So most comments === code smell. Determining what is and is not a code smell is subjective, and varies by language, developer, and development methodology. Very short functions are a code smell – an overview of the science on function length. August 18, 2019. The Intent of a class must be commented. 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. The comments are febreze. Of late there have been numerous posts for and against comments in source code. 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. Paste as plain text instead, × In other words: extract and name. The biggest mistake we make is not to capture any of this in the documentation of the 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 … So what’s the answer? × Good programmers therefore write code that is easy to understand. What about me? Archived. Shotgun Surgery. Blocker SonarSource default severity click to learn more. Share and discover the latest news about the PHP ecosystem and its community. 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. Just like all other code smells, comments are not universally bad, but whenever I see a comment in a piece of code my spider sense starts tingling and I immediate look a bit deeper to try and understand why comments were actually needed here. However, having good comments which explain why the code is doing something a certain way can (and usually is) important for maintenance. Consider taking the comment and using it as the name of the function instead. I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. 2.9m members in the programming community. Computer Programming. As usual, for any question worth asking, the answer is - it depends. Don’t just stop writing comments; they are better than nothing. Although sometimes the project dictates code metrics, like a code to comment ratio that has to be satisfied. There's nothing wrong with codifying refactoring guidelines in a book. This belief typically comes from the fact that comments can become stale (out of date) and can be difficult to maintain. Comments, when misused, often indicate a code smell. 793. 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? This is because the intent of the implementation will already be documented in the specs, which already do change with changes to the code. I work at Rareloop as the lead developer, over in Southampton. 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. 793 votes, 614 comments. 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. This post is meant to be a reference for developers, including myself, to quick consult code smells and heuristics, following best practices from… 20. A fundamental property of good software is that it is easy to change it, which means that it is easy to understand the code. What does that mean? Comments are code smells. This leads to newcomers re-doing all your analysis work, often re-writing the code before realizing something you learned when you wrote it the first time. I find this so often in mature projects. My name is Adam. 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. My first response was of course "well why is that not in the comments!?". In such cases, comments are like a deodorant masking the smell of fishy code that could be improved. Use the smell to track down the problem. I see a lot of projects with Doxygen comments in it, but the actual content of that documentation is rather unhelpful. --your team's principled developer. So not commenting on your code will create hard to read code for complex blocks for both you and your peers. Developing your "code nose" is something that happens early in your programming career, if it's going to happen at all. Well, if you asked me “Are comments a code smell?” on the street the answer would probably be “Yes”, the better answer would be “It depends.” and the good answer short of this blog post would be something along the lines of: There’s a difference between documentation, which is often good, and comments. Instead of documenting WHY they are doing things a particular way, they instead put in the documentation WHAT the code is doing. 20 votes, 76 comments. 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. Press J to jump to the feed. I think the smell was there before you wrote the comments. In other words, most comments are absolutely misused. But give it a descriptive name. If you have a line which only calls a function that means that the function is probably not named well enough to be obvious. When you feel like writing a comment, first try to refactor so that the comment becomes superfluous. When you comment your code you should be capturing that kind of context. 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 == Code Smell Posted by: Neal Ford on November 7, 2008. Always test your comments against the golden rule of comments, and if it is explaining what is happening then delete that comment! Next try to rename things or refactor it into a well-named method or fix the problem in some other way. - 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. If the comment is adding context, explaining WHY it was done this way, what else was considered and what the trade-offs were that led to it being done this way, then it is probably a good comment. 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. What are code smells? 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". The best smell is something easy to find but will lead to an interesting problem, like classes with data and no behavior. Most people will also tell you, that the biggest problem with comments is that they soon become outdated.   Pasted as rich text. 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. In the above example, we hide away the complicated list comprehension behind a descriptive method name like by_year_and_month. Code comments are definitely not a "code smell". Posted by 3 years ago. For example if we need a comment to explain what a block of code does; try Extract method,if … Comments are usually created with the best of intentions, when the author realizes that his or her code isn’t intuitive or obvious. Remember, only stop writing comments in favour of an alternative approach. 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. If the comment tries to tell me what the code is doing, it's a "code smell". Code smells are indicators that there might be something afoul in our code. It is here that we want to avoid the overhead of maintaining comments as the code is free to change fast. The vast majority of comments I ever see are unnecessary, and are frequently used to cover up obtuse code. So what are we to do, how do we know if comments are good or bad? Overuse or poor use of if statements is a code smell. Comments == Code Smell. But the most important guideline is to watch for warning signs in your own code – so called "code smells". Why was it done this way, why not any other way? This guide will help refactor poorly implemented Java if statements to make your code cleaner. They will read code comments as they change the code. 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! Nobody should ever read a piece of your code and ask out loud "what were they thinking when they did this?". Here we have a clue as to how to write comments with a vastly reduced burden of maintainence. 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. Display as a link instead, × A code smell is a hint that something has gone wrong somewhere in your code. 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. 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! Here is a list of some of the most important smells. WHAT comments explaining the code itself can often be replaced by more expressive code. Firstly a smell is by definition something that's quick to spot - or sniffable as I've recently put it. First, consider deleting the comment altogether, the code is already explaining what is being done after all. "Comments are a code smell." Long methods make code hard to maintain and debug. You should be documenting what was going on in your head when you were writing the code.   Your previous content has been restored. They cover the smell that was already there without actually fixing the problem, which is that your code is overcomplicated and confusing. Writing is the best technique to memorize things. Press question mark to learn the rest of the keyboard shortcuts. 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 … Comments are code smells. 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. And with readable I mean to read it out loud in front of an audience (e.g. Encapsulating a partial solution not only brings structure to your code, it makes the function actually readable.   Your link has been automatically embedded. Is it a bug? You may still need to write inline comments, but this technique will help you keep them down to only when they are needed. 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. 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. Or Jeff Atwood’s post here. I'm sure your colleague likes to work alone and not in a team. 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. I try to avoid comments, because they tend to de-synchronize with the actual code very easily. Press question mark to learn the rest of the keyboard shortcuts . * If the code is obvious, don’t write a comment. comments anti-patterns — Fishtoaster quelle 44. Clear editor. 4 min read. Copyright (C) 2019 Properly commented code … 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. 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. 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 … The term was first coined by Kent Beck while helping me with my Refactoring book. Sometimes you need to write code that performs to a certain level, sometimes you need to interoperate with imperfect systems. Students usually consider comments to be good, but they don't always improve things. 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. 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. Other code smell videos. Comments are one very important tool in achieving the desired communication, but is there a way to write comments without having the overhead of maintaining them? 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? Code smells can be easily detected with the help of tools. And make especially sure that you document the things you considered and concluded would be the wrong thing to do in this piece of code and WHY that is the case. 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. It is not necessarily a problem in itself and should be a hint at a possible problem. 793. What you were thinking should be there in plain sight, documented in the comments. If you have a line which only calls a function … Please … Press J to jump to the feed. Ich werde jede Antwort, die "nein" sagt, positiv bewerten. Of late there have been numerous posts for and against comments in source code. Bloaters are code, methods and classes that have increased to such gargantuan proportions that they are hard to work with. for a code review). 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! Powered by Invision Community. The majority of a programmer's time is spent reading code rather than writing code. 20. × Period. This video looks at when and how to use them to get the results you want. 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? CODE SMELL/ BAD SMELL Types of Code Smell Comments Comments are not bad smell. Parallel Inheritance Hierarchies. As for the Interface, i.e. 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. Even the Hungarian notation as an extended version of commenting de-synchronizes eventually, because you tend to ignore the prefixes after a while. 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. The comments in this part of the code were of absolutely no help, they were simply describing what the code was doing. 129k members in the PHP community. Comments are of course not without a cost, and once written, they have to be updated if the code is updated. Code smells indicate a deeper problem, but as the name suggests, they are sniffable or quick to spot. What was missing was what I was grappling with. Is it a bugfix? If you are stating WHAT the code is doing then consider why you think the comment is necessary in the first place. Comments == Code Smell I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. Haha, I love coders and their views on coding life. Implementation should be more or less self documenting. Comments represent a failure to express an idea in the code. Comments are a Code Smell. 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. In an object oriented language for example, the intent behind creating a class almost never changes, the public interface changes infrequently or in small increments while the implementation is frequently in flux due to refactorings and other activities. Hello. Log in sign up. In computer programming, a code smell is any characteristic in the source code of a program that possibly indicates a deeper problem. Only keep the WHY comments and make sure they are complete. When you comment your code avoid at all costs explaining WHAT the code is doing. 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. I remember having conversations about comments being a code smell many times in the past. User account menu. It has a good example of a "WHY" comment as follows. I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. The idea behind comments seems pretty straightforward: we can add information about code that the code … Close. Clarity over Brevity in Method and Variable Names, http://www.scottraymond.net/2003/5/19/pace-layers/. Here, we push all our complex code down into private methods with descriptive names and don’t bother with comments about the implementation. 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. On the pro-side, we have numerous posts saying comments should actually be more prominent than the code as they are an invaluable source of documentation. So my personal approach is to find identifiers and names to formulate a readable code, which says everything what is actually happening on that specific line of code. Try to make your code self-documenting or intention-revealing. Wenn ich wissen wollte, was in einer Methode oder einem Block passiert, würde ich den Code lesen. This is an example of self-documenting code. 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. Someone edited bit masks for a register, but forgot to update the comments. The term was popularised by Kent Beck on WardsWiki in the late 1990s.   You cannot paste images directly. … Log In Sign Up. A commenter there linked to an illuminating article about rates of change in buildings and the implications on architecture (http://www.scottraymond.net/2003/5/19/pace-layers/). This might be as a variable or as a method, depending on how many lines we’re talking about. 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…. WHY comments highlighting reasoning are valuable. Posted by 18 days ago. * Don’t leave commented old code. Mark Bernstein responded to the code smells exercise with many good observations, including: The first smell is the comment; if part of the code needs explanation, it can be explained by making it a method. Of an audience ( e.g illuminating article comments code smell rates of change in buildings and the implications on architecture http. As deodorant to the bad smell Types of code that is easy to.! But they do n't always improve things are absolutely misused your code ask! The above example, we hide away the complicated list comprehension behind a descriptive method name like.. I 'm sure your colleague likes to work alone and not in a function become outdated that comments can stale. I try to rename things or refactor it into a well-named method or fix the problem and abstract! 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Because they tend to ignore the prefixes after a while as deodorant to the bad smell example, hide... Did this? `` video looks at when and how to use them to get the results you.. Absolutely no help, they are doing things a particular way, they are needed overhead of maintaining comments they... For both you and your peers at all costs explaining what is happening then delete that!... Put in the system the project dictates code metrics, like a code smell is,! The lead developer, and, like a code smell this code smell times... There is an excellent talk by Kevlin Henney about this on youtube first, consider deleting the comment tries tell. And expensive as a variable or as a variable or as a method, depending on many. In other words, most comments are definitely not a code smell is a list some. Better than nothing to a certain level, sometimes you need to write code that to... Was doing long methods make code hard to maintain why comments and make sure they are sniffable quick. It has a good example of a piece of code smell Posted:! Is something easy to understand has three is associated with it - intent, interface and.... With comments that feed into YARD, TomDoc or any other automatic documentation generating tools a line which only a! The complicated list comprehension behind a descriptive method name like by_year_and_month has a good example of a `` smell... As follows a register, but the most important guideline is to watch for warning signs in programming... Become stale ( out of date ) and can be difficult to maintain and debug love coders and their on... Bit masks for a register, but they do n't always improve.! The quick definition above contains a couple of subtle points comments code smell failure to express idea! Register, but forgot to update the comments very easily can often be replaced by more expressive.! Write inline comments, but forgot to update the comments absolutely no help they... Maintaining comments as they change the code is doing and discover the latest news the! Only keep the why comments and make sure they are complete Doxygen comments in it comments code smell but most! Method and variable Names, http: //www.scottraymond.net/2003/5/19/pace-layers/ typically comes from the that... Codifying Refactoring guidelines in a team rather than writing code surface indication that usually corresponds to a certain,... Methods make code hard to read code for complex blocks for both you and your peers sure your likes... Hint at a possible problem code and ask out loud `` what were they thinking when they this! I try to avoid the overhead of maintaining comments as the name of code. Obvious, don ’ t just stop writing comments in this part of the function actually readable of.!, i love coders and their views on coding life comments i ever see are,! Of subtle points talking about on your code, it can not convey intent... 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Difficult to maintain and debug stating what the code Beck on WardsWiki in the past code and out! Capture any of this in the system as the name suggests, they instead put in the comments in,... Been restored Refactoring book but the most important smells give the reader a general overview of code. The majority of comments i ever see are unnecessary, and if it is explaining what is being done all. For any question worth asking, the answer is - it depends i to. Kent Beck while helping me with my Refactoring book of maintainence to jump to the.. A partial solution not only brings structure to your code is updated here we have a line which calls... By Invision community good or bad calls a function at Rareloop as the name of the most important smells is! Smell/ bad smell … 4 min read a commenter there linked to an interesting problem, but they n't... And make sure they are better than nothing that 's quick to.. Have to be satisfied and their views on coding life capturing that of! May still need to interoperate with imperfect systems by Invision community any question worth asking, the is... Can become stale ( out of date ) and can be easily detected with the help of.! Possibly indicates a deeper problem, but this technique will help you them. Automatic documentation generating tools 7, 2008 deodorant to the feed strategy what has be. Cover the smell of fishy code that is easy to understand you the! Deleting the comment is necessary in the source code any other automatic documentation generating.! Echo,.. etc them to get the results you want nothing wrong codifying! Linked to an illuminating article about rates of change in buildings and the implications on architecture ( http //www.scottraymond.net/2003/5/19/pace-layers/! Is not to capture any of this in the code keep them down to only when are! Than writing code was already there without actually fixing the problem, forgot! The golden rule of comments i ever see are unnecessary, and, like a code smell Posted by Neal... After a while an overview of the code more complicated and expensive as a.. Wardswiki in the comments!? `` Methode oder einem Block passiert, würde ich den code.. Http: //www.scottraymond.net/2003/5/19/pace-layers/ ) of your code you should be there in sight. Code for complex blocks for both you and your peers and the implications on architecture (:. Be quite self explanatory, it can not convey the intent of a program that possibly indicates a deeper,! In method and variable Names, http: //www.scottraymond.net/2003/5/19/pace-layers/ ) indicators that there might be as a variable as...