My name is Adam. The term was popularised by Kent Beck on WardsWiki in the late 1990s.   You cannot paste images directly. Most people will also tell you, that the biggest problem with comments is that they soon become outdated. This is because the intent of the implementation will already be documented in the specs, which already do change with changes to the code. Code smells are indicators that there might be something afoul in our code. 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. What does that mean? So to sum up, we can have comments that aren’t a code smell if we take care to comment the slow moving parts of our code such as the intent of a class and the public API. Every piece of code that you write has three Is associated with it - intent, interface and implementation. 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. You may still need to write inline comments, but this technique will help you keep them down to only when they are needed. - Speculative Generality Code Smell This code smell is about … 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. When you comment your code avoid at all costs explaining WHAT the code is doing. 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. 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. It tells you that your code is too complex. WHY comments highlighting reasoning are valuable. Clear editor. This video looks at when and how to use them to get the results you want. Here, we push all our complex code down into private methods with descriptive names and don’t bother with comments about the implementation. Firstly a smell is by definition something that's quick to spot - or sniffable as I've recently put it. There is an excellent talk by Kevlin Henney about this on youtube. 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 … If the comment tries to tell me what the code is doing, it's a "code smell". Comments == Code Smell. Sometimes you need to write code that performs to a certain level, sometimes you need to interoperate with imperfect systems. Always test your comments against the golden rule of comments, and if it is explaining what is happening then delete that comment! * Don’t leave commented old code. If you have a line which only calls a function … 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. The vast majority of comments I ever see are unnecessary, and are frequently used to cover up obtuse code. Paste as plain text instead, × * If the code is obvious, don’t write a comment. 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. 129k members in the PHP community. 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. Try to make your code self-documenting or intention-revealing. The idea behind comments seems pretty straightforward: we can add information about code that the code … I work at Rareloop as the lead developer, over in Southampton. Overuse or poor use of if statements is a code smell. All of these change at different speeds. But give it a descriptive name. 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. 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. The term was first coined by Kent Beck while helping me with my Refactoring book. Properly commented code … 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. Writing is the best technique to memorize things. WHAT comments explaining the code itself can often be replaced by more expressive code.   Pasted as rich text. Copyright (C) 2019 Comments are of course not without a cost, and once written, they have to be updated if the code is updated. This guide will help refactor poorly implemented Java if statements to make your code cleaner. Comments == Code Smell Posted by: Neal Ford on November 7, 2008. A code smell is a characteristic of a piece of code that does not “feel right”. 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. Comments are usually created with the best of intentions, when the author realizes that his or her code isn’t intuitive or obvious. I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. But the most important guideline is to watch for warning signs in your own code – so called "code smells". Press question mark to learn the rest of the keyboard shortcuts. Why was it done this way, why not any other way? Instead of documenting WHY they are doing things a particular way, they instead put in the documentation WHAT the code is doing. What you were thinking should be there in plain sight, documented in the comments. I find this so often in mature projects. Even the Hungarian notation as an extended version of commenting de-synchronizes eventually, because you tend to ignore the prefixes after a while. I remember having conversations about comments being a code smell many times in the past. User account menu. Blocker SonarSource default severity click to learn more. Hello. Only keep the WHY comments and make sure they are complete. I try to avoid comments, because they tend to de-synchronize with the actual code very easily. Is it a bugfix? Computer Programming. * Remove commented debugging var_dump, echo, ..etc. 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. Usually these smells do not crop up right away, rather they accumulate over time as the program evolves (and especially when nobody makes an effort to eradicate them). 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. A code smell is a surface indication that usually corresponds to a deeper problem in the system. Shotgun Surgery. Code smells can be easily detected with the help of tools. The comments are febreze. Students usually consider comments to be good, but they don't always improve things. 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. Comments should give the reader a general overview of the problem and an abstract strategy what has to be done in a function. Comments == Code Smell I am sometimes asked about my position on code comments, and, like most things, I have strong opinions about it. ... Nur wenn der Kommentar beschreibt, was der Code tut. 20. It is here that we want to avoid the overhead of maintaining comments as the code is free to change fast. While each individual function might be quite self explanatory, it cannot convey the intent of a class as a whole. In other words: extract and name. 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. Code comments are definitely not a "code smell". Of late there have been numerous posts for and against comments in source code. for a code review). Code smell? Implementation should be more or less self documenting. Comments are code smells. 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? 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. Share and discover the latest news about the PHP ecosystem and its community. So most comments === code smell. This post is meant to be a reference for developers, including myself, to quick consult code smells and heuristics, following best practices from… Determining what is and is not a code smell is subjective, and varies by language, developer, and development methodology. Parallel Inheritance Hierarchies. 4 min read. Very short functions are a code smell … Here we have a clue as to how to write comments with a vastly reduced burden of maintainence. Close. "Comments are a code smell." 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! 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. 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. 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. Long methods make code hard to maintain and debug. In computer programming, a code smell is any characteristic in the source code of a program that possibly indicates a deeper problem. Log In Sign Up. Good programmers therefore write code that is easy to understand. This is an example of self-documenting code. Press J to jump to the feed. Don’t just stop writing comments; they are better than nothing. The majority of a programmer's time is spent reading code rather than writing code. Very short functions are a code smell – an overview of the science on function length. 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. They cover the smell that was already there without actually fixing the problem, which is that your code is overcomplicated and confusing. 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. 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. However, having good comments which explain why the code is doing something a certain way can (and usually is) important for maintenance. User account menu. I see a lot of projects with Doxygen comments in it, but the actual content of that documentation is rather unhelpful.   Your link has been automatically embedded. Although sometimes the project dictates code metrics, like a code to comment ratio that has to be satisfied. Consider taking the comment and using it as the name of the function instead. 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". A fundamental property of good software is that it is easy to change it, which means that it is easy to understand the code. They will read code comments as they change the code. Upload or insert images from URL. What are code smells? As Henney explains English, or whatever written language for that matter, is not nearly as precise a language as the programming language used itself. First, consider deleting the comment altogether, the code is already explaining what is being done after all. --your team's principled developer. The quick definition above contains a couple of subtle points. Press question mark to learn the rest of the keyboard shortcuts . Remember, only stop writing comments in favour of an alternative approach. Clarity over Brevity in Method and Variable Names, http://www.scottraymond.net/2003/5/19/pace-layers/. Ich werde jede Antwort, die "nein" sagt, positiv bewerten. 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. You should be documenting what was going on in your head when you were writing the code. So what’s the answer? 20 votes, 76 comments. Powered by Invision Community. In other words, most comments are absolutely misused. 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. Haha, I love coders and their views on coding life. 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. Treat inline comments as code smells. 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 … I'm sure your colleague likes to work alone and not in a team. Display as a link instead, × Close. In the above example, we hide away the complicated list comprehension behind a descriptive method name like by_year_and_month. 2.9m members in the programming community. It has a good example of a "WHY" comment as follows. 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. 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? Other code smell videos. If you are stating WHAT the code is doing then consider why you think the comment is necessary in the first place. Comments, when misused, often indicate a code smell. Divergent Change. 793. Next try to rename things or refactor it into a well-named method or fix the problem in some other way. When you comment your code you should be capturing that kind of context. 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. 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 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! 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…. 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. The comments in this part of the code were of absolutely no help, they were simply describing what the code was doing. I think the smell was there before you wrote the comments. Someone edited bit masks for a register, but forgot to update the comments. Nobody should ever read a piece of your code and ask out loud "what were they thinking when they did this?". A code smell is a hint that something has gone wrong somewhere in your code. 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. 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. Posted by 18 days ago. And with readable I mean to read it out loud in front of an audience (e.g. 793 votes, 614 comments. So not commenting on your code will create hard to read code for complex blocks for both you and your peers. Of late there have been numerous posts for and against comments in source code. Encapsulating a partial solution not only brings structure to your code, it makes the function actually readable. Comments are code smells. 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. 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. 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. As usual, for any question worth asking, the answer is - it depends. … 4 min read strong opinions about it although sometimes the project dictates code metrics, like code! Are good or bad developing your `` code smell this code smell is subjective, and are frequently used cover. Students usually consider comments to be obvious ever read a piece of code that could be improved its! Instead of documenting why they are doing things a particular way, not... And varies by language, developer, and varies by language, developer, varies. Powered by Invision community and your peers missing was what i was grappling with only. 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Was what i was grappling with against comments in favour of an alternative approach represent a failure to express idea. Put it language, developer, and if it 's a `` why '' comment as.. It depends ; they are needed important smells a smell is subjective, and like... In a book version of commenting de-synchronizes eventually, because they tend to ignore the prefixes a... Is doing then consider why you think the smell that was already without... Masks for a register, but forgot to update the comments in part! Fishy code that is easy to understand your peers it, but they n't... Program development becomes much more complicated and expensive as a variable or a... Likes to work alone and not in the comments Rareloop as the code is free to fast. They will read code for complex blocks for both you and your peers you... This way, why not any other way results you want much more complicated and expensive as result. Necessary in the past make code hard to read it out loud `` what they!