publicRuntimeConfig shouldn’t be undefined on build

[tusbar]

Bug report

Describe the bug

v8.1.1-canary.62 (or maybe 3aed76f) (re-)introduces an issue with how I use (and recommend how to use) https://github.com/tusbar/next-runtime-dotenv.

To Reproduce

This breaks on build as publicRuntimeConfig is undefined at build time:

const {
  publicRuntimeConfig: {MY_API_URL}
} = getConfig()

Expected behavior

publicRuntimeConfig used to be {} at build time.

System information

• OS: macOS
• Version of Next.js: 8.1.1-canary.62

Additional context

This is not the first time this breaks, maybe it would be nice to add a test. It used to work fine with 8.0.4, it’s broken in 8.1.0 and used to work fine in canary before 8.1.1-canary.62. Broken in 9.0 as well.

[tusbar]

@timneutkens could we have a consistent behavior for this? Thanks.

[cbarratt]

I'm using the built in method of using publicRuntimeConfig and not the above plugin and also receive the same error message on build

[tusbar]

@cbarratt the plugin just pre-fills the runtime configuration with environment variables using dotenv.

Accessing the configuration is not different from the doc.

[vitorhsb]

I also received the same error message on build and think I figured it out why. It has to do with Automatic static optimization introduced in Next 9, or 8.1.1-canary.62.

Following the documentation that states "This determination is made by whether or not the page has blocking data requirements through using getInitialProps." I ended up adding getInitialProps to every page in my application and the error went away.
Since there was none getInitialProps statement in some pages, during build it would consider this pages as static and does not expose runtime env configuration.

[egdelwonk]

I'm seeing the same error on build, but am getting notices that Automatic static optimization is opt-out, so not sure if it's related @vitorhsb.

A few details to help debug:

• Works with Next@8.1.0
• Fails with Next@9.0.0
• I'm using Apollo and have a custom getInitialProps in _app.js to renderDataFromTree. Not sure if that matters.
• I'm also using withPlugins in my next.config.js file.
• I'm manually calling require("dotenv").config(); in the top of my next.config.js file. (not using next-runtime-dotenv)

Build Output

Compiled successfully.

Warning: You have opted-out of Automatic Prerendering due to `getInitialProps` in `pages/_app`.
Read more: https://err.sh/next.js/opt-out-automatic-prerendering

> Build error occurred
{ TypeError: Cannot read property 'publicRuntimeConfig' of undefined
    at Object.ejXW (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:8637:28)
    at __webpack_require__ (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:23:31)
    at Object.nrlr (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:10516:13)
    at __webpack_require__ (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:23:31)
    at Object.Jrf2 (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:4298:14)
    at __webpack_require__ (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:23:31)
    at Module.oSZ7 (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:12982:12)
    at __webpack_require__ (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:23:31)
    at Object.12 (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:488:18)
    at __webpack_require__ (/Users/egdelwonk/dev/lp/frontend/build/server/static/yNatTl7kpzkSAKqWfkbLL/pages/journals/templates/destination/detail.js:23:31) type: 'TypeError', '$error': '$error' }
npm ERR! code ELIFECYCLE
npm ERR! errno 1

[ijjk]

Hi, I'm not able to reproduce this error, could someone who is encountering this issue add a link to a repo or their next.config.js?

On a minimal project publicRuntimeConfig and serverRuntimeConfig are both being populated during build. We also do have a test for this here

[timdavish]

Hey, I am also seeing this error on production builds after upgrading to 9.0.0. It worked fine on 8.1.0.

Doing the following:

import getConfig from 'next/config'
console.log(getConfig())

seems to randomly switch between printing the config and undefined during the build.

Here is our next.config.js:

const withCss = require('@zeit/next-css')
const withSass = require('@zeit/next-sass')
const withImages = require('next-images')

const isDev = process.env.NODE_ENV === 'dev'

const withSassConfig = {
  cssModules: true,
  cssLoaderOptions: {
    modules: true,
    importLoaders: 1,
    localIdentName: isDev ? '[name]__[local]--[hash:base64:5]' : '[sha1:hash:hex:4]',
  },
}

const nextConfig = {
  publicRuntimeConfig: {
    // config vars..
  },
}

const config = {
  ...withSassConfig,
  ...nextConfig,
  webpack: webpackConfig => webpackConfig,
}

module.exports = withCss(withSass(withImages(config)))