How to Find the Stinky Parts of Your Code [Part XXXIV]

It smells because there are likely many instances where it could be edited or improved. Most of these smells are just hints of something that might be wrong. Therefore, they are not required to be fixed per se… (You should look into it, though.) Previous Code Smells You can find all the previous code smells (Part i - XXXIII) . here Let's continue... Code Smell 166 - Low-Level Errors on User Interface Fatal error: Uncaught Error: Class 'logs_queries_web' not found in /var/www/html/query-line.php:78 Stack trace: #0 {main} thrown in /var/www/html/query-line.php on line 718 TL;DR: Catch your errors. Even the ones you don't expect. Problems Security Error Handling Error Logging Bad UX Experience Solutions Use a top-level handler. Avoid languages favoring . return codes Expect database and low-level errors. Context Even in 2022, we can see "serious" websites showing casual users a stack or debugging message. Sample Code Wrong description()) // We don't show Exception to final users } // Set user-defined exception handler function set_exception_handler("myException"); Detection Automatic [x] We can use mutation testing to simulate problems and see if they are handled correctly. Tags Security Conclusion We need to keep maturing. Our solutions shouldn't be sloppy. We need to improve our reputation as serious software engineers. Relations Code Smell 72 - Return Codes More Info Fail Fast Disclaimer Code Smells are just my . opinion Credits Photo by on jesse orrico Unsplash 80 percent of my problems are simple logic errors. 80 percent of the remaining problems are pointer errors. The remaining problems are hard. Mark Donner Software Engineering Great Quotes Code Smell 167 - Hashing Comparison Hashing guarantees two objects are different. Not that they are the same. TL;DR: If you check for the hash, you should also check for equality Problems Bijection fault Solutions Check for hash (fast), and then check for Equality (slow) Context On Oct 7th, 2022, one of the larger blockchains had to be halted. was shocking since most blockchains are decentralized by definition. This news You can read a full article here: How a Hacker Stole $566M USD Exploiting a Code Smell Sample Code Wrong public class Person { public String name; // Public attributes are another smell @Override public boolean equals(Person anotherPerson) { return name.equals(anotherPerson.name); } @Override public int hashCode() { return (int)(Math.random()*256); } // This is just an example of non-correlation // When using HashMaps we can make a mistake // and guess the object is not present in the collection } Right public class Person { public String name; // Public attributes are another smell @Override public boolean equals(Person anotherPerson) { return name.equals(anotherPerson.name); } @Override public int hashCode() { return name.hashCode(); } // This is just an example of non-correlation } Detection Semi-Automatic [x] Many linters have rules for hash and equality redefinition. With mutation testing, we can seed different objects with the same hash and check our tests. Identity Security Conclusion Every performance improvement has its drawbacks. Caches and replications are notable examples. We can (must) use them carefully. Relations Code Smell 49 - Caches Code Smell 150 - Equal Comparison More Info Equality and Hash Hashcode in Java Hashcode vs Equal Disclaimer Code Smells are just my . opinion This will surprise some of your readers, but my primary interest is not with computer security. I am primarily interested in writing software that works as intended. Wietse Venema Software Engineering Great Quotes Code Smell 168 - Undocumented Decisions We need to make some changes. We need to be clear on why TL;DR: Be declarative on your design or implementation decisions. Problems Code Comments Lack of testability Solutions Be Explicit about the reasons. Convert the comment to a method. Context Sometimes we find arbitrary rules not so easily testable. If we cannot write a failing test, we need to have a function with an excellent and declarative name instead of a comment. Sample Code Wrong // We need to run this process with more memory set_memory("512k) run_process(); Right increase_memory_to_avoid_false_positives(); run_process(); Detection Semi-Automatic [x] This is a semantic smell. We can detect comments and warn us. Tags Comments Conclusion Code is prose. And design decisions should be narrative. Relations Code Smell 05 - Comment Abusers Code Smell 75 - Comments Inside a Method Disclaimer Code Smells are just my . opinion Credits Photo by on Goh Rhy Yan Unsplash Programs, like people, get old. We can’t prevent aging, but we can understand its causes, limit its effects and reverse some of the damage. Mario Fusco Software Engineering Great Quotes Code Smell 169 - Glued Methods Don't make two or more things at once. TL;DR: Try to be as atomic as possible in your methods Problems Coupled Code Harder to test Harder to read Solutions Break the method Refactorings https://maximilianocontieri.com/refactoring-002-extract-method Context If you name a method with 'And', you are probably missing an extract-and-break method opportunity. Sample Code Wrong calculatePrimeFactorsRemoveDuplicatesAndPrintThem() // Three responsibilities Right calculatePrimeFactors(); removeDuplicates(); printNumbers(); // Three different methods // We can test them and reuse them Detection Semi-Automatic [x] Some linters can warn us about methods including the term 'and'. Tags Coupling Conclusion When making methods, it is very important to play some rubber duck story and tell ourselves if we are making things right. Relations %[ ] https://maximilianocontieri.com/code-smell-85-and-functions Disclaimer Code Smells are just my . opinion Credits Photo by on Scott Sanker Unsplash Learning the art of programming, like most other disciplines, consists of first learning the rules and then learning when to break them. Joshua Bloch Code Smell 170 - Refactor With Functional Changes Developing is great. refactoring is amazing. Don't make it at the same time TL;DR: Don't change functionally and refactor at the same time. Problems Hard to review solutions Merge Conflicts Solutions Never change functionality while refactoring Context Sometimes we detect a refactoring is needed for further development. We are experts at learning. We should put our solution on hold. Work on the refactoring, and continue with our solution. Sample Code Wrong getFactorial(n) { return n * getFactorial(n); } // Rename and Change factorial(n) { return n * factorial(n-1); } // This is a very small example // Things go works while dealing with huge code Right getFactorial(n) { return n * getFactorial(n); } // Change getFactorial(n) { return n * getFactorial(n-1); } // Run the tests factorial(n) { return n * factorial(n-1); } // Rename Detection This is a refactoring smell. Manual [x] Tags Refactoring Conclusion We should use a physical token. Either we are in the refactoring stage or the developing stage. Disclaimer Code Smells are just my . opinion Credits Photo by on Dannie Jing Unsplash When I’m studying code, refactoring leads me to higher levels of understanding that I would otherwise miss. Those who dismiss comprehension refactoring as useless fiddling with the code don’t realize they never see the opportunities hidden behind the confusion. Martin Fowler 5 more code smells are coming soon…