fix(gatsby): more reliable way to use prod versions of react/react-dom (#29683)

back port of #29620 to v2 Fix #28138 (comment) Set `NODE_ENV` to `production` in the child worker that does the SSR in dev. Co-authored-by: Ward Peeters <ward@coding-tech.com> Co-authored-by: Matt Kane <matt@gatsbyjs.com>

Author: 3 people

packages/gatsby/src/utils/dev-ssr/render-dev-html.ts

@@ -2,6 +2,7 @@ import JestWorker from "jest-worker"
 import fs from "fs-extra"
 import { joinPath } from "gatsby-core-utils"
 import report from "gatsby-cli/lib/reporter"
+import { isCI } from "gatsby-core-utils"
 
 import { startListener } from "../../bootstrap/requires-writer"
 import { findPageByPath } from "../find-page-by-path"
@@ -13,7 +14,15 @@ const startWorker = (): any => {
  const newWorker = new JestWorker(require.resolve(`./render-dev-html-child`), {
  exposedMethods: [`renderHTML`, `deleteModuleCache`, `warmup`],
  numWorkers: 1,
- forkOptions: { silent: false },
+ forkOptions: {
+ silent: false,
+ env: {
+ ...process.env,
+ NODE_ENV: isCI() ? `production` : `development`,
+ forceColors: true,
+ GATSBY_EXPERIMENTAL_DEV_SSR: true,
+ },
+ },
  })
 
  // jest-worker is lazy with forking but we want to fork immediately so the user

packages/gatsby/src/utils/webpack.config.js

@@ -697,23 +697,6 @@ module.exports = async (
 
  config.externals = [
  function (context, request, callback) {
- if (
- stage === `develop-html` &&
- isCI() &&
- process.env.GATSBY_EXPERIMENTAL_DEV_SSR
- ) {
- if (request === `react`) {
- callback(null, `react/cjs/react.production.min.js`)
- return
- } else if (request === `react-dom/server`) {
- callback(
- null,
- `react-dom/cjs/react-dom-server.node.production.min.js`
- )
- return
- }
- }
-
  const external = isExternal(request)
  if (external !== null) {
  callback(null, external)