What does a bug do? - briefly
A «bug» causes software to produce incorrect or unintended results, potentially leading to crashes or data corruption. It stems from coding errors, design oversights, or unexpected interactions within the system.
What does a bug do? - in detail
A software defect represents a deviation between actual program behavior and the specification. The deviation arises from incorrect logic, misuse of APIs, or unintended interactions among components.
Typical categories include:
- Logical error: condition evaluates incorrectly, producing wrong results.
- Boundary error: off‑by‑one or overflow when handling limits.
- Null reference: attempt to access an object that has not been instantiated.
- Concurrency issue: race condition or deadlock caused by unsynchronized threads.
- Resource leak: failure to release memory, file handles, or network sockets.
Consequences manifest as:
- Application crash or abrupt termination.
- Incorrect data displayed or stored.
- Degraded responsiveness or excessive CPU usage.
- Exposure of security vulnerabilities through unintended access paths.
Detection mechanisms rely on:
- Runtime logs that capture exceptions and stack traces.
- Automated test suites exercising functional and edge‑case scenarios.
- Static analysis tools scanning source code for known patterns.
- Monitoring systems alerting on abnormal performance metrics.
Impact assessment considers:
- Data integrity loss requiring restoration procedures.
- User dissatisfaction leading to reduced adoption.
- Financial overhead for emergency patches and support.
Resolution follows a reproducible workflow:
- Replicate the failure under controlled conditions.
- Isolate the responsible code segment through debugging or instrumentation.
- Apply a corrective change that restores compliance with the specification.
- Validate the fix with regression tests covering affected and related functionality.
- Deploy the updated version following standard release protocols.
«A bug is a feature that works incorrectly». This maxim captures the essence of unintended behavior that must be identified, understood, and eliminated to maintain reliable software operation.