The quick definition above contains a couple of subtle points. These smells mean that if you need to change something in one place in your code, you have to make many changes in other places too. 20. The term was popularised by Kent Beck on WardsWiki in the late 1990s. What about me? The key insight here is that if you have to add a comment to a line or a couple of lines of code you can probably refactor the code into a function which has the comment as the name.   You cannot paste images directly. Code comments are definitely not a "code smell". User account menu. Clarification comments are intended for anyone (including your future self) who may need to maintain, refactor, or extend your code.Often, a clarification comment is a code smell. Code Smell. Students usually consider comments to be good, but they don't always improve things. Two kinds of comments exist: JavaDoc-style comments (which encompasses JavaDoc, XMLDoc, RDoc, etc), which are designed to produce developer documentation at a high level (class and method names and what they … Here is a list of some of the most important smells. The idea behind comments seems pretty straightforward: we can add information about code that the code … It has a good example of a "WHY" comment as follows. Archived. Haha, I love coders and their views on coding life. All of these change at different speeds. Don’t just stop writing comments; they are better than nothing. I work at Rareloop as the lead developer, over in Southampton. User account menu. Clarity over Brevity in Method and Variable Names, http://www.scottraymond.net/2003/5/19/pace-layers/. Parallel Inheritance Hierarchies. Display as a link instead, × The majority of a programmer's time is spent reading code rather than writing code.   Pasted as rich text. Consider taking the comment and using it as the name of the function instead. Code smells indicate a deeper problem, but as the name suggests, they are sniffable or quick to spot. This is an example of self-documenting code. Computer Programming. I find this so often in mature projects. Instead of documenting WHY they are doing things a particular way, they instead put in the documentation WHAT the code is doing. What does that mean? If it is not possible to view the whole method on your 5" smartphone screen, consider breaking it up into several smaller methods, each doing one precise thing. In computer programming, a code smell is any characteristic in the source code of a program that possibly indicates a deeper problem. While each individual function might be quite self explanatory, it cannot convey the intent of a class as a whole. So not commenting on your code will create hard to read code for complex blocks for both you and your peers. What was missing was what I was grappling with. My first response was of course "well why is that not in the comments!?". These comments just added to the noise in the file, made the code not fit on one page, harder to read and did not tell me anything that the code was not already telling me. Powered by Invision Community. Quite often we try more than one approach when designing and implementing a piece of code, weighing various metrics/properties of the code to settle finally on the preferred solution. Log in sign up. Even the Hungarian notation as an extended version of commenting de-synchronizes eventually, because you tend to ignore the prefixes after a while. A fundamental property of good software is that it is easy to change it, which means that it is easy to understand the code. I think the smell was there before you wrote the comments. Press J to jump to the feed. Always test your comments against the golden rule of comments, and if it is explaining what is happening then delete that comment! The code is the best way to describe what the code is doing and we hope that someone trying to maintain the code is proficient in the language it is written in, so why all of the WHAT comments? So what are we to do, how do we know if comments are good or bad? --your team's principled developer. - Comments Code Smell I know you might be surprised now, and yes the comments is a code smell if they are used in the wrong way, so here are my tips: * Remove unnecessary comments. Most people will also tell you, that the biggest problem with comments is that they soon become outdated. Nobody should ever read a piece of your code and ask out loud "what were they thinking when they did this?". If the purpose is obvious and easily derivable from the identifiers, why create a second meta layer which needs extra maintenance and creates a dependency? Comments are of course not without a cost, and once written, they have to be updated if the code is updated. Well, I dunno. I would suggest the golden rule must be to test your comment by asking whether is it explaining WHY the code is done this way or if it is stating WHAT the code is doing. In such cases, comments are like a deodorant masking the smell of fishy code that could be improved. Bloaters are code, methods and classes that have increased to such gargantuan proportions that they are hard to work with. Comments, when misused, often indicate a code smell. This guide will help refactor poorly implemented Java if statements to make your code cleaner. Properly commented code … 1 Code Smell 01 - Anemic Models 2 Code Smell 02 - Constants and Magic Numbers... 47 more parts... 3 Code Smell 03 - Functions Are Too Long 4 Code Smell 04 - String Abusers 5 Code Smell 05 - Comment Abusers 6 Code Smell 06 - Too Clever Programmer 7 Code Smell 07 - Boolean Variables 8 Code Smell 08 - Long Chains Of Collaborations 9 Code Smell 09 - Dead Code 10 Code Smell 10 - Too … Please … Press J to jump to the feed. It is not necessarily a problem in itself and should be a hint at a possible problem. And with readable I mean to read it out loud in front of an audience (e.g. The vast majority of comments I ever see are unnecessary, and are frequently used to cover up obtuse code. Posted by 18 days ago. This blog has a number of great examples of how NOT to comment your code, and comical as the examples are the scary part is how often I actually see these kinds of comments in production code! Comments are usually created with the best of intentions, when the author realizes that his or her code isn’t intuitive or obvious. A code smell is a hint that something has gone wrong somewhere in your code. Overuse or poor use of if statements is a code smell. * Remove commented debugging var_dump, echo, ..etc. Is there not a more elegant way to do this which would not require comments to explain, where reading the code would make what it is doing obvious? Program development becomes much more complicated and expensive as a result. CODE SMELL/ BAD SMELL Types of Code Smell Comments Comments are not bad smell. Long methods make code hard to maintain and debug. Other code smell videos. The term was first coined by Kent Beck while helping me with my Refactoring book.   Your previous content has been restored. 793 votes, 614 comments. What you were thinking should be there in plain sight, documented in the comments. What every embedded programmer should know about ... /* don't use the global isFinite() because it returns true for null values */, Modular code and how to structure an embedded C project, #pragma config PWRTE = ON // Power-up Timer Enable bit->Power up timer disabled. Code Smell; Comments should not be located at the end of lines of code Code Smell; Lines should not end with trailing whitespaces Code Smell; Files should contain an empty newline at the end Code Smell; Long suffix "L" should be upper case Code Smell; Functions returns should not be invariant Analyze your code. Wenn ich wissen wollte, was in einer Methode oder einem Block passiert, würde ich den Code lesen. My name is Adam. The key insight here is that if you have to add a comment to a line or a couple of lines of code you can probably refactor the code into a function which has the comment as the name. Here, we push all our complex code down into private methods with descriptive names and don’t bother with comments about the implementation. 2.9m members in the programming community. As for the complex list comprehension, well, if you want to know exactly how that works, you should be able to find something in the specs that says describe "by_year_and_month" do…. * Don’t leave commented old code. As for the Interface, i.e. Comments == Code Smell I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. When you feel like writing a comment, first try to refactor so that the comment becomes superfluous. This in turn often means that an over-commented code doesn't have a good structure or the author doesn't understand the problem well enough to abstract it. If you find that you need to find the right person to maintain any piece of code in your system because "he knows what is going on in that code" or even worse "he is the only one that knows" this should be an indication that the documentation is incomplete and more often than not you will find that the comments in this code are explaining WHAT it is doing instead of the WHY's. Clear editor. Comments should give the reader a general overview of the problem and an abstract strategy what has to be done in a function. Hello. Although sometimes the project dictates code metrics, like a code to comment ratio that has to be satisfied. I asked a colleague and to my frustration his answer was that he remembered that there was some discussion about this part of the code and that it was done this way for a very good reason! Code smells can be easily detected with the help of tools. There is no need to write functions with many lines of code to make the compiling more efficient or save stack space, modern compilers will optimize that out again. I was musing over a piece of code this week trying to figure out why it was doing something that seemed to not make any sense at first glance. 793. Press question mark to learn the rest of the keyboard shortcuts . I quite like this Codemanship video, which shows how comments can be a code smell, and how we can use the comments to refactor our code to be more self-explanatory. KentBeck (with inspiration from the nose of MassimoArnoldi) seems to have coined the phrase in the "OnceAndOnlyOnce" page, where he also said that code "wants to be simple". Share and discover the latest news about the PHP ecosystem and its community. Author has named them a Sweet Smell When you feel the need to write comment,first try to re-factor the code so that any comment becomes superfluous. Good programmers therefore write code that is easy to understand. I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. For everything else, there’s self-documenting code and you can push all your complexity down into private methods which can be unreadable to humans and without comments as long as there are specs that express the intended behaviour. This video looks at when and how to use them to get the results you want. The comments in this part of the code were of absolutely no help, they were simply describing what the code was doing. Shotgun Surgery. But even when working alone all the time, in-code comments are a great tool to document classes and methods, give insights and write messages to future you and others. This belief typically comes from the fact that comments can become stale (out of date) and can be difficult to maintain. Apart from the difficulty of having to keep a lot of complex logic in mind whilst reading through a long method, it is usually a sign that the method has too many responsibilities. If you feel that a code fragment can’t be understood without comments, try to change the code structure in a way that makes comments unnecessary. We all agree that good code is code which is properly documented, referring to the right amount of comments, but there is a terrible trap here that programmers seem to fall in all of the time. If you have a line which only calls a function that means that the function is probably not named well enough to be obvious. Developing your "code nose" is something that happens early in your programming career, if it's going to happen at all. Is it a bug? Comments are often used as Deodorant to the bad smell. WHAT comments explaining the code itself can often be replaced by more expressive code. There is an excellent talk by Kevlin Henney about this on youtube. 4 min read. However, having good comments which explain why the code is doing something a certain way can (and usually is) important for maintenance. You should be documenting what was going on in your head when you were writing the code. When you comment your code you should be capturing that kind of context. Log In Sign Up. 20. Treat inline comments as code smells. Hungarian notation breaks the abstraction of having a variable name with unspecified underlying storage, so I think it is the worst way to leak implementation details! the public API, you should be documenting it with comments that feed into YARD, TomDoc or any other automatic documentation generating tools. Comments == Code Smell Posted by: Neal Ford on November 7, 2008. So most comments === code smell. Kent Beck recently wrote a piece called Naming From the Outside In in which he discusses a very interesting concept - that various parts of your system change at different speeds. Code smells are indicators that there might be something afoul in our code. Try to make your code self-documenting or intention-revealing. Comment: Comment and document your code often as you might also not remember that a complex piece or a variable++ had solved some problems in the past. I remember having conversations about comments being a code smell many times in the past. Comments == Code Smell. Only keep the WHY comments and make sure they are complete. Comments are code smells. Of late there have been numerous posts for and against comments in source code. A code smell is a characteristic of a piece of code that does not “feel right”. Determining what is and is not a code smell is subjective, and varies by language, developer, and development methodology. People who tell us that we should always be writing theoretically perfect code are not always people with a lot of experience of programming in real-world environments. WHY comments highlighting reasoning are valuable. The best smell is something easy to find but will lead to an interesting problem, like classes with data and no behavior. For example if we need a comment to explain what a block of code does; try Extract method,if …   Your link has been automatically embedded. Someone edited bit masks for a register, but forgot to update the comments. This frees the reader from the burden of having to comprehend the various maps, group_bys and so on that we resort to in order to massage our data into the expected format. I see a lot of projects with Doxygen comments in it, but the actual content of that documentation is rather unhelpful. In the above example, we hide away the complicated list comprehension behind a descriptive method name like by_year_and_month. × There's nothing wrong with codifying refactoring guidelines in a book. It tells you that your code is too complex. Encapsulating a partial solution not only brings structure to your code, it makes the function actually readable. In other words: extract and name. Here we have a clue as to how to write comments with a vastly reduced burden of maintainence. Code smell? Also, the cognitive load of reading a whole class in order to understand what it does can be greatly reduced by starting the class off with comments that convey the intent of the class. comments anti-patterns — Fishtoaster quelle 44. Paste as plain text instead, × I quite like this Codemanship video, which shows how comments can be a code smell, and how we can use the comments to refactor our code to be more self-explanatory. 20 votes, 76 comments. Two kinds of comments exist: JavaDoc-style comments (which encompasses JavaDoc, XMLDoc, RDoc, etc), which are designed to produce developer documentation at a high level (class and method names and what they do) In-line comments, generally scattered around … First, consider deleting the comment altogether, the code is already explaining what is being done after all. Next try to rename things or refactor it into a well-named method or fix the problem in some other way. August 18, 2019. I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. Ich werde jede Antwort, die "nein" sagt, positiv bewerten. Or Jeff Atwood’s post here. Is it a bugfix? On the anti side, we have for example DHH, whose recent post Clarity over Brevity in Method and Variable Names on the 37signals blog calls out comments as a code smell saying that the code should be self explanatory. Close. They cover the smell that was already there without actually fixing the problem, which is that your code is overcomplicated and confusing. Close. In other words, most comments are absolutely misused. I try to avoid comments, because they tend to de-synchronize with the actual code very easily. Over the last few years, I’ve learned a lot about software maintainability and one of these lessons is that comments are a code smell. Posted by 3 years ago. Divergent Change. Blocker SonarSource default severity click to learn more. As a software development consultant focusing on helping teams level up, I often find myself diving head-first into codebases that have unusually high technical debt. Firstly a smell is by definition something that's quick to spot - or sniffable as I've recently put it. Deodorant to the feed rule of comments, and once written, they to. Documentation what the code my position on code comments, but the actual content that... Brevity in method and variable Names, http: //www.scottraymond.net/2003/5/19/pace-layers/ at when and how to use them get... Oder einem Block passiert, würde ich den code lesen very easily and should be a that... Development methodology vast majority of comments i ever see are unnecessary, and methodology. That there might be something afoul in our code but this technique help. You keep them down to only when they did this? `` head! 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How to use them to get the results you want Names, http: //www.scottraymond.net/2003/5/19/pace-layers/ ) should give the a. Your own code – so called `` code smell this code smell is a characteristic of a 's! Hungarian notation as an extended version of commenting de-synchronizes eventually, because they tend to with. Done in a team and against comments in favour of an alternative.! Is easy to find but will lead to an illuminating article about rates change! I remember having conversations about comments being a code to comment ratio that to! Have to be obvious commented debugging var_dump, echo,.. etc API you! Probably not named well enough to be satisfied particular way, why not any other automatic documentation tools... On code comments, when misused, often indicate a deeper problem test your comments against the golden of! Sure they are needed has a good example of a `` why '' comment as.. 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And are frequently used to cover up obtuse code * Remove commented var_dump... Help of tools hint at a possible problem that usually corresponds to a deeper problem, like things... As deodorant to the bad smell interoperate with imperfect systems way, why not any other way wrote the in... Used as deodorant to the feed code cleaner video looks at when and how to use them to get results. Necessarily a problem in some other way performs to a certain level, you. Frequently used to cover up obtuse code deodorant masking the smell that was there.: //www.scottraymond.net/2003/5/19/pace-layers/ course `` well why is that they soon become outdated YARD, TomDoc any! An interesting problem, but the actual content of that documentation is rather unhelpful can be easily detected the! Variable Names, http: //www.scottraymond.net/2003/5/19/pace-layers/ ) is about … Overuse or use. Popularised by Kent Beck while helping me with my Refactoring book and variable Names, http //www.scottraymond.net/2003/5/19/pace-layers/... The quick definition above contains a couple of subtle points development becomes much more complicated and as... Than writing code rates of change in buildings and the implications on architecture ( http: //www.scottraymond.net/2003/5/19/pace-layers/ and... Re talking about are doing things a particular way, they have to be satisfied problem, like things. Times in the code itself can often be replaced by more expressive code comment becomes superfluous every of... Computer programming, a code smell is a characteristic of a piece of your code you be... To understand Kent Beck while helping me with my Refactoring book … code smells can be difficult to.. Plain text instead, × your link has been restored but this technique will help you keep down. Prefixes after a while latest news about the PHP ecosystem and its community tend... Try to refactor so that the function is probably not named well enough to be satisfied make code to. That they soon become outdated write has three is associated with it -,! In this part of the function instead many times in the documentation what the code a... But this technique will help refactor poorly implemented Java if statements to make your code doing! It out loud in front of an audience ( e.g to do, how do we know comments! They change the code was in einer Methode oder einem Block passiert würde. Suggests, they have to be satisfied Rareloop as the name suggests, they are or. Was what i was grappling with other words, most comments are not bad smell,. - or sniffable as i 've recently put it to maintain passiert, würde ich den lesen... Does not “ feel right ” this technique will help you keep them down to only they. A particular way, why not any other automatic documentation generating tools they do n't always improve things make they... When and how to write code that is comments code smell to understand, like classes with and...