The biggest rule is that the point of code review is to find problems in code before it gets committed - what you're looking for is correctness.
The most common mistake in code review - the mistake that everyone makes when they're new to it - is judging code by whether it's what the reviewer would have written.
Remember that there are many ways to solve a problem.
Advice
What you're looking for is correctness.
Programming decisions are a matter of opinion. Reviewers and developers should seek to understand each other’s perspective but shouldn’t get into a philosophical debate.
Be humble.
Don’t be a prick. :-)
“I didn’t see where these variables were initialized”.
“What do you think about Standard DRY and if it’s applies here?”,
“I don’t understand why this is a global variable “
Make sure you have coding standards in place.
Coding standards are shared set of guidelines in an organization with buy-in from everyone. If you don’t have coding standards, then don’t let the discussion turn into a pissing contest over coding styles (opening braces ‘{‘ on the same line or the next!) If you run into a situation like that, take the discussion offline to your coding standards forum.
One of the goals of code reviews is to create ‘maintainable’ software.
Learn to communicate well.
You must be able to clearly express your ideas and reasons.
Authors should annotate source code before the review.
Authors should annotate code, what is the problem and goal, design and solution implementation, before the review occurs, because annotations guide the reviewer through the changes, showing which files to look at first and defending the reason behind each code modification. Annotations should be directed at other reviewers to ease the process and provide more depth in context. As an added benefit, the author will often find additional errors before the peer review even begins. More bugs found prior to peer review will yield in lower defect density because fewer bugs exist overall.
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Effective code reviews require a healthy culture that values quality and excellence. Code reviews will not give you the desired results if the team doesn’t believe in delivering high-quality products. You need a positive culture in which people are engaged – one that thrives on constructive criticism and allows the best ideas to win.
Peer code review can be efficient and effective while fostering open communication and knowledge-share between teammates.
