Fixing software bugs is an inevitable part of software development. However, sometimes the process of fixing one bug can introduce new ones, causing more frustration and delays. How can you avoid this scenario and ensure that your bug fixes are effective and reliable? Here are some tips and best practices that can help you prevent new bugs from creeping into your code.
Before you jump into writing code to fix a bug, you need to understand what is causing it and how it affects the functionality and performance of your software. You can use debugging tools, logs, tests, and user feedback to identify the source and the impact of the bug. By understanding the root cause, you can avoid making assumptions, oversights, or unnecessary changes that could introduce new bugs.
Very often it is underestimated the step of understanding the root cause of an issue. To me this is the most crucial step and the one that sets the pase for an effective solution. When the root cause of an issue is not properly identified, considerable development time is waisted.
One way is to thoroughly understand the existing code and its dependencies before making changes. Testing your fixes in isolation can also help catch issues early on. Another important thing is to use available documentation effectively. Keeping detailed records of changes helps you and others understand the codebase. Additionally, writing unit tests for the existing code can act as a safety net, ensuring that your fix doesn't inadvertently break other functionalities.
The problem is.. you can't. But you still can: - try to make your system logic clear and concise; - detect bugs on earliest phases possible by testing constantly and thoroughly; - try to decrease its impact by making many small code changes instead of The Great One. Sorry, but bugs is an imminent part of software development and reflects flaws in people thinking process. It's OK - it is only minor flaws. The major flaw is to do nothing and that flaw you should definitely avoid.
When fixing software bugs, a thorough understanding is key. Write targeted test cases for automation, ensuring swift and consistent verification. Regression testing on the broader codebase prevents disruptions. Peer reviews and code linting catch potential issues, while isolated changes minimize unintended consequences. Version control documents changes for easy reversibility. Open communication within the team and user involvement in testing reveal unforeseen issues. Monitoring and logging post-deployment aid in rapid bug identification and resolution. In essence, a meticulous, multi-layered approach minimizes the risk of introducing new bugs when resolving existing issues.
Besides that you can also use unit test to help you assert your changes, be so sure about your fixing. One other thing is to defibe the scoop of this bug and all modules related to it. Also cover all possible scenarios related to this bug.
One of the best ways to avoid introducing new bugs is to write tests that can verify your bug fix and detect any potential regressions or side effects. You can use test-driven development (TDD) or behavior-driven development (BDD) methodologies to write tests before fixing the bug, and then use them to guide your coding and refactoring. This way, you can ensure that your code meets the specifications and expectations, and that it does not break any existing functionality.
Some of cool ways I can think of 1. Bug Bounties : Bug bounty is a cool way of turning bug identification within team into a positive, collective effort, fostering a culture of shared responsibility for code quality. 2. Table top exercise : Before making changes, conduct table top drills where the team imagines the project has failed due to introduced bugs. This exercise helps anticipate risks and implement preventive measures. 3. Error Budgets: Set error budgets to define the acceptable level of bugs. This encourages a balance between innovation and stability, forcing the team to be mindful of the impact of changes. Remember, the key is to foster a culture of shared responsibility, continuous learning, and proactive prevention.
In my experience, having good set of regression test cases would catch the newly introduced bugs as part of change. With modern CICD pipeline, we can even avoid code checkin if there are regression test failures.
Test driven and behavioural driven development enables the developer to understand the existing behaviour of the system or application. On top of this thinking through the positive and negative scenarios will meet the goal of catching any bugs early in development.
From a technical perspective: 1) Data Flow Testing Cca. 50% of defects are caused by data, not code, so you need to identify how will the new code influence the data "downstream" and what consequences will that have on the other code modules. Distinguish the P-data (influence code flow and logic) from C-data (calculation results and output). 2) Regression test case suite Should be obvious, but few caveats need clarification. A Regression test case suite is not the same as unit tests, nor smoke tests. Regression test case suite means that you take the same comprehensive test case suite which was used for system testing of the new feature, then re-run it each time any of it's code was changed or could be affected by P-data changes upstream.
Thorough testing is crucial. Create comprehensive test cases that cover various scenarios, conduct regression testing, and automate tests when possible. Additionally, adhere to coding standards, review changes carefully, and consider pair programming for critical fixes.
Another way to avoid introducing new bugs is to follow coding standards and conventions that can improve the readability, maintainability, and quality of your code. You can use code style guides, linters, formatters, and code reviews to ensure that your code is consistent, clean, and follows the best practices of your programming language and framework. By following coding standards and conventions, you can avoid common errors, typos, or inconsistencies that could cause new bugs.
If you believe me if someone really follows coding standards and convention and principles of clean code and architecture then there is almost nil possibility to add bugs and that would be the ideal way to write code, that will help the devs to identify by just looking at the code what the code does. I believe coding is a skill of converting plain English to code
Using version control and branches can help you avoid introducing new bugs by isolating your bug fixes from the main codebase and allowing you to test and review them before merging them. You can use version control tools like Git or SVN to create branches for each bug fix, and then use pull requests or merge requests to submit them for approval and integration. By using version control and branches, you can avoid conflicts, errors, or unwanted changes that could affect the stability and functionality of your software.
Also you can use branches to identify exactly when and where the issue introduced to the code by going backwards throughout the history of the branch you can do that by put your hands exactly on the painful commit and start you fix from there.
Version control and branching is vital to prevent bugs from happening, but sometimes bugs can still go through due to differences in configurations in testing or development and production environments. One way to reduce this, as well as to speed up the time it takes for QA to perform testing, is to integrate your version control to build Preview apps that closely mimic production settings. This is particularly useful when local testing involves spinning up several microservices. This way, testing becomes more time efficient.
Refactoring is the process of improving the design, structure, or quality of your code without changing its behavior. Refactoring can help you fix bugs, reduce complexity, enhance readability, and optimize performance. However, refactoring can also introduce new bugs if you do not do it carefully and incrementally. You should refactor your code only when you have a clear goal, a good understanding of the code, and a reliable set of tests. You should also refactor your code in small and manageable steps, and test each step thoroughly.
Refactoring will be done mostly on a poor-quality code where the interactions between the layers or modules are usually tightly coupled. So, the person should have a very clear goal and great understanding of the code to breakdown the interactions into a sophisticated design architecture without introducing the bugs. Always refactor the code with great care, small increments, and test at each step to eliminate the bug introductions. Make a practice to prepare a test case with the inputs and expected results for each code modification which can help to avoid the introduction of new bugs.
Finally, one of the best ways to avoid introducing new bugs is to learn from your mistakes and prevent them from happening again. You can use bug tracking tools, feedback systems, root cause analysis, and post-mortems to document, analyze, and learn from the bugs that you fix. By learning from your mistakes, you can identify the patterns, causes, and solutions of the bugs, and apply them to your future bug fixes and software development.
One thing I've found helpful is understanding why the bug got introduced at first. It could be misunderstanding the requirement or missed test case or test setup issue etc. By figuring out where the flaw was really helpful to prevent them from happening again.
Always follow the software development process that can be Waterfall or Agile etc. Being a developer, we mainly focus on implementation of the functionality rather than process. Most of the processes force us to follow code reviews, code walkthroughs and testing methods. Which all helps to find the potential bugs early in the development process and avoids them turning into bugs later.