Error in production build when using webpack DLLPlugin, related to sideEffects setting

[mhgamework]

Bug Report

I recently upgraded to latest semantic-ui-react, and now webpack seems to not correctly bundle all semantic-ui-react chunks in production builds.

When i set sideEffects:false in vendor.js build, the problem goes away, so i think this is related to webpack treeshaking and the recent setting of "sideEffects" in semantic-ui-react

Steps

I made a reproduction project, see below. Basically the steps are

• Build a vendor.js that uses the DllPlugin to put semantic-ui-react in a separate bundle
• Build the main.js that uses the dllplugin to reference vendor.js
• Browse to the react app

Expected Result

App should render

Actual Result

App throws on loading webpack imports:

vendor.js:21 Uncaught TypeError: Cannot read property 'call' of undefined
    at __webpack_require__ (vendor.js:21)
    at Module.hasOwn (vendor.js:352)
    at __webpack_require__ (vendor.js:21)
    at Module.<anonymous> (vendor.js:2940)
    at __webpack_require__ (vendor.js:21)
    at Module.<anonymous> (vendor.js:18245)
    at __webpack_require__ (vendor.js:21)
    at Module.<anonymous> (vendor.js:18208)
    at __webpack_require__ (vendor.js:21)
    at Module.module.exports (vendor.js:26903)

Version

0.82.2

Testcase

Uploaded as zip as it is a custom build. Sleek.WebSites.App.zip

• npm install
• npm run start => builds vendor.js, main.js, and serves
• Go to http://localhost:5000
• this fails with error

Workaround:

• Stop serve
• enable sideEffects:false in webpack.config.vendor.js
• npm run start
• Page now doesnt show error

[welcome]

👋 Thanks for opening your first issue here! If you're reporting a 🐞 bug, please make sure you've completed all the fields in the issue template so we can best help.

We get a lot of issues on this repo, so please be patient and we will get back to you as soon as we can.

[layershifter]

@mhgamework Thanks for the report, but it's a Webpack issue. I'm not enough familar with its internals, so please move it there.

---

Similar issues:
webpack/webpack#7425
webpack/webpack#7499 (comment)

---

I've recently checked, without DllPlugin everything works fine.