update tests for webpack 5

[sokra]

• Upgraded all tests to webpack 5 and validated if they still work or now work
• Updated asset imports from import "./image.png" to new URL("image.png", import.meta.url) which is the new recommended style for assets
  • In contrast to import this is covered by web specs and fully working without bundler (more future-proof)
  • Old style would still work
• tests/code-splitting/subtests/between-workers/webpack changed from fail to pass
  • Workers share chunks with the web part.
• tests/code-splitting/subtests/between-new-worker-type/webpack changed from fail to partial
  • All worker types are supported by default, most worklets can be easily added. Partial because the audioWorklet doesn't work yet.
• tests/code-splitting/subtests/multi-entry/webpack changed from partial to pass
  • This is now documented
• tests/code-splitting/subtests/splitting-modules/subtests/multi-entry/webpack changed from fail to pass
  • Multiple entries can now be optimized separately
• tests/hashing/subtests/hash-on-final-content/webpack changed from fail to pass
  • Contenthash is now equal to slice of hex digest of md4 hash of content by default
• tests/transformations/subtests/dead-code-dynamic/webpack changed from fail to partial
  • A magic comment can be used to tree shake import(). Partial because it's manual.
• Some custom plugins and loaders have been updated and/or simplified

[surma]

@sokra Thank you so much for whipping up an entire PR for Webpack 5. This is huge!

We are currently kinda heads down in the preparations for the Chrome Dev Summit 2020, so it will be a week or so before we get back to this. We were also previously discussing how we can keep both Webpack 4 and 5 available on tooling.report. But we’ll get back to that.

Again, thanks for putting in all this work!

[sokra]

We were also previously discussing how we can keep both Webpack 4 and 5 available on tooling.report. But we’ll get back to that.

I copied all existing webpack folders into a webpack-4 folder and the new webpack folder is now webpack 5. Once you have the infrastructure you can use the webpack-4 folder in addition.

[developit]

Apologies for the delay - I should be able to review this within the week!

[pboling]

Would be very useful to have this updated reference for Webpack 5 on https://bundlers.tooling.report/ - I fear if I hadn't checked the issue / pull request backlog for the project I may have made a different choice in a bundler. Looks like I am going to stick with webpack.

[sokra]

Anything I can help you with getting this reviewed?

[developit]

@sokra can you enable "Allow edits and access to secrets by maintainers" for your PR?

[sokra]

@sokra can you enable "Allow edits and access to secrets by maintainers" for your PR?

It's already enabled.

[developit]

I've skipped over all the webpack-4 tests since we agreed to simply remove them. There were no material changes when I diffed them against the webpack directories currently on the dev branch.

If it makes reviews easier we could delete those directories. For now I just ran this in DevTools to mark them as hidden (note: this will freeze the page for around 1 minute):

document.querySelectorAll('a[title*="/webpack-4/"]').forEach(n => n.parentNode.nextElementSibling.querySelector('input[type=checkbox]').click());

[sokra]

I've skipped over all the webpack-4 tests since we agreed to simply remove them. There were no material changes when I diffed them against the webpack directories currently on the dev branch.

ok. I removed the commit which copies them over.

[jakearchibald]

Other than the few comments I made, this looks good to go. Thanks @sokra for putting this PR together, some great changes in webpack 5.

[developit]

I'm pushing the merge button!

[jakearchibald]

Publishing to live now. It'll be up in a couple of mins.