Common Bugs in GitHub Copilot-Generated Code

Copilot generates completions based on patterns in its training data, not understanding of your specific logic. This produces code that looks correct and passes casual review but contains subtle logical errors

Copilot introduces subtle bugs through seemingly correct completions: off-by-one errors in loops, wrong comparison operators (=== vs ==, > vs >=), incorrect variable names when similar variables exist in scope, and edge cases in conditional logic that look right on quick review but fail with specific inputs

Start by running your app through its complete user flow — sign up, use every feature, try edge cases like empty inputs and invalid data. Most GitHub Copilot bugs surface when you go off the happy path. Use your browser's developer tools to watch for console errors, failed network requests, and unhandled promise rejections. TypeScript's strict mode will catch many issues at compile time if it's not already enabled.

For async errors, wrap every server-side operation in try/catch blocks and return meaningful error messages. For state bugs, consider whether the state belongs in the URL, in a server component, or in client state — GitHub Copilot often defaults to client state when server state would be more appropriate. For data fetching issues, implement proper loading and error states for every data-dependent component.

The best way to prevent GitHub Copilot bugs from reaching production: enable TypeScript strict mode, add ESLint rules for common mistakes (no-floating-promises, exhaustive-deps), and write tests for critical user flows. Even basic smoke tests catch the majority of issues.