Workflow/Activity fiber terminates with unhandled error.

[nwidynski]

What version of Effect is running?

latest

What steps can reproduce the bug?

Running the @effect/workflow example with debug logging enabled and the WorkflowEngine.layerMemory instead of the ClusterWorkflowEngine.layer will log unhandled fiber terminations when the activity yields a SendEmailError.

What is the expected behavior?

No errors should be logged.

What do you see instead?

timestamp=2025-12-06T00:35:47.920Z level=DEBUG fiber=#32 message="Fiber terminated with an unhandled error" cause="Error: {\"message\":\"Failed to send email for 123 on attempt 1\",\"_tag\":\"SendEmailError\"} at SendEmail at EmailWorkflow.execute"

Additional information

Maybe we can safely turn the error message off in this instance?

Workflow.ts (intoResult)

  return effect.pipe(
  Effect.withUnhandledErrorLogLevel(Option.none()), // ADDED
  // So we can use external interruption to suspend a workflow
  Effect.fork