Issue Review: cloudflare/workers-sdk#5592

Summary

Vitest pool workers crashes when importing the Stripe SDK due to module resolution issues.

Findings

• Created: 2024-04-11
• Updated: 2025-10-30
• Version: wrangler 3.48.0, vitest 1.3.0, vitest-pool-workers 0.1.17 → current
• Component: vitest-pool-workers
• Labels: bug, vitest
• Comments: 5

Key Evidence

• Importing Stripe causes crash: "No such module" errors
• Initially thought related to #5588 but persists after that fix
• Similar issues with other dependencies (semver, @opentelemetry)
• User @gourgouris found workaround: add alias in vitest config to resolve call-bind/callBound
• User @gourgouris has given up on vitest-pool-workers entirely, switched to localhost testing approach
• Related to module resolution issues in workerd runtime

Recommendation

Status: KEEP OPEN

Reasoning: Valid bug affecting popular third-party libraries like Stripe. The module resolution issues are a known limitation of the vitest-pool-workers approach. Workarounds exist (aliases, localhost testing) but the UX is poor. Related to fundamental differences in how workerd handles Node.js modules.

Action: Document known incompatibilities and workarounds. Consider improving error messages when module resolution fails.

Suggested Comment

This issue is related to module resolution in the workerd runtime used by vitest-pool-workers. Some npm packages have Node.js-specific module resolution patterns that don't work in the Workers environment.

Workaround: Add aliases in your vitest config:

alias: {
  'call-bind/callBound': new URL('./node_modules/call-bind/index.js', import.meta.url).pathname,
}

Alternatively, test against a local dev server instead of using vitest-pool-workers for tests involving incompatible packages.