fix(commonjs): replace top-level this with exports name

[bluwy]

Rollup Plugin Name: commonjs

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

If yes, then include "BREAKING CHANGES:" in the first commit message body, followed by a description of what is breaking.

List any relevant issue numbers: vitejs/vite#4083 (comment)

EDIT: I guess it could be considered a breaking change is someone relied on the bug, but I usually still think of it as a bug fix.

Description

This fixes compatibility with @mediapipe/selfie_segmentation reported from the Vite issue above.

The issue is that the library ships with this code:

;(() => {
  this.namedExports = 'foo'
}).call(this)

Where this is used instead of module.exports, but in practice they're equal (stackblitz example). However, @rollup/plugin-commonjs replaces this as commonjsGlobal so it points to globalThis/window/global/self which is incorrect.

This PR updates to replace this to the exportsName, which should work like module.exports. I also updated the test that was testing the previous behaviour.

[shellscape]

Thanks for the PR. This looks like a breaking change since the output will change significantly. I would like to get eyes on this from @guybedford and @lukastaegert before we merge.

[bluwy]

Thanks. If we do a breaking change, perhaps we can also sneak #1425 (comment) (changes strictRequires to true by default). I was also checking the commonjs issue yesterday.

[lukastaegert]

The changes look good to me. I agree that the change is a bug fix as the default behavior in Node is indeed that this is NOT the global object. But it is indeed possible to rely on the wrong behavior, so I fear we need to make it breaking. And if we do that, I agree that we should use the chance to change strictRequires: true to not spam major versions.

[shellscape]

@bluwy can we get that strictRequires change into here as well?

[bluwy]

Hey, sorry for the silence here. I was actually working on a PR to change the strictRequires default, but that made a lot of tests failed. Besides updating the fixtures, seems like some tests are actual fails that expects the auto option, which seems to fix things that true didn't (?).

The changes are quite large so it's probably better as a separate PR. I'll submit it shortly and we could see how to work on it from there.