Webpack 5 compatibility

[chadrien]

Goal

The plugin is not working with Webpack 5

Design

The API for plugins changed a little, and it breaks the current implementation

Changeset

• chunk.files not longer holds maps, instead maps are listed in chunks.auxiliaryFiles
• compiler.outputFileSystem is getting reworked to be closer to the actual Node FS, meaning join is deprecated / doomed to disappear as it's not standard. See: Remove fs.join webpack/memory-fs#67 Configurable file system via options.fs webpack/webpack-dev-middleware#370

Testing

• Manually tested by running webpack locally and checking that with these changes source maps are getting sent to Bugsnag
• Updated tests files so the test suite also runs against webpack 5

[chadrien]

I'm not sure what's up the with the node 8 tests for webpack 4 and 5 🤔

[bengourley]

Hi @chadrien thanks so much for the contribution. Webpack 5 support is on our backlog, but it got beaten to the top by other high priority work, so this is a massive help in reducing the scope of the update.

We can see why the tests are failing and it looks like it's not to do with your changes, but rather the version of webpack-cli that gets pulled in not being compatible with Node 8.

We're happy to take it from here, fix the tests, put it through our QA process and get it landed.

Thanks again 🙏

[chadrien]

Yay! That's good to hear 🎉

[djskinner]

Thanks for the contribution @chadrien, this looks great.

According to the migration guide "webpack 5 requires at least Node.js 10.13.0 (LTS)" and according to webpack/webpack-cli#1222 "with webpack-cli v4 we will support only webpack v5 and possibly v4 but not officially, so if there are any problems we suggest to use v3.* if you still want to keep the best compatibility" so I've adjusted the webpack/node version combinations accordingly for CI.

@bengourley I've tested this by upgrading the dashboard project to use webpack 5 and this PR and all works well. Let me know if you'd like to see any further manual testing.