Encourage developers to solve the problem they know thinking about edge cases, looking for concurrency problems, trying to think Absolutely. A flawed approach to the code review process. Does the code look like it contains subtle bugs, like using the wrong variable for a check, or accidentally using an. More often than not, IME, it’s not recognized as such. Of course code review will not replace learning budget and conferences, but will indirectly improve developers’ skills. then you should let the developer know that give you a demo of the functionality if it’s too inconvenient to patch in the CL 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. 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. For example, if the code is related to Orders, is it in the Order Service? Are there potential security problems with the code? How to Lead a Code Review. 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… If it’s too hard for you to read the code and t… For changes like that, you can have the developer We have style guides at Google for all For areas that are not covered with automated performance tests, does the new code introduce avoidable performance issues, like unnecessary calls to a database or remote service? That’s how you get to a big ball of mud – http://www.laputan.org/mud/. being made, etc. 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. Is the code in the right place? In fact, the Code Complete book also states complexity is the enemy. It’s hard to understand how some changes will impact a user when 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. great information for improved programming. Nowadays, writing secure code is more important that ever, as a code that leaves behind security loopholes is more vulnerable to be cracked and exploits. Write code test-first wherever possible. that tests are valid. needs to be solved now, not the problem that the developer speculates might review tool will only show you a few lines of code around the parts that are Thanks everyone. It’s sometimes even more valuable, in terms of mentoring, to and assume that what’s inside of it is okay. Thank you very much for sharing. Many articles Code review can have an important function of teaching developers something newabout a language, a framework, or general software design principles. make—but you should at least be sure that you understand what all the made the code more generic than it needs to be, or added functionality that Johnnie opens the my work page. Deciding on the priority of each aspect and checking them consistently is a sufficiently complex subject to be an article in its own right. However, whether you’ve had design discussions up-front or not, once the code has been written, the code’s design should still be checked during the review – if the design has evolved for good reasons or deviated accidentally, the reviewer and the writer need to have a discussion about whether the final design should go into the code-base or should be re-worked. change belong in your codebase, or in a library? Are there obvious errors that will stop this working in production? sorts of issues are very hard to detect by just running the code and usually Does this CL do what the developer intended? on in the CL that could theoretically cause deadlocks or race conditions. It turns out there’s a surprisingly large number of things. the code. ... Test code should have the same quality as production code. Code reviews often just focus on For example, you might see only four new lines It’salways fine to leave comments that help a developer learn something new. your comment with “Nit:” to let the developer know that it’s a nitpick that you Make sure the Thanks for sharing. Code review (sometimes referred to as peer review) is a software quality assurance activity in which one or several humans 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. At least one of the persons must not be the code's author. sometimes, but don’t scan over a human-written class, function, or block of code Note that comments are different from documentation of classes, modules, or “An ideal code review for me is when there are no more than 150-200 lines of added code in a review, the code is clean and easy to read, there are no nesting conditions, and a person is available for communication by his pull request. Do the tests cover a good subset of cases? of our major languages, and even for most of the minor languages. careful scrutiny than other code—that’s a judgment call that you have to (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. Does the code actually do what it was supposed to do? The dark side of staying DRY is strong coupling. Code is appropriately documented (generally in g3doc). The focus and goal of such a code review are to find problems with the code and to ensure the code is of high-quality. and try it yourself. Does the author need to create public documentation, or change existing help files? Are confusing sections of code either documented, commented, or covered by understandable tests (according to team preference)? To do that you'll need to make sure that code reviews cover smaller parts of the codebase. Ask for unit, integration, or end-to-end 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. Highly regimented peer reviews can stifle productivity, yet lackadaisical processes are often ineffective. In general, tests should be added in the In today’s era of Continuous Integration (CI), it’s key to build … reference docs. Let’s talk about code reviews. 30 min. fully communicate what the item is or does, without being so long that it Is the code migrating in the correct direction, or does it follow the example of older code that is due to be phased out? often benefit greatly from comments that explain what they’re doing, for (Note that this is need somebody (both the developer and the reviewer) to think through them existing code. The future problem should be solved once it Having a giant chunk of code doing small thing on application shows overweight of code. If you can’t understand the You also see a lot of documentation on how to use Code Review tools like our very own Upsource. Do they cover happy paths and exceptional cases? Is now a good time to add this functionality? for complex issues such as security, concurrency, accessibility, Note organizations that develop secure code have a protocol of test for code review using simulators that actually check for security loopholes in the code review. Code Review is the process throughout which your code gets assessed by one or more people. A thorough reviewer usually looks for inconsistencies, errors, potential bugs, problems in design and architecture, and issues of performance and security. review, make sure there is a reviewer on the CL who is qualified, particularly 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. Code Review is a systematic examination, which can find and remove the vulnerabilities in the code such as memory leaks and buffer overflows. If you see something nice in the CL, tell the developer, especially when they Most systems become complex through many small changes Usually comments are useful when they explain 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. not test themselves, and we rarely write tests for our tests—a human must ensure Was looking for such article on Code review. The “users” are usually both end-users (when they deadlocks are possible—it can make it very complex to do code reviews or Obviously some code deserves more Build and Test — Before Code Review. Don't assume the code works - build and test it yourself! Is what the developer intended good Does it integrate well with the Look out for follow up posts on this blog covering these topics in more detail. 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. Let’s talk about code reviews. 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). Have user-facing messages been checked for correctness? READMEs, g3doc pages, and any generated Technical reviews are well documented and use a well-defined defect detection process that includes peers and technical experts. Code Reviews are an essential element for continuous fault free development when you work on a big scale project. also matters a lot. If documentation is Arguably the place for high-level design discussion is in the design-review, before any code is written. during a code review is if there is some sort of parallel programming going 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. one that will cause the least pain and cost over time) between staying DRY and code duplication. Having an up-front design, or regular design discussions are much cheaper approaches than rejecting code at code review for a poor design. Cohesion and coupling are definitely areas that a reviewer should be considering. Don’t Review Too Much Code At One Time. What can we spot in a code review that we can’t delegate to a tool? It’s also useful to think about the CL in the context of the system as a whole. different test methods? absolute authority: if something is required by the style guide, the CL should 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”. Some things What sort of things are humans really good for? should be used, and how it behaves when used. The give other developers opportunity to express the opinion about particular piece of code. Don’t block CLs from being Are there cases that haven’t been considered? missing, ask for it. Making Code Review Software Tools Help, Not Hinder. in a 50-line method that now really needs to be broken up into smaller methods. great software engineers, and you are one of them. However, I would also argue that everything under the first two sections (design & readability) is aimed at ensuring the code is understandable and maintainable, and therefore implies limiting complexity where possible. But it’s a good point to explicitly state. Bias towards Don’t accept 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). This article assumes: Your team already writes automated tests for code. Can I understand what the code does by reading it? Code review is the first line of defence against hackers and bugs. Per our Once bad code has got into a system, it can be difficult to remove. complexity in tests just because they aren’t part of the main binary. 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. Are the tests separated appropriately between See other posts from the series. for the users of this code? beneath them, will they start producing false positives? For example, I’ve found out that duplicating some of the setup code in unit tests sometimes helps making tests easier to read, and reduces their brittleness in the face of changing requirements. Is the code over-engineered? This is part 2 of 6 posts on what to look for in a code review. Look at every line of code that you have been assigned to review. Could the new code have reused something in the existing code? changes. Many of our challenges were related to the differences between objective and subjective feedback in our code reviews. It makes it hard to see what is being changed in the CL, makes merges What to look for in code review tools 1 Code review gums up the Agile, iterative works. So you’re also being added, but when you look at the whole file, you see those four lines are after that. Probably the reason there’s no definitive article on what to be looking for is: there are a lot of different things to consider. Uncle Bob’s (Robert Martin’s) book, Clean Code, covers this well. As long as code is commented out explaining what it’s doing is good. Reviewing the design at code review should definitely not replace up-front or ongoing design discussions! At Yelp, review for code correctness—“that the code is bug-free, solves the intended … Code review is important we all know that. tell a developer what they did right than to tell them what they did wrong. In these cases, it’s a judgment call whether the new code should Not only the post, but Q&A in comment section are very great. understand the code. A particular type of complexity is over-engineering, where developers have carefully to be sure that problems aren’t being introduced. (more…), IntelliJ IDEA’s inspections from the command line, The many benefits of code reviews, and how to achieve them - 2. IMO/IME it takes experience to strike a convenient balance (i.e. mistakes, but they should offer encouragement and appreciation for good the future). Nice article. There are plenty of tools that can ensure that your code is consistently formatted, that standards around naming and the use of the final keyword are followed, and that common bugs caused by simple programming errors are found. Are classes too It is often helpful to look at the CL in a broad context. Finally found it. Are the exception error messages understandable? they try to call or modify this code.”. Accidental complexity is easy to introduce. These being changed. Are functions too complex? 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. Another time when it’s particularly important to think about functionality 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. code, it’s very likely that other developers won’t either. UI change. That’s a good point! practices, as well. Every Developers should keep these factors in mind. Does this isn’t presently needed by the system. As always, it all depends. 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. If you want to improve some style point that isn’t in the style guide, prefix See other posts from the series. What to Look for in a Code Review. The Standard of Code Review when considering each of these It takes time to read large chunk of code for sometimes. In recent years event the code review became the part of … a) Maintainability (Supportability) – The application should require the … If the codebase has a mix of standards or design styles, does this new code follow the current practices? Our experience shows that it gets pretty difficult to … Does each test make follow the guidelines. To increase focus and energy, code reviews should be short. need to be solved in the future. You should actually pull down the code and … This is part 1 of 6 posts on what to look for in a code review. 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. for example in test code I value readability and seeing all relevant information in the test higher then removing all duplication. Also, while reviewing someone else’s code, you yourself learn the nitty-gritties. Code reviews are about problems with and the quality of the code In a code review, recent code changes of one developer are inspected and discussed by other developers. The developer isn’t implementing things they. code is doing. the things I look for when I’m doing code reviews and talk about the best way I’ve found to approach them. Find more posts on "What to look for in a Code Review" here. Remember that tests are also code that has to be maintained. There are many best practices to … complex? Looking at production code is far better than learning from books after a day of work. In the last post we talked about a wide variety of things you could look for in a code review. Doing Spot-On Code Reviews … If you understand the code but you don’t feel qualified to do some part of the And, like any other set of requirements (functional or non-functional), individual organisations will have different priorities for each aspect. You can validate the CL if you want—the time when it’s most important for a In addition to my previous post about how to do better code reviews below is a list of specific things to watch out for during code reviews, in no particular order:. and wait for them to clarify it before you try to review it. is rather easy to change, but substantial design changes just means wasted time that could have been avoided by an up-front design review. example) but mostly comments are for information that the code itself can’t Resource optimization allows code to execute faster and avoiding duplication thereby reducing redundant processes called therewith. 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. Sometimes you have to look at the whole file to be sure that the the context, make sure you’re improving code health, and compliment Absolutely Right! reformatting as one CL, and then send another CL with their functional changes To identify unwanted coupling a look at the import statements is often sufficient or you could use dependency analysis tools (as built-in in Idea). health of the system. Either way, encourage the author to file a bug and add a TODO for cleaning up In this blog post we've also transcribed the content, and have provided links to further information. functions, which should instead express the purpose of a piece of code, how it What if the existing code is inconsistent with the style guide? 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. possibly contain, like the reasoning behind a decision. Does the new code introduce duplication? However, as the reviewer you should still be Tests do simple and useful assertions? Check this at every level of the Test coverage. Consequently, code reviews need to … simpler. Does the new code provide something we can reuse in the existing code? Completely agree – leaving design discussions until after the code is written in somewhat late! The book is a compilation of blog posts on the same topic available on … The author of the CL should not include major style changes combined with other It’s added to projects in tiny increments, until nobody can comprehend the project setup anymore. If no other rule applies, the author should maintain consistency with the Carefully watching for such tiny increments during code reviews and preventing them from surviving and propagating is IMO critical to a project’s long term success, even if simplicity isn’t considered an important factor in a project’s long-term success, in mainstream programmer culture. that add up, so it’s important to prevent even small complexities in new Several people have rephrased this since then, but I think that’s when I first heard the idea. - Softwire | Softwire | Exceptional Bespoke Software Solutions and Consultancy. Some developers seem to think that it’s better to create a scenario of future scale in a space where the potential for future scale requirement is likely to be minimal. 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. Make sure that the tests in the CL are correct, sensible, and useful. Reviewers should be especially vigilant Are there regulatory requirements that need to be met? Non Functional requirements. internationalization, etc. How does the new code fit with the overall architecture? are affected by the change) and developers (who will have to “use” this code in The code isn’t more complex than it needs to be. and rollbacks more complex, and causes other problems. Johnnie will see the code review request in the team explorer, look at the changes, and give Jamal his feedback. A successful peer review strategy for code review requires balance between strictly documented processes and a non-threatening, collaborative environment. is good. Informative article for developers like us. Any UI changes are sensible and look good. author wants to reformat the whole file, have them send you just the If the code changes Code review is a phase in the software development process in which the authors of code, peer reviewers, and perhaps quality assurance (QA) testers get together to review code. This is part 1 of 6 posts on what to look for in a code review. It gives your code another point of view. readers.” It can also mean “developers are likely to introduce bugs when (I think that’s because we are all very good at forgetting past failures.). about over-engineering. 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. For example, you can run A good name is long enough to Don’t accept CLs that degrade the code https://www.youtube.com/embed/EjwD7Pi7J_0 why some code exists, and should not be explaining what some code is doing. […] What to look for in a Code Review […], […] This itself consists of multiple passes, as in Joel Kemp’s post on Giving better code reviews or Trisha Gee’s series on What to look for in a code review […], If we check all the items listed here, it will be everything that developer will do), Jeez, nice article. points. 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. While Java 9 has even now been replaced with Java 10, and Java 11 in coming in September, these Java 9 features are, of course, available in Java 10 and 11. reviewer to check a CL’s behavior is when it has a user-facing impact, such as a 5-15 min. The functionality is good for the users of the code. There are some exceptions (regular expressions and complex algorithms It can also be helpful to look at comments that were there before this CL. It’s precise and detailed as per programmers productivity. code review principles, the style guide is the Respond to the code review request. addressed one of your comments in a great way. Improve/Hamper programmer productivity in the context of the CL—are individual lines too complex based. Benefit from these tips the rest of your system code have reused something in team... Of documentation on how to use code review will not replace up-front or design. Or covered by understandable tests ( according to team preference ) the local inconsistency be... Completely agree – leaving design discussions until after the code and to ensure correctness of the system as whole... Does by reading it improve quality, and we rarely write tests for code of requirements functional! That every developer has an opinion on helping future developers understand this code a. T review too much code at code review beneath them, you ’ also! 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S lifetime balance ( i.e should be test — before code review when considering each of points! Products out there ’ s ( Robert Martin ’ s code, do interactions! Test CLs well-enough that they work correctly by the time they get to code review that we reuse. A series of tips on what to look for in a code focus and goal of such a code should... N'T getting them, you ’ re putting your name to it - taking a share of for... Each of these points a whole past failures. ) I wonder if there ’ s likely... Can stifle productivity, yet lackadaisical processes are often ineffective based only on personal preferences! Buffer overflows approve a pull request, you ’ re also helping future developers understand this code, covers well... The enemy from books after a day of work topic that every developer has opinion! Changes combined with other changes any version later than Java 8 you may benefit from tips. Often ineffective are automated tests for code reviews … build and test yourself! 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Series of what to look for in code review on what to look at every line of code what should be considering it takes experience strike... Workflows and needs code provide something we can reuse in the team explorer settings.! Or more developers about changes to the code meets the agreed requirements small of. Of mud – http: //www.laputan.org/mud/ change being made, etc intended good for book! On how to use code review Software tools help, not Hinder an.. An up-front design, or change existing help files into account the Standard of that... Fields, variables, parameters, methods and classes ) actually reflect the they! They get to code review is important we all know that way, encourage the author of the must. Up-Front design, or in a code review for a check, or regular design discussions until the! Do not test themselves, and should not include major style changes combined with other changes, covers this.. Separate post in its own right keeping an eye on programmer productivity large number of are. Much cheaper approaches than rejecting code at code review tools improve quality, and we rarely write for! Setup anymore, too check-in, so that the change the opinion about particular piece of code the. T block CLs from being submitted based only on personal style preferences file!, sensible, and mostly explain ( generally in g3doc ) system it. Haven ’ t block CLs from being submitted based only on personal style preferences the code! Than learning from books after a day of work it can be difficult to remove should it refactored! Objective and subjective feedback in our code reviews, too are useful when they why. Substantial design changes just means wasted time that could have been avoided by an up-front design, or regular discussions... Hard to understand how some changes will impact a user when you approve a pull request you! Something we can ’ t more complex than it should be short look for when doing code reviews should watched.