath,
          JSON.stringify(pagesManifest, null, 2),
          'utf8'
        )

        if (postBuildSpinner) postBuildSpinner.stopAndPersist()
        console.log()
      }
    })

    const analysisEnd = process.hrtime(analysisBegin)
    telemetry.record(
      eventBuildOptimize(pagePaths, {
        durationInSeconds: analysisEnd[0],
        staticPageCount: staticPages.size,
        staticPropsPageCount: ssgPages.size,
        serverPropsPageCount: serverPropsPages.size,
        ssrPageCount:
          pagePaths.length -
          (staticPages.size + ssgPages.size + serverPropsPages.size),
        hasStatic404: useStatic404,
        hasReportWebVitals: namedExports?.includes('reportWebVitals') ?? false,
        rewritesCount: rewrites.length,
        headersCount: headers.length,
        redirectsCount: redirects.length - 1, // reduce one for trailing slash
      })
    )

    if (ssgPages.size > 0) {
      const finalDynamicRoutes: PrerenderManifest['dynamicRoutes'] = {}
      tbdPrerenderRoutes.forEach((tbdRoute) => {
        const normalizedRoute = normalizePagePath(tbdRoute)
        const dataRoute = path.posix.join(
          '/_next/data',
          buildId,
          `${normalizedRoute}.json`
        )

        finalDynamicRoutes[tbdRoute] = {
          routeRegex: normalizeRouteRegex(getRouteRegex(tbdRoute).re.source),
          dataRoute,
          fallback: ssgBlockingFallbackPages.has(tbdRoute)
            ? null
            : ssgStaticFallbackPages.has(tbdRoute)
            ? `${normalizedRoute}.html`
            : false,
          dataRouteRegex: normalizeRouteRegex(
            getRouteRegex(dataRoute.replace(/\.json$/, '')).re.source.replace(
              /\(\?:\\\/\)\?\$$/,
              '\\.json$'
            )
          ),
        }
      })
      const prerenderManifest: PrerenderManifest = {
        version: 2,
        routes: finalPrerenderRoutes,
        dynamicRoutes: finalDynamicRoutes,
        notFoundRoutes: ssgNotFoundPaths,
        preview: previewProps,
      }

      await promises.writeFile(
        path.join(distDir, PRERENDER_MANIFEST),
        JSON.stringify(prerenderManifest),
        'utf8'
      )
      await generateClientSsgManifest(prerenderManifest, {
        distDir,
        buildId,
      })
    } else {
      const prerenderManifest: PrerenderManifest = {
        version: 2,
        routes: {},
        dynamicRoutes: {},
        preview: previewProps,
        notFoundRoutes: [],
      }
      await promises.writeFile(
        path.join(distDir, PRERENDER_MANIFEST),
        JSON.stringify(prerenderManifest),
        'utf8'
      )
    }

    const images = { ...config.images }
    const { deviceSizes, imageSizes } = images
    images.sizes = [...deviceSizes, ...imageSizes]

    await promises.writeFile(
      path.join(distDir, IMAGES_MANIFEST),
      JSON.stringify({
        version: 1,
        images,
      }),
      'utf8'
    )

    await promises.writeFile(
      path.join(distDir, EXPORT_MARKER),
      JSON.stringify({
        version: 1,
        hasExportPathMap: typeof config.exportPathMap === 'function',
        exportTrailingSlash: config.trailingSlash === true,
        isNextImageImported: isNextImageImported === true,
      }),
      'utf8'
    )
    await promises.unlink(path.join(distDir, EXPORT_DETAIL)).catch((err) => {
      if (err.code === 'ENOENT') {
        return Promise.resolve()
      }
      return Promise.reject(err)
    })

    staticPages.forEach((pg) => allStaticPages.add(pg))
    pageInfos.forEach((info: PageInfo, key: string) => {
      allPageInfos.set(key, info)
    })

    await traceAsyncFn(tracer.startSpan('print-tree-view'), () =>
      printTreeView(Object.keys(mappedPages), allPageInfos, isLikeServerless, {
        distPath: distDir,
        buildId: buildId,
        pagesDir,
        useStatic404,
        pageExtensions: config.pageExtensions,
        buildManifest,
      })
    )

    if (debugOutput) {
      traceFn(tracer.startSpan('print-custom-routes'), () =>
        printCustomRoutes({ redirects, rewrites, headers })
      )
    }

    if (config.analyticsId) {
      console.log(
        chalk.bold.green('Next.js Analytics') +
          ' is enabled for this production build. ' +
          "You'll receive a Real Experience Score computed by all of your visitors."
      )
      console.log('')
    }

    await traceAsyncFn(tracer.startSpan('telemetry-flush'), () =>
      telemetry.flush()
    )
  })
}

export type ClientSsgManifest = Set<string>

function generateClientSsgManifest(
  prerenderManifest: PrerenderManifest,
  { buildId, distDir }: { buildId: string; distDir: string }
) {
  const ssgPages: ClientSsgManifest = new Set<string>([
    ...Object.entries(prerenderManifest.routes)
      // Filter out dynamic routes
      .filter(([, { srcRoute }]) => srcRoute == null)
      .map(([route]) => route),
    ...Object.keys(prerenderManifest.dynamicRoutes),
  ])

  const clientSsgManifestContent = `self.__SSG_MANIFEST=${devalue(
    ssgPages
  )};self.__SSG_MANIFEST_CB&&self.__SSG_MANIFEST_CB()`

  writeFileSync(
    path.join(distDir, CLIENT_STATIC_FILES_PATH, buildId, '_ssgManifest.js'),
    clientSsgManifestContent
  )
}