`UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'length' of null` (5.47.0)

Bug report

The latest version of webpack (5.47.0) causes our build pipeline to fail due to some missed null check. Our project has both the backend and frontend built and deployed as a single unit and no frontend changes were made between a backend-exclusive code change successfully merged and deployed yesterday evening and our builds (now failing) this morning.

[Superoryco]

Electron Forge with Webpack + Typescript

Actually, I’m also using Electron Forge with Webpack + Typescript, and electron-store, never tried ‘npm run make’ before.

One note, I noticed that I can reproduce the error from streamChunksOfCombinedSourceMap.js when I run npm run make and there’s no problems when I run npm start

Confirm: For 5.47.1, it did fix the ‘length of null’ error from ‘ReplaceSource.js’, with ‘npm run make’, still throw same error from ‘streamChunksOfCombinedSourceMap.js’,

Also, to fix this bug, I think we can just apply this, after I digg into the code:

originalSourceLines = originalSource? originalSource.match(SPLIT_LINES_REGEX): null;

originalSourceLines is a nullable variable but we missed the null check, that’s it, I think.

[modestfake]

Alright, I was able to reproduce it.

Steps to reproduce:

# https://www.electronforge.io/templates/typescript-+-webpack-template
npx create-electron-app reproduce-webpack-source-error --template=typescript-webpack

cd reproduce-webpack-source-error

npm ls webpack-sources
# repro-webpack-sources-bug@1.0.0 /Users/dev/repro-webpack-sources-bug
# └─┬ @electron-forge/plugin-webpack@6.0.0-beta.59
#   └─┬ webpack@5.47.1
#     └── webpack-sources@3.1.1

# This one works fine after the latest fix
npm start

# This one work for now
npm run make

# But let's install electron-store and init it (https://github.com/sindresorhus/electron-store)
npm i electron-store

Open /reproduce-webpack-source-error/src/index.ts Add

import Store from 'electron-store'

const store = new Store()

# Then run this one more time
npm run make

This time it should fail. I guess it might be related to native_modules but I don’t know how it works. Maybe this part of the Electron Forge Webpack config.