Software bugs are an inevitable part of the development process, but they can be classified into three major categories: implementation bugs, specification bugs, and absent specification bugs.
1. Implementation bugs:
Occur during the coding phase of software development and are not present in the requirements or design phases. These bugs can arise when the code does not align with the specifications, leading to unexpected behaviors. For example, if a username is supposed to contain only alphabets and numerals, but the developer allows symbols as well, this would be an implementation bug. Such bugs are common, but can be prevented through rigorous testing and quality assurance practices.
2. Specification bugs:
On the other hand, occur during the creation of technical specifications for the software. These bugs can arise when the specifications do not align with industry standards or best practices. For instance, if the specification states that an incorrect password should display the error message "Incorrect Password!" instead of the more secure message "Incorrect Username or Password!", this would be a specification bug. Such bugs can cause delays and impact the development cycle, which is why it is important to catch them early.
3. Absent specification bugs:
These type of bugs that arise because certain workflows or use cases were not considered during the creation of the specifications. For example, if a website specification does not mention support for HTTPS, it may be assumed that HTTPS support is not needed. However, this assumption can lead to security vulnerabilities in the product. These bugs are particularly challenging to prevent as they arise from oversights, and may only be detected later in the development process or after release.
Overall, preventing software bugs requires a combination of rigorous testing, adherence to industry standards, and careful consideration of use cases and workflows during the specification phase.