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Manual vs. Automated Code Reviews? Decoding the Great Debate | Pullflow Blog

Manual vs. Automated Code Reviews? Decoding the Great Debate

Striking the right chord between human insights and automated precision for superior code reviews.
Rabia Ahmed
Rabia Ahmed - Tue Jun 06 2023
Manual vs. Automated Code Reviews? Decoding the Great Debate


  • Code reviews are essential for ensuring code quality, maintainability, and security.
  • Manual and automated code reviews each have their merits.
  • Automation saves time but may miss issues related to code quality.
  • Automated reviews are scalable, enforce coding standards, and handle routine tasks efficiently.
  • Manual reviews offer insights into overall code quality and address false positives/negatives.
  • Manual reviewers provide clear suggestions for corrective actions and prioritize risks.
  • Code reviews impact collaboration, bug detection, code style, developer confidence, and a quality mindset.
  • The hybrid approach, combining automation and manual reviews, strikes the perfect balance.
  • Both manual and automated code reviews are valuable, fostering a culture of excellence in software development.

Code reviews. Ah, the joy and dread that they bring to every software developer’s life. It’s a process that can evoke mixed emotions—excitement for the opportunity to showcase your work and receive valuable feedback, and trepidation over the possibility of having your code scrutinized and critiqued. But whether we love them or hate them, there’s no denying their importance in ensuring the quality, maintainability, and security of our codebases.

In the world of code reviews, two methods dominate the landscape: manual and automated. Each has its own merits, limitations, and fanatical supporters. But which method truly reigns supreme? Let’s delve into the depths of the code review universe and explore the science behind these two approaches, with a sprinkle of personal anecdotes and a touch of humor along the way.

The Allure of Automation

A lot of times nowadays, I hear about automation. We want to automate everything—reviews, tests, deployments, you name it. It’s like a magical elixir that promises to cut down costs and make the programmer’s life a bit easier. And who can blame us? After all, the ultimate goal is to work smarter, not harder. But hold on a minute, let’s not get ahead of ourselves.

Automation is undoubtedly a friend in our programming life. It saves us time by automating repetitive tasks like code formatting and styling. Automated tests, if done correctly, help us quickly spot if any changes we make break something else in the codebase. But here’s the kicker—even the best tests can spot breaking changes but won’t ensure clean code.

Why? Because quality should always come first. No matter how many tests you automate, bad code will eventually fail. It might not fail due to bugs, but rather for reasons like poor readability, maintainability, usability, extensibility, security, or performance issues. And these are the defects that we need to address in our quest for high-quality software.

Quality should always be the priority. Even with automated tests, code can still have issues related to readability, maintainability, usability, extensibility, security, or performance. These are the defects that manual code reviews address in the pursuit of high-quality software.

The Benefits of Automated Reviews

While manual code reviews offer unique advantages, automated reviews also have their merits. Here are some points to consider:

  1. Scalability: Automated tools are ideal for large codebases or projects with frequent code changes. They can efficiently scan the entire code and provide feedback consistently and quickly.
  2. Rule enforcement: Automated code analysis tools are excellent for enforcing coding standards, style guidelines, and best practices. They can catch common mistakes and ensure adherence to a set of predefined rules.
  3. Efficiency: Automated reviews can handle mundane tasks, such as checking for syntax errors, unused variables, or potential performance bottlenecks. By automating these routine checks, developers can focus their attention on more complex issues during manual reviews.
  4. Consistency: Automated tools apply the same rules consistently across the codebase, reducing the chances of human error or oversight. This helps maintain a uniform coding style and can prevent certain types of issues from slipping through the cracks.

The Case for Manual Code Reviews

Certain aspects of code reviews can indeed be automated, especially when it comes to static code analysis. Tools can help us find performance issues or violations of coding standards. But even with all the automation in the world, we should not neglect the power of manual code reviews. Why? Because there are things that only the human touch can uncover.

Imagine this scenario: You come across a long method in the codebase. Automation might raise a flag, signaling a potential issue, but it can’t provide the context or insight needed to understand if the code is genuinely problematic or if it’s just doing its job. That’s where a human reviewer steps in. They can examine the code, understand the intentions behind it, and determine if there’s a need for refactoring or if it’s perfectly fine as it is.

The Human Touch: Harnessing the Superpowers of Manual Code Reviews

Manual reviews performed by experts bring a whole range of benefits that automated tools simply can’t match. Let’s explore some of these superpowers:

Superpower #1: Better Insights into Overall Code Quality

Manual code reviews offer a unique advantage by providing reviewers with a deeper understanding of the software’s overall quality. These reviews go beyond the surface-level technical checks and delve into factors such as code readability, modularity, and future extensibility. This holistic perspective allows reviewers to provide valuable insights and suggestions for improving the codebase’s overall quality.

One memorable code review session comes to mind, where we gathered as a team to discuss a particularly complex piece of code. While automated tools like SonarQube and ESLint flagged some potential issues, it was our reviewer, Bob, who truly shone during this review. As he meticulously examined the code, he spotted a design flaw that had the potential to cause severe performance bottlenecks in the long run. His keen eye and deep understanding of the system saved us from a potential disaster. It was a moment of code review brilliance that left a lasting impression on the entire team.

In situations like these, manual code reviews prove invaluable. They provide an opportunity for experienced reviewers to analyze the codebase from various angles, identifying areas for improvement that might have otherwise gone unnoticed. This comprehensive assessment helps raise the bar for code quality and ensures that the software is not only functional but also maintainable and scalable in the long term.

Superpower #2: Less False Positives/Negatives

Automated code analysis tools have undoubtedly made great strides in identifying potential issues in code. However, they are not infallible and can sometimes generate false positives or overlook certain types of defects. This is where manual code reviews shine, as human reviewers can exercise their judgment and context-specific knowledge to distinguish real issues from false alarms.

Let me illustrate this with some real-life coding tool examples:

  1. Static Code Analysis Tools such as SonarQube and ESLint are fantastic at scanning codebases and flagging potential issues. However, they may occasionally raise false positives. For instance, I recall a code review where a static analysis tool flagged a line of code as having a potential null pointer exception. Upon closer inspection, the code was part of a well-designed error-handling mechanism that explicitly handled null cases. The manual reviewer, having a deeper understanding of the code context, recognized the false positives and prevented unnecessary changes.

  2. Code formatting tools like Prettier and Black are widely used to ensure consistent and readable code styles. However, they can sometimes clash with certain code patterns or specific project requirements. In one code review instance, a formatting tool automatically reformatted a block of code, aligning it according to the default configuration. Unfortunately, the code had a specific layout optimized for performance reasons. The manual reviewer, with knowledge of the performance implications, recognized the importance of the code structure and decided not to modify it, overriding the automated tool’s suggestions.

These examples highlight how manual code reviews provide the necessary human touch to filter out false positives and negatives, ensuring that the codebase receives accurate and targeted feedback. The ability to leverage human judgment and contextual understanding is an irreplaceable superpower when it comes to code reviews. It allows us to distinguish between genuine issues and situations where automated tools may fall short, ultimately enhancing the quality of the codebase.

Superpower #3: Clear Suggestions for Corrective Actions

One of the distinguishing features of manual code reviews is the ability to provide clear and actionable suggestions for corrective actions. Automated tools might identify issues, but they often lack the context and ability to suggest specific improvements.

In a recent code review, our reviewer, Sarah, noticed a section of code that could be simplified using a more elegant design pattern. Rather than simply pointing out the problem, Sarah went the extra mile to explain the underlying principles and provided concrete examples of how the code could be refactored. Her insightful suggestions not only helped the developer rectify the immediate issue but also enhanced their understanding of software design principles.

This ability to offer specific and constructive feedback is a superpower skilled manual reviewers possess. By leveraging their expertise, they can guide developers towards writing cleaner, more efficient code and help foster a culture of continuous improvement within the team.

Superpower #4: Prioritizing and Defining Risks

Manual code reviews have a remarkable ability to help teams prioritize their efforts by identifying and defining the risks associated with defects found in the codebase. Reviewers bring their expertise to the table, carefully evaluating the severity and impact of each issue and offering guidance on which problems require immediate attention and which ones can be addressed at a later stage.

During a rigorous code review phase, our team encountered a range of defects, from minor bugs to potential security vulnerabilities. It was during this process that the true power of manual code reviews became evident. Our skilled reviewer, Alex, took the time to meticulously assess each issue, taking into account factors such as the frequency of occurrence, the severity of the impact, and the potential risks involved. With this thoughtful evaluation, Alex provided invaluable insights, clearly indicating which issues demanded immediate action and which ones could be handled in subsequent iterations.

The ability to prioritize and define risks is a crucial superpower of manual code reviews. By understanding the potential consequences of each defect, teams can strategically allocate their resources and focus on addressing the most critical issues first. This ensures that the software remains stable, secure, and reliable, safeguarding the overall success of the project.

With manual code reviews, teams gain a comprehensive understanding of the risks associated with their codebase. This insight empowers them to make informed decisions, ensuring that their development efforts are directed towards resolving the most impactful issues and mitigating potential risks.

Impact: The Ripple Effect of Code Reviews

Code reviews have an extraordinary impact on various aspects of software development, revolutionizing the way teams work and the quality of the code they produce. Let’s embark on a journey to uncover some unconventional and captivating ways in which code reviews create a tangible difference:

Impact #1: Supercharged Collaboration

Code reviews act as a catalyst for collaboration and camaraderie among developers. They bring the team together, providing a platform for knowledge exchange, shared learning, and spirited discussions. In the quest to craft impeccable code, developers engage in friendly banter, debating the merits of different approaches, and sparking creative solutions. Code reviews become a breeding ground for innovative thinking, where ideas clash and synthesize, ultimately leading to stronger teamwork and elevated code quality.

Impact #2: Bug Busting Bonanza

Code reviews are the ultimate bug busters! They form an early line of defense against the sneaky bugs and logic traps that lurk within the codebase. By bringing fresh pairs of eyes to the code, reviewers can uncover hidden flaws and potential pitfalls that might have eluded the original developer. It’s like having an army of code detectives, armed with magnifying glasses and Sherlock Holmes hats, meticulously combing through every line of code to ensure its integrity. Together, they wage a valiant battle against bugs, making the codebase a safer and more reliable place for everyone.

Impact #3: Style and Substance

Code reviews not only ensure the functionality of the code but also elevate its style and elegance. They champion the cause of readable and maintainable code, akin to a team of code fashionistas setting the latest trends. Reviewers can spot verbose and convoluted code like a fashion critic spotting a fashion faux pas on the runway. They gently nudge developers towards cleaner and more expressive code, advocating for best practices and industry standards. The result? A codebase that not only works flawlessly but also exudes beauty and grace.

Impact #4: Boosting Developer Confidence

Code reviews act as a confidence booster for developers. They provide an opportunity for developers to showcase their skills, receive recognition for their accomplishments, and grow their technical prowess. Positive feedback from reviewers serves as a validation of their hard work, boosting their confidence and motivation. Additionally, code reviews nurture a growth mindset within the team, where mistakes are seen as opportunities for improvement rather than sources of shame. Developers emerge from code reviews with a renewed sense of purpose and a desire to continuously sharpen their coding prowess.

Impact #5: Quality Mindset on Autopilot

Code reviews instill a quality mindset within the team, elevating the overall standard of the codebase. They create a culture where developers take pride in their craft, striving for excellence in every line of code they write. The habit of performing thorough code reviews becomes second nature, ingrained in the team’s DNA. It becomes unthinkable to submit code without subjecting it to the scrutiny of peers. With quality ingrained in the team’s consciousness, the codebase becomes a stronghold of reliability, robustness, and maintainability.

Impact #6: Tales of Heroic Bug Fixes

Code reviews create a treasure trove of legendary tales, filled with heroic bug fixes and incredible feats of debugging prowess. These anecdotes become part of the team’s folklore, shared during coffee breaks and celebrated during team outings. From the epic saga of “The Elusive Null Pointer” to the legendary “Merge Conflict of Doom,” code reviews provide ample material for stories that captivate and entertain. These tales not only bring the team closer but also serve as a reminder of the collective triumphs and challenges they have overcome.

Striking the Perfect Balance: A Hybrid Approach

Now that we’ve explored the virtues of both manual and automated code reviews, it’s time to reveal the ultimate secret sauce—the hybrid approach. The most effective code review processes often combine the strengths of both methods. By harnessing the power of automation to catch low-hanging fruit and leveraging manual reviews for in-depth analysis, teams can strike a balance that maximizes efficiency and code quality.

While manual code reviews offer human judgment and contextual understanding, a hybrid approach that combines automated and manual reviews can be highly effective. Here’s how they can complement each other:

  1. Automated pre-checks: Use automated tools to perform initial checks on code formatting, linting, and basic static analysis. This helps catch low-hanging fruit and reduces the manual reviewer’s workload.
  2. Manual analysis: Manual code reviews bring human insights and expertise to evaluate code quality comprehensively. Reviewers can identify complex issues, architectural considerations, and design patterns that automated tools may overlook.
  3. Collaboration: Code reviews provide an opportunity for collaboration and knowledge sharing among team members. Manual reviews encourage discussions, foster learning, and help disseminate best practices within the team.
  4. Continuous improvement: While automation can identify issues, manual reviews provide actionable suggestions for improvement. Skilled reviewers can guide developers towards cleaner, more efficient code and help them grow their technical skills.

Imagine a world where automated tools help with formatting, linting, and basic static analysis, freeing up valuable time for manual reviewers to focus on critical thinking, design patterns, and architectural considerations. It’s a harmonious dance between man and machine, each playing its part in creating exceptional software.

Conclusion: Manual vs. Automated Code Reviews?

Code reviews, whether manual or automated, are invaluable for software development. They help us uncover hidden bugs, improve code quality, foster collaboration, and promote continuous learning. While automation can streamline certain aspects of the process, the human touch and expertise of manual reviewers are indispensable for achieving truly outstanding results.

So, the next time you embark on a code review journey, embrace the art and science of it. Celebrate the insights, the collaboration, and the occasional moments of brilliance. Remember that code reviews are not just about finding defects; they are about shaping a culture of excellence and craftsmanship within the software development community.

Now, go forth and review code with a blend of automation, and human judgment. Your codebase—and your fellow developers—will thank you!

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