[lint] Disable linting using project config for tests (#66145)

During integration testing, previously, calls to `next build` could rely
on the project (the Next.js project) level ESLint configuration. In
order to correct this, a new `lint` option was added to `nextBuild` that
can be passed to enabled linting. If this is `false` or `undefined`, a
`--no-lint` argument will be passed to `next build` to prevent it from
running.

test/integration/clean-distdir/test/index.test.js

@@ -5,17 +5,18 @@ import { join } from 'path'
 import { nextBuild } from 'next-test-utils'
 
 const appDir = join(__dirname, '../')
-const customFile = join(appDir, '.next/extra-file.txt')
-const cacheDir = join(appDir, '.next/cache')
-// const swcCacheDir = join(appDir, '.next/cache/swc')
+const nextDir = join(appDir, '.next')
+const customFile = join(nextDir, '/extra-file.txt')
+const cacheDir = join(nextDir, '/cache')
+// const swcCacheDir = join(nextDir, '/cache/swc')
 const nextConfig = join(appDir, 'next.config.js')
 
 let nextConfigContent
 
 async function checkFileWrite(existsAfterBuild) {
-  await nextBuild(appDir)
+  await nextBuild(appDir, [], { lint: true })
   fs.writeFileSync(customFile, 'this is a testing file')
-  await nextBuild(appDir)
+  await nextBuild(appDir, [], { lint: true })
   expect(fs.existsSync(customFile)).toBe(existsAfterBuild)
   // `.next/cache` should be preserved in all cases
   expect(fs.existsSync(cacheDir)).toBe(true)
@@ -32,6 +33,10 @@ describe('Cleaning distDir', () => {
   ;(process.env.TURBOPACK_DEV ? describe.skip : describe)(
     'production mode',
     () => {
+      beforeAll(() => {
+        fs.removeSync(nextDir)
+      })
+
       runTests()
 
       describe('disabled write', () => {

test/integration/dist-dir/test/index.test.js

@@ -25,7 +25,7 @@ describe('distDir', () => {
         beforeAll(async () => {
           await fs.remove(join(appDir, '.next'))
           await fs.remove(join(appDir, 'dist'))
-          await nextBuild(appDir)
+          await nextBuild(appDir, [], { lint: true })
           appPort = await findPort()
           app = await nextStart(appDir, appPort)
         })
@@ -79,7 +79,10 @@ describe('distDir', () => {
       it('should throw error with invalid distDir', async () => {
         const origNextConfig = await fs.readFile(nextConfig, 'utf8')
         await fs.writeFile(nextConfig, `module.exports = { distDir: '' }`)
-        const { stderr } = await nextBuild(appDir, [], { stderr: true })
+        const { stderr } = await nextBuild(appDir, [], {
+          stderr: true,
+          lint: true,
+        })
         await fs.writeFile(nextConfig, origNextConfig)
 
         expect(stderr).toContain(
@@ -93,7 +96,10 @@ describe('distDir', () => {
           nextConfig,
           `module.exports = { distDir: undefined, eslint: { ignoreDuringBuilds: true } }`
         )
-        const { stderr } = await nextBuild(appDir, [], { stderr: true })
+        const { stderr } = await nextBuild(appDir, [], {
+          stderr: true,
+          lint: true,
+        })
         await fs.writeFile(nextConfig, origNextConfig)
 
         expect(stderr.length).toBe(0)

test/integration/eslint/test/lint-cache.test.js

@@ -1,43 +1,11 @@
 import fs from 'fs-extra'
-import os from 'os'
 
 import { join } from 'path'
 
-import findUp from 'next/dist/compiled/find-up'
-import { File, nextBuild, nextLint } from 'next-test-utils'
+import { nextLint } from 'next-test-utils'
 
-const dirFirstTimeSetup = join(__dirname, '../first-time-setup')
-const dirCustomConfig = join(__dirname, '../custom-config')
-const dirWebVitalsConfig = join(__dirname, '../config-core-web-vitals')
-const dirPluginRecommendedConfig = join(
-  __dirname,
-  '../plugin-recommended-config'
-)
-const dirPluginCoreWebVitalsConfig = join(
-  __dirname,
-  '../plugin-core-web-vitals-config'
-)
-const dirIgnoreDuringBuilds = join(__dirname, '../ignore-during-builds')
-const dirBaseDirectories = join(__dirname, '../base-directories')
-const dirBaseDirectoriesConfigFile = new File(
-  join(dirBaseDirectories, '/next.config.js')
-)
-const dirCustomDirectories = join(__dirname, '../custom-directories')
-const dirConfigInPackageJson = join(__dirname, '../config-in-package-json')
-const dirInvalidOlderEslintVersion = join(
-  __dirname,
-  '../invalid-eslint-version'
-)
-const dirMaxWarnings = join(__dirname, '../max-warnings')
-const dirEmptyDirectory = join(__dirname, '../empty-directory')
-const dirEslintIgnore = join(__dirname, '../eslint-ignore')
-const dirNoEslintPlugin = join(__dirname, '../no-eslint-plugin')
-const dirNoConfig = join(__dirname, '../no-config')
 const dirEslintCache = join(__dirname, '../eslint-cache')
 const dirEslintCacheCustomDir = join(__dirname, '../eslint-cache-custom-dir')
-const dirFileLinting = join(__dirname, '../file-linting')
-const mjsCjsLinting = join(__dirname, '../mjs-cjs-linting')
-const dirTypescript = join(__dirname, '../with-typescript')
 
 test('eslint caching is enabled by default', async () => {
   const cacheDir = join(dirEslintCache, '.next', 'cache')

test/integration/eslint/test/next-build.test.js

@@ -1,43 +1,23 @@
 import fs from 'fs-extra'
-import os from 'os'
 
 import { join } from 'path'
 
-import findUp from 'next/dist/compiled/find-up'
-import { File, nextBuild, nextLint } from 'next-test-utils'
+import { nextBuild } from 'next-test-utils'
 
 const dirFirstTimeSetup = join(__dirname, '../first-time-setup')
 const dirCustomConfig = join(__dirname, '../custom-config')
-const dirWebVitalsConfig = join(__dirname, '../config-core-web-vitals')
-const dirPluginRecommendedConfig = join(
-  __dirname,
-  '../plugin-recommended-config'
-)
-const dirPluginCoreWebVitalsConfig = join(
-  __dirname,
-  '../plugin-core-web-vitals-config'
-)
 const dirIgnoreDuringBuilds = join(__dirname, '../ignore-during-builds')
 const dirBaseDirectories = join(__dirname, '../base-directories')
-const dirBaseDirectoriesConfigFile = new File(
-  join(dirBaseDirectories, '/next.config.js')
-)
 const dirCustomDirectories = join(__dirname, '../custom-directories')
-const dirConfigInPackageJson = join(__dirname, '../config-in-package-json')
 const dirInvalidOlderEslintVersion = join(
   __dirname,
   '../invalid-eslint-version'
 )
-const dirMaxWarnings = join(__dirname, '../max-warnings')
 const dirEmptyDirectory = join(__dirname, '../empty-directory')
 const dirEslintIgnore = join(__dirname, '../eslint-ignore')
 const dirNoEslintPlugin = join(__dirname, '../no-eslint-plugin')
-const dirNoConfig = join(__dirname, '../no-config')
 const dirEslintCache = join(__dirname, '../eslint-cache')
 const dirEslintCacheCustomDir = join(__dirname, '../eslint-cache-custom-dir')
-const dirFileLinting = join(__dirname, '../file-linting')
-const mjsCjsLinting = join(__dirname, '../mjs-cjs-linting')
-const dirTypescript = join(__dirname, '../with-typescript')
 
 describe('Next Build', () => {
   ;(process.env.TURBOPACK_DEV ? describe.skip : describe)(
@@ -50,6 +30,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirFirstTimeSetup, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
         const output = stdout + stderr
 
@@ -62,6 +43,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirCustomConfig, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -77,6 +59,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirIgnoreDuringBuilds, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -90,6 +73,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirBaseDirectories, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -121,6 +105,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirCustomDirectories, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -140,6 +125,7 @@ describe('Next Build', () => {
           {
             stdout: true,
             stderr: true,
+            lint: true,
           }
         )
 
@@ -153,6 +139,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirEmptyDirectory, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -168,6 +155,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirEslintIgnore, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -183,6 +171,7 @@ describe('Next Build', () => {
         const { stdout, stderr } = await nextBuild(dirNoEslintPlugin, [], {
           stdout: true,
           stderr: true,
+          lint: true,
         })
 
         const output = stdout + stderr
@@ -195,7 +184,9 @@ describe('Next Build', () => {
         const cacheDir = join(dirEslintCache, '.next', 'cache')
 
         await fs.remove(cacheDir)
-        await nextBuild(dirEslintCache, [])
+        await nextBuild(dirEslintCache, [], {
+          lint: true,
+        })
 
         const files = await fs.readdir(join(cacheDir, 'eslint/'))
         const cacheExists = files.some((f) => /\.cache/.test(f))
@@ -210,7 +201,9 @@ describe('Next Build', () => {
         await fs.remove(oldCacheDir)
         await fs.remove(newCacheDir)
 
-        await nextBuild(dirEslintCacheCustomDir, [])
+        await nextBuild(dirEslintCacheCustomDir, [], {
+          lint: true,
+        })
 
         expect(fs.existsSync(oldCacheDir)).toBe(false)
 

test/integration/telemetry/test/config.test.js

@@ -165,6 +165,7 @@ describe('config telemetry', () => {
         const { stderr } = await nextBuild(appDir, [], {
           stderr: true,
           env: { NEXT_TELEMETRY_DEBUG: 1 },
+          lint: true,
         })
         await fs.remove(path.join(appDir, '.eslintrc'))
 
@@ -222,6 +223,7 @@ describe('config telemetry', () => {
         const { stderr } = await nextBuild(appDir, [], {
           stderr: true,
           env: { NEXT_TELEMETRY_DEBUG: 1 },
+          lint: true,
         })
         await fs.remove(nextConfig)
 
@@ -266,6 +268,7 @@ describe('config telemetry', () => {
         const { stderr } = await nextBuild(appDir, [], {
           stderr: true,
           env: { NEXT_TELEMETRY_DEBUG: 1 },
+          lint: true,
         })
         const featureUsageEvents = findAllTelemetryEvents(
           stderr,

test/lib/next-modes/next-start.ts

@@ -68,6 +68,7 @@ export class NextStartInstance extends NextInstance {
     if (this.buildCommand) {
       buildArgs = this.buildCommand.split(' ')
     }
+
     if (this.startCommand) {
       startArgs = this.startCommand.split(' ')
     }

test/lib/next-test-utils.ts

@@ -192,6 +192,12 @@ export interface NextOptions {
   stdout?: true | 'log'
   ignoreFail?: boolean
 
+  /**
+   * If true, this enables the linting step in the build process. If false or
+   * undefined, it adds a `--no-lint` flag to the build command.
+   */
+  lint?: boolean
+
   onStdout?: (data: any) => void
   onStderr?: (data: any) => void
 }
@@ -442,6 +448,12 @@ export function nextBuild(
   args: string[] = [],
   opts: NextOptions = {}
 ) {
+  // If the build hasn't requested it to be linted explicitly, disable linting
+  // if it's not already disabled.
+  if (!opts.lint && !args.includes('--no-lint')) {
+    args.push('--no-lint')
+  }
+
   return runNextCommand(['build', dir, ...args], opts)
 }