Issue Review: cloudflare/workers-sdk#10600

Summary

vitest-pool-workers times out with "resolveId" error when running tests against Workflows in CI, but works locally.

Findings

• Created: 2025-09-10
• Updated: 2025-11-25
• Version: Not specified (user didn't provide vitest-pool-workers version)
• Component: vitest-pool-workers, workflows
• Labels: bug, workflows
• Comments: 4
• Internal Jira: WOR-945

Key Evidence

• Maintainer (@pombosilva) attempted to reproduce in GitLab CI with a simple Workflow but could not reproduce the issue
• Another user (@Pinpickle) reported the same error without Workflows - just using Durable Objects with isolatedStorage: false
• Maintainer now suspects this is an underlying vitest-pool-workers issue, not Workflows-specific
• Error message points to Vitest RPC timeout: Timeout calling "resolveId"
• Reporter did not provide:
  • Exact versions of wrangler, vitest, vitest-pool-workers
  • Full wrangler.toml configuration
  • Minimal reproduction
• Recent vitest-pool-workers fixes (inspector port hang in v0.12.0, new Workflows test handlers) don't address this specific timeout

Recommendation

Status: NEEDS MORE INFO

Reasoning: The maintainer couldn't reproduce the issue, and the scope has expanded to potentially affect non-Workflows setups with isolatedStorage: false. The reporter hasn't provided exact versions or a minimal reproduction, making it difficult to investigate further. Additionally, significant updates to vitest-pool-workers have been released since the issue was reported.

Action: Request updated information from the reporter and ask if the issue persists with the latest vitest-pool-workers version.

Suggested Comment

Hi @hmnd, thanks for reporting this issue. We haven't been able to reproduce it in our testing, and another user has reported a similar error without Workflows (just with Durable Objects and isolatedStorage: false), suggesting this might be a broader vitest-pool-workers issue.

To help us investigate further, could you please provide:

1. Your exact versions of wrangler, vitest, and @cloudflare/vitest-pool-workers
2. Your complete wrangler.toml configuration
3. A minimal reproduction repository if possible

Also, significant improvements have been made to vitest-pool-workers since this was reported. Could you try updating to the latest version (@cloudflare/vitest-pool-workers@0.12.6) and let us know if the issue persists?

If we don't hear back in the next few weeks, we may close this issue. Feel free to reopen if you can provide additional information.