fix(config): treat all files as ESM on deno

[marvinhagemeister]

Description

The CJS detection logic that checks whether the CJS entry of vite itself is used is based around package.json detection. With Deno this assumption is not true anymore as most Deno projects don't have a package.json file. Instead they either have a deno.json or a deno.jsonc file. Projects in Deno are always in ESM too.

When using vite in Deno you'd always see this warning unless you added a package.json with type: module:

Ultimately, this is caused by the check here

vite/packages/vite/src/node/utils.ts

Line 430 in 35cf59c

return pkg?.data.type === 'module'

Which infers that the current project is in CJS. This PR addresses that by making vite aware of Deno projects. When running inside Deno, we'll not just check for package.json, but also deno.json and deno.jsonc too.

I'm not too familiar with the testing setup here in vite and would need some pointers for adding a test. Where do these go here?

Fixes denoland/deno#25574

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[sapphi-red]

findNearestPackageData is a hot spot and probably should avoid adding fs accesses if possible.
Does having deno.json/deno.jsonc in node_modules change the behavior?
If it doesn't, I wonder if we can change this line

vite/packages/vite/src/node/config.ts

Line 1511 in 35cf59c

const isESM = isFilePathESM(resolvedPath)

to

const isESM = process.versions.deno || isFilePathESM(resolvedPath) 

instead.

[marvinhagemeister]

Thanks for the tip! I had a feeling that putting the check in findNearestPackageData wasn't the right place. Your suggestion of putting it in the config loading logic is much better. Updated the PR.

EDIT: The test that fails in CI fails in main for me too.