fix: apply Vite resolving algorithm to node_modules libraries

[sheremet-va]

This PR adds experimental loader and conditions, so native Node resolving algorithm knows about Vite's resolving algorithm.

This is a giant breaking change, but still should not affect a lot of people. This fixes issues when people applied custom conditions and they were working in Vite, but didn't work in Vitest, because it was imported from another library. This PR also allows applying alias to external libraries - this is useful for preact, for example.

We still don't allow mocking external libraries within another external library!

Closes #1638

[antfu]

Can we have a flag to toggle this behavior?

[sheremet-va]

Can we have a flag to toggle this behavior?

How would you call it? I personally don't think it should be toggable. From my experience with Vitest issues for the past several months, is that people expect aliasing to work as it works in Jest (also inside node_modules)

[antfu]

Ok, we could try and see how it works

[thebuilder]

After upgrading to v0.20.1, most of my tests are now failing with:

SyntaxError: Named export '__assign' not found. The requested module 'tslib' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'tslib';
const { __assign } = pkg;

It seems to be caused by framer-motion using tslib. The package does include an exports field and module support, so a bit weird why this is popping up. Thinking it's related to how node modules are resolved now?

[sheremet-va]

After upgrading to v0.20.1, most of my tests are now failing with:

SyntaxError: Named export '__assign' not found. The requested module 'tslib' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'tslib';
const { __assign } = pkg;

It seems to be caused by framer-motion using tslib. The package does include an exports field and module support, so a bit weird why this is popping up. Thinking it's related to how node modules are resolved now?

Please, open a separate issue with minimal reproduction. Thank you! 😄

[cameronbraid]

This change breaks projects using yarn pnp

0.19.1 works, when upgrading to 0.20 I get

Serialized Error: {
  "errors": [
    [Error: Cannot find module '/workspace/octane/.yarn/__virtual__/vitest-virtual-b7339852d0/0/cache/vitest-npm-0.20.2-9730ec2bf1-eea156689f.zip/node_modules/vitest/dist/loader.mjs' imported from /workspace/octane/
Did you mean to import /workspace/octane/.yarn/__virtual__/vitest-virtual-b7339852d0/0/cache/vitest-npm-0.20.2-9730ec2bf1-eea156689f.zip/node_modules/vitest/dist/loader.mjs?],
  ],
}

[cameronbraid]

Looks like its already reported #1758