image shows duplicate lines in code

What is duplicate code?

What is duplicate code?

Duplicate code as the name suggests is a repetition of a line or a block of code in the same file or sometimes in the same local environment. What people might consider as acceptable, duplicate code poses greater problems to your software than what you may have thought. Even codes that have similar functionalities are said to be duplications.

image shows duplicate lines in code

The main reason for creation for the duplicate code is Copy and Paste Programming. Developers justify this practice of plagiarism by commenting that this section of code works for the program, and to make it look original modify variables and architecture of the code. They ignore that most programs they scrounge are made for academic purposes and strictly not for commercial development. So they contain redundant data so that the program is understandable. Efficiency is the last preference in an academic environment, while it’s the first in the commercial sphere. Developers use copy-paste programming also because they don’t know about the language that much. 

The fact is, no one likes repetitions. Your teacher at UNI didn’t when you wrote redundant answers and neither so your software does when you write duplicate codes.

Here are 4 reasons why the duplicate code is harmful to your software:


Duplicate code makes your program lengthy and bulky:                 

When you write duplicate codes thinking that if code ain’t broke, there is no reason to fix it. You forget that you are just un-necessarily making your software bulky. Your argument can be a few blocks of code would just use a few milliseconds of time to run. Which we agree to but only if you mean to use your software a few times. Code written for commercial purposes or for web-applications is executed thousands and millions of times every minute. Each millisecond of delay will contribute to greater delay and greater space requirements at the user’s local machine as well as your servers. Having well-written code with least duplications will make sure that your program runs faster and occupy less space. Also, age has gone when people didn’t care to wait. Now everything needs to be fast and smooth.

Duplicate code decreases your code quality

Have duplication is fine, as long as you plan to throw your software away soon. Code quality is a necessity to make your software survive for long. Having duplicate code will make your code smelly and increases technical debt associated with it. The cost of repair of this debt is the amount of capital and time required to pay to a developer to simplify or de-duplicate it. The interest is the decreased productivity of developers. Sometimes it’s impossible to refactor a duplicate code block but the aim should be to decrease as much technical debt. It helps to make your code of a higher quality.

Shotgun Surgery:

Suppose you write buggy code. You do a code review to find out the issue and then fix it. Now replace this scenario of buggy code with duplicate buggy code. You now have to fix every location that code is, losing your time, efficiency and sometimes temper. This situation is called inverse shotgun surgery and is pretty nasty for any developer.                                                              image showing Duplicate code removed with showing band-aid over the code

Increases security risks:

Alright, this is more of a copy and paste programming issue than duplicate code but like most times one produces repetitive code by using the copy-paste process it deserves a mention. When someone takes a code from somewhere and adds into their software they forget about the holes and endings that plagiarized code has. Duplicate codes leave an opening for attackers to exploit and get into your code making it vulnerable.

DRY Or Do not Repeat Yourself:

With serious risks and challenges involved with duplicate code, there is one renowned way of reducing it. Using DRY or Do not Repeat Yourself principle, you make sure that you stay away from duplicate code as often as you can. Rather you replace the duplicate code with abstractions or use data normalization. To reduce duplicity in a function, one can use loops and trees.

While DRY comes out as a system that can be applied for most types of duplicated codes, at some places it becomes a necessity to repeat. Like in many instances while using JAVA language. Hardcore coders also have problems maintaining the DRY principle because of their WET or We Enjoy Typing approach to programming. But even if you enjoy typing, the WET principle just translates to Waste Everyone’s Time to us.

CodeGrip will identify duplicated codes so you can make quality software

Hardcore coders are really difficult to find and trying to make distance with them because they write duplicate code may not be the right decision. Instead, use CodeGrip which is an automated code review tool that a developer can use. It scans your code to find duplicate lines and block of code from your GitHub or BitBucket repos. These duplications are shown as the percentage of code they cover to give you an overview. While the duplicated lines are highlighted under the issues tab and also your code. You can see the changes you perform and analyze the technical debt reduction as you refactor it. CodeGrip makes sure that your code is efficient, clean and duplicate free.

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