feat: add Nx config checks

Author: ascorbic

helpers/checkNxConfig.js

@@ -0,0 +1,50 @@
+const { existsSync } = require('fs')
+const { EOL } = require('os')
+const path = require('path')
+
+const checkNxConfig = ({ netlifyConfig, nextConfig, failBuild, constants: { PUBLISH_DIR } }) => {
+  const errors = []
+  if (nextConfig.distDir === '.next') {
+    errors.push(
+      "- When using Nx you must set a value for 'distDir' in your next.config.js, and the value cannot be '.next'",
+    )
+  }
+  if (!PUBLISH_DIR.startsWith('apps')) {
+    errors.push(
+      "Please set the 'publish' value in your Netlify build config to a folder inside your app directory. e.g. 'apps/myapp/out'",
+    )
+  }
+
+  const expectedConfigFile = path.resolve(netlifyConfig.build.publish, '..', 'next.config.js')
+
+  if (expectedConfigFile !== nextConfig.configFile) {
+    const confName = path.relative(process.cwd(), nextConfig.configFile)
+    errors.push(
+      `- Using incorrect config file '${confName}'. Expected to use '${path.relative(
+        process.cwd(),
+        expectedConfigFile,
+      )}'`,
+    )
+
+    if (existsSync(expectedConfigFile)) {
+      errors.push(
+        `Please move or delete '${confName}'${confName === 'next.config.js' ? ' from the root of your site' : ''}.`,
+      )
+    } else {
+      errors.push(
+        `Please move or delete '${confName}'${
+          confName === 'next.config.js' ? ' from the root of your site' : ''
+        }, and create '${path.relative(process.cwd(), expectedConfigFile)}' instead.`,
+      )
+    }
+  }
+
+  if (errors.length !== 0) {
+    failBuild(
+      // TODO: Add ntl.fyi link to docs
+      ['Invalid configuration', ...errors, 'See the docs on using Nx with Netlify for more information'].join(EOL),
+    )
+  }
+}
+
+module.exports = checkNxConfig

index.js

@@ -3,6 +3,7 @@ const path = require('path')
 const makeDir = require('make-dir')
 
 const { restoreCache, saveCache } = require('./helpers/cacheBuild')
+const checkNxConfig = require('./helpers/checkNxConfig')
 const copyUnstableIncludedDirs = require('./helpers/copyUnstableIncludedDirs')
 const doesNotNeedPlugin = require('./helpers/doesNotNeedPlugin')
 const getNextConfig = require('./helpers/getNextConfig')
@@ -15,7 +16,7 @@ const nextOnNetlify = require('./src')
 // - Between the build and postbuild steps, any functions are bundled
 
 module.exports = {
-  async onPreBuild({ netlifyConfig, packageJson, utils }) {
+  async onPreBuild({ netlifyConfig, packageJson, utils, constants }) {
     const { failBuild } = utils.build
 
     validateNextUsage(failBuild)
@@ -36,6 +37,15 @@ module.exports = {
     // Because we memoize nextConfig, we need to do this after the write file
     const nextConfig = await getNextConfig(utils.failBuild, nextRoot)
 
+    const isNx = Boolean(
+      (packageJson.devDependencies && packageJson.devDependencies['@nrwl/next']) ||
+        (packageJson.dependencies && packageJson.dependencies['@nrwl/next']),
+    )
+
+    if (isNx) {
+      checkNxConfig({ netlifyConfig, packageJson, nextConfig, failBuild, constants })
+    }
+
     if (nextConfig.images.domains.length !== 0 && !process.env.NEXT_IMAGE_ALLOWED_DOMAINS) {
       console.log(
         `Image domains set in next.config.js are ignored.\nPlease set the env variable NEXT_IMAGE_ALLOWED_DOMAINS to "${nextConfig.images.domains.join(