Race Condition

Race conditions happen when two or more operations that should happen in a specific order end up executing in a different sequence. For example, a user clicks a submit button, and the application starts saving to the database while simultaneously updating the UI. If the UI update completes before the save and the save then fails, the user sees a success state that is false.

These bugs are notoriously difficult to detect because they often depend on specific timing conditions that may not occur consistently. The app might work correctly 99 times and fail on the 100th try due to a slightly slower network response. AI-generated code is particularly prone to race conditions because AI tools often generate asynchronous code without proper safeguards for timing-dependent operations.

Human testers are often the ones who discover race conditions because they interact with applications in varied and sometimes rapid ways. Double-clicking a button, quickly navigating between pages, or performing actions during loading states are common real-world behaviors that expose race conditions. These are patterns that automated tests rarely cover.