Update checking for existing dotenv usage

packages/next/lib/load-env-config.ts

@@ -1,28 +1,49 @@
 import fs from 'fs'
 import path from 'path'
 import chalk from 'next/dist/compiled/chalk'
+import findUp from 'next/dist/compiled/find-up'
 import dotenvExpand from 'next/dist/compiled/dotenv-expand'
 import dotenv, { DotenvConfigOutput } from 'next/dist/compiled/dotenv'
-import findUp from 'next/dist/compiled/find-up'
 
 export type Env = { [key: string]: string }
 
+const packageJsonHasDep = (packageJsonPath: string, dep: string): boolean => {
+  const { dependencies, devDependencies } = require(packageJsonPath)
+  const allPackages = Object.keys({
+    ...dependencies,
+    ...devDependencies,
+  })
+
+  return allPackages.some(pkg => pkg === dep)
+}
+
 export function loadEnvConfig(dir: string, dev?: boolean): Env | false {
   const packageJson = findUp.sync('package.json', { cwd: dir })
 
   // only do new env loading if dotenv isn't installed since we
   // can't check for an experimental flag in next.config.js
   // since we want to load the env before loading next.config.js
   if (packageJson) {
-    const { dependencies, devDependencies } = require(packageJson)
-    const allPackages = Object.keys({
-      ...dependencies,
-      ...devDependencies,
-    })
-
-    if (allPackages.some(pkg => pkg === 'dotenv')) {
+    // check main `package.json` first
+    if (packageJsonHasDep(packageJson, 'dotenv')) {
       return false
     }
+    // check for a yarn.lock or lerna.json file in case it's a monorepo
+    const monorepoFile = findUp.sync(
+      ['yarn.lock', 'lerna.json', 'package-lock.json'],
+      { cwd: dir }
+    )
+
+    if (monorepoFile) {
+      const monorepoRoot = path.dirname(monorepoFile)
+      const monorepoPackageJson = path.join(monorepoRoot, 'package.json')
+
+      try {
+        if (packageJsonHasDep(monorepoPackageJson, 'dotenv')) {
+          return false
+        }
+      } catch (_) {}
+    }
   } else {
     // we should always have a package.json but disable in case we don't
     return false
@@ -49,6 +70,13 @@ export function loadEnvConfig(dir: string, dev?: boolean): Env | false {
     const dotEnvPath = path.join(dir, envFile)
 
     try {
+      const stats = fs.statSync(dotEnvPath)
+
+      // make sure to only attempt to read files
+      if (!stats.isFile()) {
+        continue
+      }
+
       const contents = fs.readFileSync(dotEnvPath, 'utf8')
       let result: DotenvConfigOutput = {}
       result.parsed = dotenv.parse(contents)
@@ -62,7 +90,7 @@ export function loadEnvConfig(dir: string, dev?: boolean): Env | false {
       Object.assign(combinedEnv, result.parsed)
     } catch (err) {
       if (err.code !== 'ENOENT') {
-        console.log(
+        console.error(
           `> ${chalk.cyan.bold('Error: ')} Failed to load env from ${envFile}`,
           err
         )

test/integration/env-config-disable/app/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "env-config",
+  "devDependencies": {
+    "dotenv": "latest"
+  }
+}

test/integration/env-config-disable/app/packages/sub-app/.env/.env.development

@@ -0,0 +1 @@
+HELLO=world

test/integration/env-config-disable/app/packages/sub-app/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "env-config",
+  "dependencies": {}
+}

test/integration/env-config-disable/app/packages/sub-app/pages/index.js

@@ -0,0 +1 @@
+export default () => 'hi'

test/integration/env-config-disable/test/index.test.js

@@ -0,0 +1,82 @@
+/* eslint-env jest */
+/* global jasmine */
+import fs from 'fs-extra'
+import { join } from 'path'
+import {
+  nextBuild,
+  findPort,
+  launchApp,
+  killApp,
+  nextStart,
+  renderViaHTTP,
+} from 'next-test-utils'
+
+jasmine.DEFAULT_TIMEOUT_INTERVAL = 1000 * 60 * 2
+
+const monorepoRoot = join(__dirname, '../app')
+const yarnLock = join(monorepoRoot, 'yarn.lock')
+const lernaConf = join(monorepoRoot, 'lerna.json')
+const appDir = join(monorepoRoot, 'packages/sub-app')
+
+let app
+let appPort
+
+const runTests = () => {
+  describe('dev mode', () => {
+    it('should start dev server without errors', async () => {
+      let stderr = ''
+      appPort = await findPort()
+      app = await launchApp(appDir, appPort, {
+        onStderr(msg) {
+          stderr += msg || ''
+        },
+      })
+
+      const html = await renderViaHTTP(appPort, '/')
+      await killApp(app)
+
+      expect(html).toContain('hi')
+      expect(stderr).not.toContain('Failed to load env')
+    })
+  })
+
+  describe('production mode', () => {
+    it('should build app successfully', async () => {
+      const { stderr, code } = await nextBuild(appDir, [], { stderr: true })
+      expect(code).toBe(0)
+      expect((stderr || '').length).toBe(0)
+    })
+
+    it('should start without error', async () => {
+      let stderr = ''
+      appPort = await findPort()
+      app = await nextStart(appDir, appPort, {
+        onStderr(msg) {
+          stderr += msg || ''
+        },
+      })
+
+      const html = await renderViaHTTP(appPort, '/')
+      await killApp(app)
+
+      expect(html).toContain('hi')
+      expect(stderr).not.toContain('Failed to load env')
+    })
+  })
+}
+
+describe('Env support disabling', () => {
+  describe('with yarn based monorepo', () => {
+    beforeAll(() => fs.writeFile(yarnLock, 'test'))
+    afterAll(() => fs.remove(yarnLock))
+
+    runTests()
+  })
+
+  describe('with lerna based monorepo', () => {
+    beforeAll(() => fs.writeFile(lernaConf, 'test'))
+    afterAll(() => fs.remove(lernaConf))
+
+    runTests()
+  })
+})