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Cover image for Code Smell 224 - Deodorant Comments
Maxi Contieri
Maxi Contieri

Posted on • Originally published at

Code Smell 224 - Deodorant Comments

You use nice words to excuse bad code

TL;DR: Don't excuse bad code. Write a clean one!


  • Readability


  1. Rewrite the code and delete the comment


The term comes from Martin Fowler's book "Refactoring: Improving the Design of Existing Code"

Sample Code


# This is a function that adds two numbers
def s(a, b):
    # Now you are going to add a and b
    res = a + b
    # And return the result
    return res

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def sum(adder, anotherAdder):

    return adder + anotherAdder
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If you ask ChatGPT to improve this version it will actually worsen it:

def calculate_sum(number1, number2):
    # Calculate the sum of two numbers
    result = number1 + number2
    return result

# In this improved version:
# The function name calculate_sum is more descriptive than sum, 
# making it clear that this function calculates the sum of two numbers.
# (Wrong) it is more imperative and mistakes the 'what' with the 'how'
# The parameter names number1 and number2 are more meaningful 
# than adder and anotherAdder, helping to indicate the purpose of each parameter.
# (wrong) They indicate type instead of role
# The comment # Calculate the sum of two numbers provides a clear 
# and concise explanation of what the function does, 
# making it easier for someone reading the code to understand its purpose.    
# (wrong) in fact, it is an example of deodorant and useless comment
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[X] Semi-Automatic

Most comments are code smells.

You can remove deodorant comments and improve the code.


  • Comments should only be used to describe important design decisions.


  • Comments


Remove any meaningless comment you find in your code.


More Info

Clean Code In C#


Code Smells are my opinion.


Photo by Ana Essentiels on Unsplash

The reason we mention comments here is that comments often are used as a deodorant. It's surprising how often you look at thickly commented code and notice that the comments are there because the code is bad.

Martin Fowler

This article is part of the CodeSmell Series.

Top comments (2)

cicirello profile image
Vincent A. Cicirello

I like your example of how ChatGPT takes the smell-free version and introduces at least 3 smells into a simple function.

mcsee profile image
Maxi Contieri

Thank you.
We need to be in control and don't trust them blindly