require-ing a json file breaks vitest

[threepointone]

What versions & operating system are you using?

wrangler@4.22.0, @cloudflare/vitest-pool-workers

Please provide a link to a minimal reproduction

https://github.com/threepointone/test-vitest-workers-json-require

Describe the Bug

A require of a JSON file (NOT an import) will fail to run with @cloudflare/vitest-pool-workers, with a cryptic error message SyntaxError: Unexpected token ':'.

Why is this important? Sure, developers might use import to import JSON files, but third party dependencies (like the very popular ajv) do cjs builds, which end up requireing JSON files.

(like here: https://unpkg.com/ajv@8.17.1/dist/core.js)

This works when we do wrangler dev or vite dev, but fails when we run vitest.

Repro

npm install && npm test

Either we should make it work with vitest/vitest-pool-workers, or we should have a better error.

Workaround:

add it to the deps section of vitest.config.ts

Please provide any relevant error logs

No response

[threepointone]

probably the same issue here #9405

[dario-piotrowicz]

As @cllu mentioned in #9405 (comment), predundling the dependency is a valid workaround for these type of issues.

Clearly that's not the best and ideally we should make the vitest module resolution more robust, or at the very least provide a more helpful error message (recommending to prebundle the dependency).

[threepointone]

why can't we automatically do this for json files? it's odd if it works in vite and wrangler but not in vitest.