Cannot find module 'webpack' in CI environment

[tortilaman]

Bug report

Describe the bug

In CI environments, when initially trying to start the server after build, it errors out with the following error:

ERR Error: Cannot find module 'webpack'
ERR Require stack:
ERR - /home/vcap/deps/0/node_modules/mini-css-extract-plugin/dist/index.js
ERR - /home/vcap/deps/0/node_modules/mini-css-extract-plugin/dist/cjs.js
ERR - /home/vcap/deps/0/node_modules/@zeit/next-css/css-loader-config.js
ERR - /home/vcap/deps/0/node_modules/@zeit/next-sass/index.js
ERR - /home/vcap/app/next.config.js
ERR - /home/vcap/deps/0/node_modules/next/dist/next-server/server/config.js
ERR - /home/vcap/deps/0/node_modules/next/dist/next-server/server/next-server.js
ERR - /home/vcap/deps/0/node_modules/next/dist/server/next.js
ERR - /home/vcap/app/routes/next.js
ERR - /home/vcap/app/helpers/startServer.js
ERR - /home/vcap/app/server.js
ERR     at Function.Module._resolveFilename (internal/modules/cjs/loader.js:625:15)
ERR     at Function.Module._load (internal/modules/cjs/loader.js:527:27)
ERR     at Module.require (internal/modules/cjs/loader.js:683:19)
ERR     at require (internal/modules/cjs/helpers.js:16:16)
ERR     at Object.<anonymous> (/home/vcap/deps/0/node_modules/mini-css-extract-plugin/dist/index.js:7:16)
ERR     at Module._compile (internal/modules/cjs/loader.js:776:30)
ERR     at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
ERR     at Module.load (internal/modules/cjs/loader.js:643:32)
ERR     at Function.Module._load (internal/modules/cjs/loader.js:556:12)
ERR     at Module.require (internal/modules/cjs/loader.js:683:19) {
ERR   code: 'MODULE_NOT_FOUND',
ERR   requireStack: [
ERR     '/home/vcap/deps/0/node_modules/mini-css-extract-plugin/dist/index.js',
ERR     '/home/vcap/deps/0/node_modules/mini-css-extract-plugin/dist/cjs.js',
ERR     '/home/vcap/deps/0/node_modules/@zeit/next-css/css-loader-config.js',
ERR     '/home/vcap/deps/0/node_modules/@zeit/next-sass/index.js',
ERR     '/home/vcap/app/next.config.js',
ERR     '/home/vcap/deps/0/node_modules/next/dist/next-server/server/config.js',
ERR     '/home/vcap/deps/0/node_modules/next/dist/next-server/server/next-server.js',
ERR     '/home/vcap/deps/0/node_modules/next/dist/server/next.js',
ERR     '/home/vcap/app/routes/next.js',
ERR     '/home/vcap/app/helpers/startServer.js',
ERR     '/home/vcap/app/server.js'
ERR   ]
ERR }

It seems there is an issue with the mini-css-extract-plugin as part of @zeit/next-sass.
We've been successfully using this plugin for over a year, with different versions of next.js from 6.0 up to 9.2, and a seemingly unrelated commit is now introducing this error that prevents the site from starting.

This was reported previously in the mini-css-extract-plugin repo: webpack-contrib/mini-css-extract-plugin#198

To Reproduce

I know this isn't helpful, but I'm unable to provide a repository at this time.

Expected behavior

The app should start.

Screenshots

If applicable, add screenshots to help explain your problem.

System information

• OS: Linux
• Version of Next.js: 9.2.2, "@zeit/next-sass": "^1.0.1",
• Version of Node.js: 12.6.0

Additional context

Add any other context about the problem here.

[timneutkens]

This issue is not actionable so I'm not sure what to do here.

[tortilaman]

I seem to have found a workaround, so while not an issue for me, maybe an issue for others?

[timneutkens]

Will close this issue then as no reproduction is provided so we can't investigate.

[robianmcd]

I'm running into this issue too. @tortilaman what was your workaround?

[Danelund]

I have this as well

[Danelund]

running

I'm running into this issue too. @tortilaman what was your workaround?

npm i --save @zeit/next-sass fixes this for me

[tortilaman]

Thanks @Danelund. I no longer had access to the repo I was working on when I encountered this bug, so wasn't really able to figure out the solution I came to.

[ashispavan]

I am facing this issue after upgrading to NextJS 10. It only happens in CI env.
@robianmcd Were you able to figure out a workaround for this?

[geun]

I am facing this issue after upgrading to NextJS 10. It only happens in CI env.
@robianmcd Were you able to figure out a workaround for this?

Same here

[MrNghia123]

Next 10 run successfully for several builds for me 3 days ago, now it started to show the same error.
Downgraded to 9.5.5 and build successfully.

[soly2014]

same issue here

[iampeterbanjo]

Rolling back to [email protected] fixes webpack dependency.

[blaxk]

In the package-lock.json file of the [email protected].* version, I noticed the difference from the [email protected] version.
I noticed that the webpack dependencies disappeared in the package-lock.json file of the [email protected].* version.

If you add webpack to package.json, you can use it without rollback.

"dependencies": {
    "webpack": "^4.46.0"
}

[saifbechan]

@blaxk I can confirm this works indeed. My version of webpack is higher.

"webpack": "^5.19.0"

[isggwp]

it happens in next 10.0.6 . we need reproduce

[timneutkens]

#21679 (comment)

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.