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 - XXXI) . here Let's continue... Code Smell 156 - Implicit Else We learn if/else on our first programming day. Then we forget the else. TL;DR: Be explicit. Even with Else. Problems Readability Cognitive Load Unforeseen conditions Fail Fast Principle violation Solutions Write the explicit else Context If we early return on an IF sentence, we can omit the else part. Afterward, we and use polymorphism. Remove the IF That is when we miss the real cases. Sample Code Wrong function carBrandImplicit(model) {
  if (model === 'A4') {
    return 'audi';
  }
  return 'Mercedes-Benz';
} Right function carBrandExplicit(model) {
  if (model === 'A4') {
    return 'audi';
  }
  if (model === 'AMG') {
    return 'Mercedes-Benz';
  }
  
  // Fail Fast
  throw new Exception('Model not found);
} Detection Automatic [x] We can check syntax trees and parse them and warn for missing else. We can also rewrite them and perform mutation testing. Tags Conditionals Conclusion This kind of smell brings a lot of public debate . and hate We must exchange opinions and value each pro and cons. Relations Code Smell 102 - Arrow Code Code Smell 36 - Switch/case/else if/else/if statements More Info Stop Using Implicit Else When To Use Implicit Else Fail Fast How to Get Rid of Annoying IFs Forever Credits Photo by on Elena Mozhvilo Unsplash The biggest issue on software teams is making sure everyone understands what everyone else is doing. Martin Fowler Code Smell 157 - Balance at 0 Today, I expected a payment in my wallet. The balance was 0. I panicked. TL;DR: Null is not 0. Error is not 0. just 0 is 0. Problems Nulls UX Usability Solutions Make a clear distinction between a Zero and an error. Context I read a lot about security issues. Especially on crypto. Last week, I read about a . crypto hack thread When my wallet showed me 0 as a balance, I panicked. It was just a UX smell. The blockchain was unreachable 💩 Sample Code Wrong """
Below code is automatically generated by code-davinci-002 on GTP3 Codex

1. check balance with blockchain
2. If blockchain is unreachable show 0 as the balance
"""

import requests
import json

def get_balance(address):
    url = "https://blockchain.info/q/addressbalance/" + address
    response = requests.get(url)
    if response.status_code == 200:
        return response.text
    else:
        return 0 Right """
Below code is automatically generated by code-davinci-002 on GTP3 Codex

1. check balance with blockchain
2. If blockchain is unreachable throw an error
"""

import requests
import json

def get_balance(address):
    url = "https://blockchain.info/q/addressbalance/" + address
    response = requests.get(url)
    if response.status_code == 200:
        return response.text
    else:
        raise BlockchainNotReachableError("Error reaching blockchain") Detection Manual [x] This is a design smell. We can find patterns when an or is thrown and masked with a 0. exception return code Tags UX Conclusion Always follow The as a guide. Least Astonishment principle Relations Code Smell 12 - Null Code Smell 139 - Business Code in the User Interface Code Smell 73 - Exceptions for Expected Cases Code Smell 72 - Return Codes More Info Null: The Billion Dollar Mistake Credit Photo by on Jasmin Sessler Unsplash Disclaimer Code Smells are just my . opinion My real criticism with Null is that it brings back again unnecessarily all the agony of having to choose whether to run your program fast without checking or run it slow with checking. (Null Inventor) Tony Hoare Software Engineering Great Quotes Code Smell 158 - Variables Not Variable You assign a value to a variable and use it but never change it. TL;DR: Be declarative on mutability. Problems Readability Honor the mutability. Bijection Potential performance and memory issues. Solutions Change and be clear on its scope. the variable to a constant Refactorings Refactoring 003 - Extract Constant Refactoring 008 - Convert Variables to Constant Context We are always learning from the domain. Sometimes we guess that a value can change with the . MAPPER Later on, we learn it won't change. Therefore, we need to promote it to a constant. This will also avoid . Magic Constants Sample Code Wrong <?php

function configureUser() {
  $password = '123456';
  // Setting a password on a variable is another vulnerability
  // And Code Smell
  $user = new User($password);
  // Notice Variable doesn't change
} Right <?php

define("USER_PASSWORD", '123456')

function configureUser() {  
  $user = new User(USER_PASSWORD);
}

// or 

function configureUser() {  
  $user = new User(userPassword());
}

function userPassword() : string {
  return '123456';
}

// Case is an oversimplification as usual Detection Automatic [x] Many linters check if the variable has just one assignment. We can also perform mutation testing, and try to modify the variable to see if the tests break. Tags Mutability Conclusion We must challenge ourselves and refactor when the variable scope is clear, and we learn more about its properties and . mutability Relations Code Smell 116 - Variables Declared With 'var' Code Smell 127 - Mutable Constants Code Smell 107 - Variables Reuse Code Smell 02 - Constants and Magic Numbers More Info The Evil Power of Mutants Disclaimer Code Smells are just my . opinion Credits Photo by on Noah Buscher Unsplash A complex system that works is invariably found to have evolved from a simple system that worked. John Gall CoDe SmElL 159 - mIxEd_cASeI Serious development is done by many different people. We have to start agreeing. TL;DR: Don't mix different case conversions Problems Readability Maintainability Solutions Choose a case standard Hold on to it Context When different people make software together, they might have personal or cultural differences. Some prefer 🐫, others 🐍, MACRO_CASE🗣️, and . camelCase snake_case many others The code should be straightforward and readable. Sample Code Wrong {
    "id": 2,
    "userId": 666, 
    "accountNumber": "12345-12345-12345",
    "UPDATED_AT": "2022-01-07T02:23:41.305Z",
    "created_at": "2019-01-07T02:23:41.305Z",
    "deleted at": "2022-01-07T02:23:41.305Z"
} Right {
    "id": 2,
    "userId": 666, 
    "accountNumber": "12345-12345-12345",
    "updatedAt": "2022-01-07T02:23:41.305Z",
    "createdAt": "2019-01-07T02:23:41.305Z",
    "deletedAt": "2022-01-07T02:23:41.305Z"
  // This doesn't mean THIS standard is the right one
} Detection Automatic [x] We can tell our linters about our company's broad and enforce them. naming standards Whenever new people arrive at the organization, an automated test should politely ask him/her/.. to change the code. Exceptions Whenever we need to interact with out-of-our-scope code, we should use the client's standards, not ours. Tags Naming Conclusion Dealing with standards is easy. We need to enforce them. Relations Code Smell 48 - Code Without Standards More Info What exactly is a name - Part I The Quest All naming conventions Disclaimer Code Smells are just my . opinion Credits Photo by on Wolfgang Hasselmann Unsplash If you have too many special cases, you are doing it wrong. Craig Zerouni Code Smell 160 - Invalid Id = 9999 Maxint is a very good number for an invalid ID. We will never reach it. TL;DR: Don't couple real IDs with invalid ones. In fact: Avoid IDs. Problems violation. Bijection You might reach the invalid ID sooner than your think. Don't use for invalid IDs either. nulls Coupling flags from caller to functions. Solutions Model special cases with special objects. Avoid 9999, -1, and 0 since they are valid domain objects and implementation coupling. Introduce Null Object Context In the early days of computing, data types were strict. Then we invented . The billion-dollar mistake Then we grew up and modeled special scenarios with polymorphic special values. Sample Code Wrong #include "stdio.h"
#include "stdlib.h"
#include "stdbool.h"
#define INVALID_VALUE 999

int main(void)
{    
    int id = get_value();
    if (id==INVALID_VALUE)
    { 
        return EXIT_FAILURE;  
        // id is a flag and also a valid domain value        
    }
    return id;
}

int get_value() 
{
  // something bad happened
  return INVALID_VALUE;
}

// returns EXIT_FAILURE (1) Right #include "stdio.h"
#include "stdlib.h"
#include "stdbool.h"
// No INVALID_VALUE defined

int main(void)
{    
    int id;
    id = get_value();
    if (!id) 
    { 
        return EXIT_FAILURE;
        // Sadly, C Programming Language has no exceptions
    }  
    return id;
}  

get_value() 
{
  // something bad happened
  return false;
}

// returns EXIT_FAILURE (1) Detection Semi-Automatic [x] We can check for special constants and special values in the code. Tags Null Conclusion We should use numbers to relate to the external identifiers. If no external identifier exists, then it is not a number. Relations Code Smell 120 - Sequential IDs Code Smell 12 - Null More Info Null: The Billion Dollar Mistake Y2K22 - The Mistake That Embarrasses Us Disclaimer Code Smells are just my . opinion Credits Photo by on Markus Spiske Unsplash Bugs lurk in corners and congregate at boundaries. Boris Beizer 5 more code smells are coming soon…

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