Code Smell 239 - Big Pull Request

You make too many different changes in a single pull request

TL;DR: Always stick to baby steps

Problems

• Readability
• Code Review time and complexity
• Merge Conflicts
• Testing Challenges

Solutions

1. Break the change in atomic parts

Context

When pull requests become very large, they can pose several challenges and problems for development teams.

You must avoid merge requests making different unrelated changes.

Sample Code

Wrong

function generateFibonacci(ordinal) {
  const fibonacciSequence = [0, 1];

  for (let index = index; index < ordinal; index++) {
    const nextFibonacci = fibonacciSequence[index - 1]
          + fibonacciSequence[index - 2];
    fibonacciSequence.push(nextFibonacci);
  }

  return fibonacciSequence;
}

// This function solves a very different problem
// You should not mix them in a single pull request

function voyagerDistanceFromEarth(currentDistanceInKms, yearsTravelled) {
  const speedOfVoyagerInKmS = 17; 

  return currentDistanceInKms + 
        speedOfVoyagerInKmS * yearsTravelled * 60 * 60 * 24 * 365.25;
}

Right

function generateFibonacci(ordinal) {
  const fibonacciSequence = [0, 1];

  for (let index = index; index < ordinal; index++) {
    const nextFibonacci = fibonacciSequence[index - 1]
          + fibonacciSequence[index - 2];
    fibonacciSequence.push(nextFibonacci);
  }

  return fibonacciSequence;
}

// You break it into two different pull requests

Detection

• Automatic: You can put a threshold and a warning on big merge requests.

Exceptions

• Big refactors that cannot be made with baby steps

Tags

• Complexity

Level

Beginner

AI Assistants

AI assistants do not create pull requests.

They generate the code you need.

Conclusion

Software engineers must be experts at managing (and avoiding) accidental complexity.

Relations

Code Smell 170 - Refactor with Functional Changes

Disclaimer

Code Smells are my opinion.

Credits

Photo by Håkon Grimstad on Unsplash

First make the change easy (warning: this might be hard), then make the easy change.

Kent Beck

Software Engineering Great Quotes

This article is part of the CodeSmell Series.

How to Find the Stinky Parts of your Code