Question

A backend developer accepts a GitHub Copilot suggestion for a regular expression that validates user-submitted email addresses in a public-facing web form. The regex works correctly against the developer's sample inputs and is merged. Two weeks later, the service experiences intermittent CPU spikes and request timeouts whenever certain malformed inputs are submitted. What responsible-use practice should the developer have applied before merging the Copilot-suggested regex?

Accepted Answer

Reviewed and tested the suggested regex for performance risks such as catastrophic backtracking, including with adversarial and malformed inputs, rather than relying only on happy-path samples

Answer

Rejected the suggestion outright because Copilot should never be used to generate regular expressions of any kind

Answer

Enabled the Copilot duplication detection filter, which would have blocked the vulnerable pattern automatically

Answer

Added a comment above the regex crediting Copilot as the author to satisfy attribution requirements