Instrument and Diagnose a Silent Failure

Help Copilot add logging and guards to diagnose code that fails silently.

category:debugging

logging

observability

error-handling

Prompt

The following code sometimes fails silently or behaves incorrectly.
  
  1. Add structured logging or console output at key decision points.
  2. Add error handling where appropriate (try/catch or result types).
  3. Add guards for invalid input or unexpected states.
  4. Suggest how to reproduce or narrow down the bug.
  
  Code:
  
  [Paste code here]