feat: use internal functions dir (#549)

* feat: use internal functions dir

* fix: update test

Author: ascorbic

index.js

@@ -1,8 +1,10 @@
 const { readdirSync, existsSync } = require('fs')
 const path = require('path')
 
+const { yellowBright, greenBright } = require('chalk')
 const makeDir = require('make-dir')
 const { satisfies } = require('semver')
+const glob = require('tiny-glob')
 
 const { restoreCache, saveCache } = require('./helpers/cacheBuild')
 const checkNxConfig = require('./helpers/checkNxConfig')
@@ -23,6 +25,8 @@ const REQUIRED_BUILD_VERSION = '>=15.11.5'
 
 module.exports = {
   async onPreBuild({ netlifyConfig, packageJson, utils, constants = {} }) {
+    const { FUNCTIONS_SRC = DEFAULT_FUNCTIONS_SRC, INTERNAL_FUNCTIONS_SRC, IS_LOCAL, NETLIFY_BUILD_VERSION } = constants
+
     const { failBuild } = utils.build
 
     validateNextUsage({ failBuild, netlifyConfig })
@@ -36,7 +40,7 @@ module.exports = {
       return
     }
     // We check for build version because that's what's available to us, but prompt about the cli because that's what they can upgrade
-    if (constants.IS_LOCAL && !satisfies(constants.NETLIFY_BUILD_VERSION, REQUIRED_BUILD_VERSION)) {
+    if (IS_LOCAL && !satisfies(NETLIFY_BUILD_VERSION, REQUIRED_BUILD_VERSION, { includePrerelease: true })) {
       return failBuild(
         `This version of the Essential Next.js plugin requires netlify-cli@4.4.2 or higher. Please upgrade and try again.
 You can do this by running: "npm install -g netlify-cli@latest" or "yarn global add netlify-cli@latest"`,
@@ -66,6 +70,19 @@ You can do this by running: "npm install -g netlify-cli@latest" or "yarn global
         `The Essential Next.js plugin now supports reading image domains from your Next config, so using NEXT_IMAGE_ALLOWED_DOMAINS is now deprecated. Please set images.domains in next.config.js instead, and remove the NEXT_IMAGE_ALLOWED_DOMAINS variable.`,
       )
     }
+
+    if (INTERNAL_FUNCTIONS_SRC && existsSync(FUNCTIONS_SRC)) {
+      const oldFunctions = await glob('next_*', { cwd: FUNCTIONS_SRC })
+
+      if (oldFunctions.length !== 0) {
+        console.log(yellowBright`
+Detected the following functions that seem to have been generated by an old version of the Essential Next.js plugin. 
+The plugin no longer uses these and they should be deleted to avoid conflicts.\n`)
+        console.log(greenBright`• ${oldFunctions.join('\n• ')}
+`)
+      }
+    }
+
     await restoreCache({ cache: utils.cache, distDir: nextConfig.distDir, nextRoot })
 
     // Exit the build process on unhandled promise rejection. This is the default in Node 15+, but earlier versions just warn.
@@ -75,7 +92,7 @@ You can do this by running: "npm install -g netlify-cli@latest" or "yarn global
   async onBuild({
     netlifyConfig,
     packageJson,
-    constants: { PUBLISH_DIR = DEFAULT_PUBLISH_DIR, FUNCTIONS_SRC = DEFAULT_FUNCTIONS_SRC },
+    constants: { PUBLISH_DIR = DEFAULT_PUBLISH_DIR, INTERNAL_FUNCTIONS_SRC, FUNCTIONS_SRC = DEFAULT_FUNCTIONS_SRC },
     utils,
   }) {
     const { failBuild } = utils.build
@@ -95,7 +112,7 @@ You can do this by running: "npm install -g netlify-cli@latest" or "yarn global
 Could not find "${distDir}" after building the site, which indicates that "next build" was not run or that we're looking in the wrong place. 
 We're using the config file ${configFile}, and looking for the dist directory at ${dist}. If this is incorrect, try deleting the config file, or
 moving it to the correct place. Check that your build command includes "next build". If the site is a monorepo, see https://ntl.fyi/next-monorepo 
-for information on configuring the site. If this is not a Next.js site, or if it uses static export, you should remove the Essential Next.js plugin. 
+for information on configuring the site. If this is not a Next.js site or if it uses static export, you should remove the Essential Next.js plugin. 
 See https://ntl.fyi/remove-plugin for instructions.
       `)
     }
@@ -104,7 +121,7 @@ See https://ntl.fyi/remove-plugin for instructions.
 
     await makeDir(PUBLISH_DIR)
     await nextOnNetlify({
-      functionsDir: path.resolve(FUNCTIONS_SRC),
+      functionsDir: path.resolve(INTERNAL_FUNCTIONS_SRC || FUNCTIONS_SRC),
       publishDir: netlifyConfig.build.publish || PUBLISH_DIR,
       nextRoot,
     })