280 reads

How to Find The Stinky Parts of Your Code [Part XV]

by Maximiliano ContieriMarch 23rd, 2022

Too Long; Didn't Read

We look at some possible solutions to various code smells. We also look at a possible solution to the problems: "Decimals" and "Accidental Complexity"

People Mentioned

Coin Mentioned

featured image - How to Find The Stinky Parts of Your Code [Part XV]

Infinite code smells!

We see several symptoms and situations that make us doubt the quality of our development.

Let's look at some possible solutions.

Most of these smells are just hints of something that might be wrong. They are not rigid rules.

Previous Code Smells

Let's continue...

Code Smell 71 - Magic Floats Disguised as Decimals

TL;DR Don't trust numbers on immature languages like JavaScript.

Problems

Principle of Least Surprise Violation
Accidental Complexity
Wrong decimal representations.

Solutions

Choose Mature Languages.
Represent Decimals with Decimals.

Sample Code

Wrong

console.log(0.2 + 0.1) 
// 0.30000000000000004

//We are adding two decimal numbers
// 2/10  +  1/10 
// Result should be 3/10 as we learnt at school

Right

class Decimal {
  constructor(numerator) {
    this.numerator = numerator;    
  }
   plus(anotherDecimal) {
      return new Decimal(this.numerator + anotherDecimal.numerator);
  }
   toString() {
      return "0." + this.numerator;
   }}     
  
console.log((new Decimal(2).plus(new Decimal(1))).toString());
// 0.3

//We can represent the numbers with a Decimal class (storing only the numerator)
//or with a generic Fraction class (storing both the numerator and denominator)

Detection

Since this is a language feature, it is difficult to detect. We can ask our linters to prevent us from manipulating numbers this way.

Conclusion

My first programming language was Commodore 64's basic back in 1985.

I was very surprised to discover that 1+1+1 was not always 3. Then they introduced integer types.

JavaScript is 30 years younger, and it has the same immaturity problems.

More info

Here is the technical (and accidental) explanation:

https://blog.pankajtanwar.in/do-you-know-01-02-03-in-javascript-here-is-why

Please, don't argue telling this is fine and expected since this is the binary representation.

These numbers are decimals, we should represent them as decimals. If you think representing them as floats is a great performance improvement, you are wrong. Premature optimization is the root of all evil.

Floating Point Standard - 83 pages

The purpose of computing is insight, not numbers -Richard Hamming

Code Smell 72 - Return Codes

APIs, Return codes, C Programming Language, We've all been there.

TL;DR: Don't return codes to yourself. Raise Exceptions.

Problems

IFs
Code Polluting
Outdated documentation
Coupling to accidental codes.
Functional logic polluted.

Solutions

Change Ids and return Generic Exceptions.
Distinguish Happy Path from Exception Path.

Sample Code

Wrong

function createSomething(arguments) {
    //Magic Creation
    success = false; //we failed

    //We failed to create
    if (!success) {
        return {
            object: null,
            errorCode: 403,
            errorDescription: 'We didnt have permddtttttttttission to create...'
        };
    }

    return {
        object: createdObject,
        errorCode: 400,
        errorDescription: ''
    };
}

var myObject = createSomething('argument');
if (myObject.errorCode != 400) {
    console.log(myObject.errorCode + ' ' + myObject.errorDescription)
}
//but myObject does not hold My Object but an implementative
//and accidental array 
//from now on me need to remember this

Right

function createSomething(arguments) {
    //Magic Creation
    success = false; //we failed

    //We failed to create
    if (!success) {
        throw new Error('We didnt have permission to create...');
    }

    return createdObject;
}

try {
    var myObject = createSomething('argument');
    //no IFS, just happy path
} catch (exception) {
    //deal with it!
    console.log(exception.message);
}
// myObject holds my expected object

Detection

We can teach our linters to find patterns of integer and strings returns coupled with ifs and return checking.

Conclusion

Ids and codes are external identifiers.
They are useful when you need to interact with an external system (for example an API Rest).
We should not use them on our own systems and our own internal APIs.
Create and raise generic exceptions.
Only create specific exceptions if you are ready to handle them, and they have specialized behavior.
Don't create anemic Exceptions.
Avoid immature and premature optimized languages favoring return codes.

More info

https://hackernoon.com/how-to-get-rid-of-annoying-ifs-forever-zuh3zlo

http://nicolecarpenter.github.io/2016/03/15/clean-code-chapter-7-error-handling.html

Error handling is important, but if it obscures logic, it’s wrong - Robert Martin

Code Smell 73 - Exceptions for Expected Cases

Exceptions are handy Gotos and flags. Let's abuse them.

TL;DR: Do not use exceptions for flow control.

Problems

Readability
Principle of least astonishment Violation.

Solutions

Use Exceptions just for unexpected situations.
Exceptions handle contract violations. Read the contract.

Sample Code

Wrong

try {
	for (int i = 0;; i++)
		array[i]++;
	} catch (ArrayIndexOutOfBoundsException e) {}

//Endless loop without end condition

Right

for (int index = 0; index < array.length; index++)
		array[index]++;

//index < array.length breaks execution

Detection

This is a semantic smell. Unless we use machine learning linters it will be very difficult to find the mistakes.

Conclusion

Exceptions are handy, and we should definitively use them instead of returning codes.

The boundary between correct usage and wrong usage is blur like so many design principles.

Relations

Code Smell 72 - Return Codes

More info

When debugging, novices insert corrective code; experts remove defective code - Richard Pattis

Code Smell 74 - Empty Lines

Breaking the code to favor readability asks for refactor.

TL;DR Don't add empty lines to your methods. Extract them!

Problems

Readability
Kiss
Low Reuse

Solutions

Extract Method
Refactor
Remove unneeded lines.

Sample Code

Wrong

<?

function translateFile() {
    $this->buildFilename();
    $this->readFile();
    $this->assertFileContentsAreOk();
    //A lot of lines more
    
    //Empty space to pause definition    
    $this->translateHiperLinks();
    $this->translateMetadata();
    $this->translatePlainText();
    
    //Yet Another empty space
    $this->generateStats();
    $this->saveFileContents();
    //A lot of more lines
}

Right

<?

function translateFile() {
    $this->readFileToMemoy();
    $this->translateContents();
    $this->saveFileContents();  
}

Detection

This is a policy smell. Every linter can detect blank lines and warn us.

Conclusion

Empty lines are harmless, but show us an opportunity to break the code into small steps.

If you break your code with comments, it is also a code smell asking for a refactor.

It’s OK to figure out murder mysteries, but you shouldn’t need to figure out code. You should be able to read it - Steve McConnell

Code Smell 75 - Comments Inside a Method

Comments are often a code smell. Inserting them inside a method calls for an urgent refactor.

TL;DR Don't add comments inside your methods. Extract them and leave declarative comments just for not obvious design decisions.

Problems

Readability
Kiss
Low Reuse
Bad Documentation

Solutions

Extract Method
Refactor
Remove not declarative comments.

Sample Code

Wrong

function recoverFromGrief() {
    // Denial stage
    absorbTheBadNews();
    setNumbAsProtectiveState();
    startToRiseEmotions();
    feelSorrow();

    // Anger stage
    maskRealEffects();
    directAngerToOtherPeople();
    blameOthers();
    getIrrational();

    // bargaining stage
    feelVulnerable();
    regret();
    askWhyToMyself();
    dreamOfAlternativeWhatIfScenarios();
    postoponeSadness();

    // depression stage
    stayQuiet();
    getOverwhelmed();
    beConfused();

    // acceptance stage
    acceptWhatHappened();
    lookToTheFuture();
    reconstructAndWalktrough();
}

Right

function recoverFromGrief() {
    denialStage();
    angerStage();
    bargainingStage();
    depressionStage();
    acceptanceStage();
}

function denialStage() {
    absorbTheBadNews();
    setNumbAsProtectiveState();
    startToRiseEmotions();
    feelSorrow();
}

function angerStage() {
    maskRealEffects();
    directAngerToOtherPeople();
    blameOthers();
    getIrrational();
}

function bargainingStage() {
    feelVulnerable();
    regret();
    askWhyToMyself();
    dreamOfAlternativeWhatIfScenarios();
    postoponeSadness();
}

function depressionStage() {
    stayQuiet();
    getOverwhelmed();
    beConfused();
}

function acceptanceStage() {
    acceptWhatHappened();
    lookToTheFuture();
    reconstructAndWalktrough();
}