5.0.0-beta.14 with react-hot-loader breaks the app in development mode: "ReferenceError: exports is not defined"

[wojtekmaj]

Note: This has also been reported in react-hot-loader repo.

Bug report

What is the current behavior?

I'm getting an error "ReferenceError: exports is not defined" when running the application that imports d3-array in development mode (with react-hot-loader) built with 5.0.0-beta.14 and up.

Here's the exact error:

Uncaught ReferenceError: exports is not defined
    at register (cross.js?0cbf:23)
    at eval (cross.js?0cbf:23)
    at Object.../node_modules/d3-array/src/cross.js (charts.js:376)
    at __webpack_require__ (src.js:6070)
    at fn (src.952fd4b1.js:6330)
    at eval (index.js:18)
    at Object.../node_modules/d3-array/src/index.js (charts.js:496)
    at __webpack_require__ (src.js:6070)
    at fn (src.js:6330)
    at eval (band.js:5)

Reproducible repo

Any of the following seem to unbreak the app:

• removing d3-array import (duh)
• export default hot(Root) -> export default Root
• applying react-hot-loader/webpack loader to /node_modules\/react-dom/ only and not /node_modules/

What is the expected behavior?

"Uncaught ReferenceError: exports is not defined" not to be thrown when executing Webpack-bundled code.

Other relevant information:
webpack version: 5.0.0-beta.14-5.0.0-beta.16
Node.js version: 12.16.2
Operating System: macOS Catalina
Additional tools: n/a

Tested other versions of Webpack, changing absolutely nothing but the Webpack version, and here's my findings:

Version	Crashes?
4.43.0	✅ No
5.0.0-beta.12	✅ No
5.0.0-beta.13	✅ No
5.0.0-beta.14	❌ Yes
5.0.0-beta.16	❌ Yes

[theKashey]

Because nor __webpack_exports__ nor exports are defined.

[webpack-bot]

This issue had no activity for at least three months.

It's subject to automatic issue closing if there is no activity in the next 15 days.

[webpack-bot]

Issue was closed because of inactivity.

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