Temporarily remove experimental ESLint integration (vercel#23521)

This pull request **temporarily** removes ESLint, as it was not landed in accordance with our standard experimental policies. We are fully committed to landing this change again.

This is being reverted because:

- Next.js has very strict goals for its install size. This feature resulted in adding over 17MB, or a 43.6% increase.
- The feature was not first landed under the `experimental` key in `next.config.js`, rather, it was added under the stable namespace (top-level)
- Using the feature doesn't do a "guided setup" like TypeScript, it should ask you to "bring your own" dependencies for ESLint
- It uses a undesirable ESLint plugin name: `plugin:@next/next/recommended`. This should read out as strictly `next`, or as short as we can get it.
- Does not provide actionable warnings (missing link to resolve issue)
- Does not follow appropriate console output styling. We need to revisit how these are presented.

To re-land this, we need to ensure the following minimums are met:
- Very minor change in install size
- Fully experimental (i.e. flagged) with warnings
- Finalized package name and configuration shape, preferably so we can do ` { extends: 'next' } `.

.eslintignore

@@ -2,7 +2,6 @@ node_modules
 **/.next/**
 **/_next/**
 **/dist/**
-e2e-tests/**
 examples/with-typescript-eslint-jest/**
 examples/with-kea/**
 packages/next/bundles/webpack/packages/*.runtime.js
@@ -17,5 +16,4 @@ packages/next-codemod/**/*.js
 packages/next-codemod/**/*.d.ts
 packages/next-env/**/*.d.ts
 test/integration/async-modules/**
-test/integration/eslint/**
 test-timings.json

docs/manifest.json

@@ -33,10 +33,6 @@
               "title": "Fast Refresh",
               "path": "/docs/basic-features/fast-refresh.md"
             },
-            {
-              "title": "ESLint",
-              "path": "/docs/basic-features/eslint.md"
-            },
             {
               "title": "TypeScript",
               "path": "/docs/basic-features/typescript.md"
@@ -340,10 +336,6 @@
               "title": "Configuring onDemandEntries",
               "path": "/docs/api-reference/next.config.js/configuring-onDemandEntries.md"
             },
-            {
-              "title": "ESLint Warnings and Errors",
-              "path": "/docs/api-reference/next.config.js/eslint-warnings-errors.md"
-            },
             {
               "title": "Ignoring TypeScript Errors",
               "path": "/docs/api-reference/next.config.js/ignoring-typescript-errors.md"

packages/eslint-plugin-next/lib/rules/no-html-link-for-pages.js

@@ -1,18 +1,10 @@
 const path = require('path')
 const fs = require('fs')
-const {
-  getUrlFromPagesDirectory,
-  normalizeURL,
-  execOnce,
-} = require('../utils/url')
-
-const pagesDirWarning = execOnce((pagesDirs) => {
-  console.warn(
-    `Pages directory cannot be found at ${pagesDirs.join(' or ')}. ` +
-      `If using a custom path, please configure with the no-html-link-for-pages rule in your eslint config file`
-  )
-})
+const { getUrlFromPagesDirectory, normalizeURL } = require('../utils/url')
 
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
 module.exports = {
   meta: {
     docs: {
@@ -34,8 +26,10 @@ module.exports = {
         ]
     const pagesDir = pagesDirs.find((dir) => fs.existsSync(dir))
     if (!pagesDir) {
-      pagesDirWarning(pagesDirs)
-      return {}
+      throw new Error(
+        `Pages directory cannot be found at ${pagesDirs.join(' or ')}. ` +
+          `If using a custom path, please configure with the no-html-link-for-pages rule`
+      )
     }
 
     const urls = getUrlFromPagesDirectory('/', pagesDir)

packages/eslint-plugin-next/lib/utils/url.js

@@ -76,21 +76,7 @@ function normalizeURL(url) {
   return url
 }
 
-function execOnce(fn) {
-  let used = false
-  let result
-
-  return (...args) => {
-    if (!used) {
-      used = true
-      result = fn(...args)
-    }
-    return result
-  }
-}
-
 module.exports = {
   getUrlFromPagesDirectory,
   normalizeURL,
-  execOnce,
 }

packages/next/build/index.ts

@@ -180,41 +180,6 @@ export default async function build(
       telemetry.record(events)
     )
 
-    if (config.eslint?.build) {
-      await nextBuildSpan
-        .traceChild('verify-and-lint')
-        .traceAsyncFn(async () => {
-          const lintWorkers = new Worker(
-            require.resolve('../lib/verifyAndLint'),
-            {
-              numWorkers: config.experimental.cpus,
-              enableWorkerThreads: config.experimental.workerThreads,
-            }
-          ) as Worker & {
-            verifyAndLint: typeof import('../lib/verifyAndLint').verifyAndLint
-          }
-
-          lintWorkers.getStdout().pipe(process.stdout)
-          lintWorkers.getStderr().pipe(process.stderr)
-
-          const lintResults = await lintWorkers.verifyAndLint(
-            dir,
-            pagesDir,
-            null
-          )
-
-          if (lintResults.hasErrors) {
-            console.error(chalk.red('Failed to compile.'))
-            console.error(lintResults.results)
-            process.exit(1)
-          } else if (lintResults.hasMessages) {
-            console.log(lintResults.results)
-          }
-
-          lintWorkers.end()
-        })
-    }
-
     const ignoreTypeScriptErrors = Boolean(config.typescript?.ignoreBuildErrors)
     await nextBuildSpan
       .traceChild('verify-typescript-setup')