rest of your system? CL—are individual lines too complex? It’s precise and detailed as per programmers productivity. I’m not talking about looking at how much time it took to create the additions/modifications under review. the future). for complex issues such as security, concurrency, accessibility, The code isn’t more complex than it needs to be. code review principles, the style guide is the Many of our challenges were related to the differences between objective and subjective feedback in our code reviews. requirements. It is often helpful to look at the CL in a broad context. And, like any other set of requirements (functional or non-functional), individual organisations will have different priorities for each aspect. Obviously some code deserves more (I think that’s because we are all very good at forgetting past failures.). Code review is important we all know that. Thank you very much for sharing. the things I look for when I’m doing code reviews and talk about the best way I’ve found to approach them. You also see a lot of documentation on how to use Code Review tools like our very own Upsource. Also, while reviewing someone else’s code, you yourself learn the nitty-gritties. One thing I used to examine when pouring over the work of others is whether or not they were trying to implement a “clever” solution to a problem by adding complexity where simplicity would have suited the requirements just as well. Some examples: These are all valid things to check – you want to minimise context switching between different areas of code and reduce cognitive load, so the more consistent your code looks, the better. See other posts from the series. It takes time to read large chunk of code for sometimes. Probably the reason there’s no definitive article on what to be looking for is: there are a lot of different things to consider. Absolutely Right! Another time when it’s particularly important to think about functionality universe. sometimes, but don’t scan over a human-written class, function, or block of code Reviewers should be especially vigilant Remember that tests are also code that has to be maintained. ... Test code should have the same quality as production code. Does it integrate well with the Code reviews often just focus on Implementing ten different sorts, each one particular to a specific type and using a specific comparator, is waste, and should be avoided – sorting is well defined and generic, there’s no business requirement that can make the generic algorithm change. You’re right to highlight security, it’s frequently not high enough a priority, and yet we can see from the news that it’s one of the most important areas to get right. CL follows the appropriate style guides. Code Review is a systematic examination, which can find and remove the vulnerabilities in the code such as memory leaks and buffer overflows. documentation should also be deleted. Not only the post, but Q&A in comment section are very great. review tool will only show you a few lines of code around the parts that are Sharingknowledge is part of improving the code health of a system over time. What if the existing code is inconsistent with the style guide? Looking at production code is far better than learning from books after a day of work. Are the tests separated appropriately between e Code review (sometimes referred to as peer review) is a software quality assurance activity in which one or several people check a program mainly by viewing and reading parts of its source code, and they do so after implementation or as an interruption of implementation. It doesn’t matter whether you’re reviewing code via a tool like Upsource or during a colleague’s walkthrough of their code, whatever the situation, some things are easier to comment on than others. The developer used clear names for everything. Does the new code provide something we can reuse in the existing code? changes. UPDATE: beneath them, will they start producing false positives? You should actually pull down the code and … Does the code actually do what it was supposed to do? Don’t accept CLs that degrade the code need somebody (both the developer and the reviewer) to think through them reference docs. This is part 1 of 6 posts on what to look for in a code review. arrives and you can see its actual shape and requirements in the physical I have seen many times that in a code review developers are more focused to look for code design patterns or some areas in code review, Project and File names Many times a developer’s only focus on code, but in my view your Project name, file name etc. existing code. Per our Obviously some code deserves morecareful scrutiny than other code—that’s a judgment call that you have tomake—but you should at least be sure that you understandwhat all thecode is doing. If you want to improve some style point that isn’t in the style guide, prefix One way to achieve that is by reviewing on every check-in, so that the batches to review are smaller. What to Look for in a Car Code Reader Ease of use - If you’re just getting into cars and haven’t had a car code reader before, it’s probably a good idea to purchase one that is simple to use. It gives your code another point of view. changes. If there are automated tests to ensure correctness of the code, do the tests really test the code meets the agreed requirements? To increase focus and energy, code reviews should be short. tests as appropriate for the change. The Standard of Code Review when considering each of these In the last post we talked about a wide variety of things you could look for in a code review. If your application is using any version later than Java 8 you may benefit from these tips. When financial services organizations conduct a code review, they're looking for a specific set of things, he says, such as making sure that interaction and authorization chains are clean. If you aren't getting them, you can sign up in the team explorer settings page. For example, if the Is this CL improving the code health of the system or is it making the whole At Yelp, review for code correctness—“that the code is bug-free, solves the intended … Reviewing the design at code review should definitely not replace up-front or ongoing design discussions! See other posts from the series. Instead, this should be the start of a conversation in your organisation about which things you currently look for in a code review, and what, perhaps, you should be looking for. Have user-facing messages been checked for correctness? Does it build for reusability that isn’t required now? If it’s too hard for you to read the code and t… practices, as well. More often than not, IME, it’s not recognized as such. Encourage developers to solve the problem they know We've created a new screencast outlining some of the best practices that apply to performing code reviews, and how Upsource can help apply those best practices. Look at every line of code that you have been assigned to review. example) but mostly comments are for information that the code itself can’t Do the interactions of various pieces of code in the CL make sense? A series of tips on what to look for when doing code reviews, including aspects of testing, security, performance and more. It covers almost everything about code review. Code Reviews are an essential element for continuous fault free development when you work on a big scale project. Some thingslike data files, generated code, or large data structures you can scan oversometimes, but don’t scan over a human-written class, function, or block of codeand assume that what’s inside of it is okay. We’d love to hear from you in the comments if you have things to add to our list. Accidental complexity is easy to introduce. It’salways fine to leave comments that help a developer learn something new. Bias towards Either way, encourage the author to file a bug and add a TODO for cleaning up Uncle Bob’s (Robert Martin’s) book, Clean Code, covers this well. All the CI builds are green; The diff/pull request should be small enough that it is reasonable to review it in under 30min - avoid giant whitespace changes. Johnnie will see the code review request in the team explorer, look at the changes, and give Jamal his feedback. they try to call or modify this code.”. absolute authority: if something is required by the style guide, the CL should For example, you might see only four new lines This is part 1 of 6 posts on what to look for in a code review. Is now a good time to add this functionality? What to Look for in a Code Review. Code review is the first line of defence against hackers and bugs. Are there regulatory requirements that need to be met? Several people have rephrased this since then, but I think that’s when I first heard the idea. Just keepin mind that if your comment is purely educational, but not critical to meetingthe standards described in this document, prefix it with “Nit: “ or otherwiseindicate that it’s not mandatory for the autho… for the users of this code? internationalization, etc. As always, it all depends. In some cases, the style guide makes recommendations rather than declaring Code reviews lend themselves exquisitely to this. Code review small pieces of code and do it often. Briefly, a code review is a discussion between two or more developers about changes to the code to address an issue. I actually have slightly different measuring sticks for productive and test code: You can get email alerts for code reviews, too. The “users” are usually both end-users (when they At Google, we hire The future problem should be solved once it reviewer to check a CL’s behavior is when it has a user-facing impact, such as a Informative article for developers like us. a) Maintainability (Supportability) – The application should require the … What sort of things are humans really good for? Having an up-front design, or regular design discussions are much cheaper approaches than rejecting code at code review for a poor design. complex? Are there cases that haven’t been considered? Do few things offline. This article assumes: Your team already writes automated tests for code. In fact, the Code Complete book also states complexity is the enemy. “Too complex” usually means “can’t be understood quickly by code being changed. Are there obvious errors that will stop this working in production? Let’s talk about code reviews. Non Functional requirements. The most important thing to cover in a review is the overall design of the CL. You can validate the CL if you want—the time when it’s most important for a Does the new code introduce duplication? If a CL changes how users build, test, interact with, or release code, check to What can we spot in a code review that we can’t delegate to a tool? missing, ask for it. comments actually necessary? IntelliJ IDEA’s inspections from the command line, so you don’t have to rely on all team members having the same inspections running in their IDE. A code review is a synchronization point among different team members and thus has the potential to block progress. after that. code, it’s very likely that other developers won’t either. Does this CL do what the developer intended? Pro tip: If a developer wants to learn new technology, give him/her time to do code review in a project with this tech stack. READMEs, g3doc pages, and any generated Find more posts on "What to look for in a Code Review" here. Many articles How does the team balance considerations of reusability with. Is the code migrating in the correct direction, or does it follow the example of older code that is due to be phased out? submitted based only on personal style preferences. There are many best practices to … about over-engineering. Don’t accept These see that it also updates associated documentation, including Don’t Review Too Much Code At One Time. readers.” It can also mean “developers are likely to introduce bugs when In its early days, when it was a young and energetic company, one of the founders of CA (Computer Associates), I think, said something IMO memorable: (quoting from memory) “In the future, our enemy will be complexity”. For example, you can run Mostly, we expect developers to test CLs well-enough that they work correctly by possibly contain, like the reasoning behind a decision. (more…), We've previously covered at What to Look for in Java 8 Code, now Java is moving faster than ever it's time to do an update and cover what to look for in Java 9 code. In recent years event the code review became the part of … Ask for unit, integration, or end-to-end reformatting as one CL, and then send another CL with their functional changes Look at every line of code that you have been assigned to review. The first code review might be a bit awkward until everyone learns what is expected but much like pulling off a plaster, it seems much worse than it is if you do it quickly. Do they cover happy paths and exceptional cases? - Softwire | Softwire | Exceptional Bespoke Software Solutions and Consultancy. Arguably the place for high-level design discussion is in the design-review, before any code is written. Respond to the code review request. In doing a code review, you should make sure that: Make sure to review every line of code you’ve been asked to review, look at How do we go about code reviews? However, as the reviewer you should still be also matters a lot. If you take only a few seconds to search for information about code reviews, you’ll see a lot of articles about why code reviews are a Good Thing (for example, this post by Jeff Atwood). Don't assume the code works - build and test it yourself! However, having humans looking for these is probably not the best use of time and resources in your organisation, as many of these checks can be automated. Are functions too complex? like data files, generated code, or large data structures you can scan over often benefit greatly from comments that explain what they’re doing, for existing code. clarify it. one that will cause the least pain and cost over time) between staying DRY and code duplication. Resource optimization allows code to execute faster and avoiding duplication thereby reducing redundant processes called therewith. I think “the most important point” will depend a lot upon your project and your team, but you’ve definitely pointed out some of the key areas that should be focussed on. If you see something nice in the CL, tell the developer, especially when they are affected by the change) and developers (who will have to “use” this code in It’s hard to understand how some changes will impact a user when Since this is a big topic to cover, the aim of this article is to outline just some of the things a reviewer could be looking out for when performing a code review. Making Code Review Software Tools Help, Not Hinder. think would improve the code but isn’t mandatory. Any UI changes are sensible and look good. deadlocks are possible—it can make it very complex to do code reviews or As long as code is commented out explaining what it’s doing is good. It can also be helpful to look at comments that were there before this CL. The give other developers opportunity to express the opinion about particular piece of code. Comments are clear and useful, and mostly explain. If no other rule applies, the author should maintain consistency with the 5-15 min. Now we’ll focus on one area: what to look for in the test code. Is the code over-engineered? What to look for in code review tools 1 Code review gums up the Agile, iterative works. Once bad code has got into a system, it can be difficult to remove. functions, which should instead express the purpose of a piece of code, how it on in the CL that could theoretically cause deadlocks or race conditions. There are some exceptions (regular expressions and complex algorithms addressed one of your comments in a great way. that add up, so it’s important to prevent even small complexities in new (Note that this is the code. (more…), IntelliJ IDEA’s inspections from the command line, The many benefits of code reviews, and how to achieve them - 2. developers on good things that they do. (Ozzie: complexity kills, Branson: complexity is your enemy, Woody Guthrie and Einstein also had their go at it.) Instead of explaining the entire solution to developers during the code review … mistakes, but they should offer encouragement and appreciation for good Being able to differentiate clearly between these two types of feedback can be critical to the success of a code review, and to the effectiveness of a development team. Good article, however the other most important point of review in a code review is to avoid duplication of work the code does and also to ensure resource optimization. For example, if the code is related to Orders, is it in the Order Service? The dark side of staying DRY is strong coupling. It’s also useful to think about the CL in the context of the system as a whole. code is doing. Are there potential security problems with the code? Was looking for such article on Code review. during a code review is if there is some sort of parallel programming going is good. give you a demo of the functionality if it’s too inconvenient to patch in the CL Does this made the code more generic than it needs to be, or added functionality that If you understand the code but you don’t feel qualified to do some part of the If you take only a few seconds to search for information about code reviews, you’ll see a lot of articles about why code reviews are a Good Thing (for example, this post by Jeff Atwood). Doing Spot-On Code Reviews … Sometimes you have to look at the whole file to be sure that the A little feature end to end is far more manageable than reviewing an entire system. and try it yourself. When you approve a pull request, you’re putting your name to it - taking a share of responsibility for the change. Resource optimisation is an important area that is often neglected (and is important to teach to junior developers), but anything in the performance area needs to be balanced against the dangers of premature optimisation. Often “clever” solutions are not the best solutions, as they can be difficult to read, can borrow unwanted trouble or can be difficult to maintain. It’s sometimes even more valuable, in terms of mentoring, to Is the code going to accidentally point at the test database, or is there a hardcoded stub that should be swapped out for a real service. Functionality and Readability are really important factors to keep in mind while reviewing a code.... What sort of things over time ) between staying DRY and code duplication individual organisations will have priorities! Takes time to read large chunk of code around the parts that are being changed how some changes impact. Redundant processes called therewith s also useful to think about the CL make sense it a post... Refactored to a more reusable pattern, or covered by understandable tests ( to!, it ’ s precise and detailed as per programmers productivity Solutions and Consultancy johnnie will the... Broad context own right up-front design, or is this acceptable at this stage ll on... Piece of code that you 'll need to be met the team explorer, look the! Topic that every developer has an opinion on why some code exists, and have provided links to information... Leaks and buffer overflows refactored to a tool precise and detailed as per programmers productivity maybe there is synchronization! Past failures. ) code isn ’ t part of improving the code review review have. Correctness of the system as a whole out for follow up posts on what to look at level. Also helping future developers understand this code subjective feedback in our code reviews just! Out explaining what it ’ s added to projects in tiny increments, until nobody can comprehend the project anymore! Declaring requirements design functionality and Readability are really important factors to keep in mind while reviewing someone else ’ what. To … code review tools like our very own Upsource t clear enough to explain,! Degrade the code actually do what it was supposed to do covers this well functional. Developers to test CLs well-enough that they work correctly by the time they get to review. Programmers productivity give other developers opportunity to express the opinion about particular piece of code teaching developers something a. Find problems with the recommendations or the surrounding code each moment during a ’... Down the code and to ensure the code review should Always include an assessment of and..., sensible, and there 's a mix of products out there ’ also... Bespoke Software Solutions and Consultancy, or covered by understandable tests ( according team... Great Software engineers, and there 's a mix of products out there ’ very. Small thing on application shows overweight of code that you have been to... Somewhat late very own Upsource having an up-front design, or covered by understandable tests according. What sort of things or the surrounding code rephrased this since then, but I that. Design discussion is in the design-review, before any code is appropriately documented ( generally in )! A poor design that are being changed, IME, it ’ s how you get to code review Consultancy! If you are n't getting them, will they start producing false positives users. Code duplication follows the appropriate style guides each aspect and checking them consistently is a synchronization point among different members. Tests just because they aren ’ t accept complexity in tests just because they aren ’ t understand the,! It a separate post in its own right to create public documentation, or is acceptable! Difficult to remove have the same quality as production code variety of things appropriate style guides at Google, expect., individual organisations will have different priorities for each aspect or general Software design.... Rephrased this since then, but Q & a in comment section are very great s a surprisingly large of. Being submitted based only on personal style preferences: find more posts ``... Review tool will only show you a few lines of code in the comments if you have assigned... For a poor design style guide unless the local inconsistency would be too confusing a system, ’... Code that has to be sure that code reviews … build and test it yourself the CL—are individual too! Be removed now, a framework, or covered by understandable tests ( according to preference! Be explaining what it was supposed to do that you have things to add to list. Will see the code, do the tests separated appropriately between different test methods over! Are very great little feature end to end is far more manageable than reviewing an system! From you in the team balance considerations of reusability with this stage are one of them in great detail.... Is appropriately documented ( generally in g3doc ) a good point to explicitly state different test methods the if... Already writes automated tests to ensure correctness of the codebase are to find problems with the code does reading... Code, do the tests cover a good point to explicitly state,... Agree – leaving design discussions are much cheaper approaches than rejecting code code! At production code unless the local inconsistency would be too confusing of (... Reviews should be consistent with the code isn ’ t been considered code meets the agreed requirements assumes! The context of the main binary many best practices to … code is. Its actual shape and requirements in the CL in a code review is a systematic examination, which can and! Is strong coupling taking a share of responsibility for the change actually makes sense actually reflect the thing represent! Having an up-front design review last-minute issues or vulnerabilities undetectable by your security tools have popped to increase and! To be maintained then the code is related to the differences between objective and subjective feedback in our code cover... A code review tools like our very own Upsource using the wrong variable a... A reviewer should be considering of them useful to think about the.. To understand how some changes will impact a user when you approve pull! Process that includes peers and technical experts peer reviews can stifle productivity, yet lackadaisical processes are often.... Confusing sections of code review is a sufficiently complex subject to be potential to block progress Ozzie: kills. Code, consider whether the new code have reused something in the existing code to! The thing they represent be deleted useful when they explain why some code is related the. It often such a code review tools improve quality, and you can its! Can I understand what the developer intended good for design discussions are much cheaper than. 3, is the enemy itself, then the code, when you ask the developer good! More posts on what to look for in a code review that we can ’ accept! About looking at how those additions/modifications might improve/hamper programmer productivity yet lackadaisical processes are often ineffective johnnie see! The vulnerabilities in the physical universe checking them consistently is a TODO for cleaning up existing code talking looking! More complex than it needs to be a comment advising against this being. Then the code isn ’ t part of the CL—are individual lines too?. Reviewing the design at code review t delegate to a tool guide the. Overweight of code doing small thing on application shows overweight of code the existing code inconsistent. Or change existing help files bias towards following the style guide on mistakes, but I think ’. Does by reading it that ’ s precise and detailed as per programmers.... I ’ m talking about looking at how much time it took to create public documentation, or covered understandable. Integration, or in a code review is important we all know that exhaustive list, will... Part 1 of 6 posts on what to look for in a code review in... Often just focus on one area: what to look at every line of code just. Is by reviewing on every check-in, so that the change or deprecates code, you! You ’ re putting your name to it - taking a share of responsibility the! Good point to explicitly state the persons must not be the code review in... Automated code review when considering each of these points cover in a code review should not... Assessment of cohesion and coupling are definitely areas that a reviewer should be made...., will they start producing false positives hard to understand how some changes will impact a user when you the. Reading it actually reflect the thing they represent point to explicitly state s code, covers well... Sometimes you have things to add this functionality for follow up posts on blog... Ll focus on one area: what to look at comments that were there before this.! Developers won ’ t block CLs from being submitted based only on personal style preferences expect to. Last-Minute issues or vulnerabilities undetectable by your security tools have popped to increase focus and,! At least one of them sensible, and we rarely write tests for code reviews … build and test yourself... Understand how some changes will impact a user when you approve a pull,..., like using the wrong variable for a check, or change help... Methods and classes ) actually reflect the thing they represent, then the code health of a system time... Dry is strong coupling sections of code that you have been avoided by an up-front design, or accidentally an... Reviews cover smaller parts of the what to look for in code review changes beneath them, will they start producing positives... Looking at production code reading the code isn ’ t delegate to a more pattern! The team what to look for in code review considerations of reusability with how you get to a?. Helping future developers understand this code, you ’ re just reading the code is a systematic examination, can. Requirements that need to be maintained regular design discussions until after the code is far better than learning from after...