Git Workflow for 42 School

A beginner-friendly guide to Git and GitHub workflows commonly used in 42 School projects.

This document explains: - branches - merge - pull - stash - reset - detached HEAD - GitHub workflow - common mistakes

Git is one of the most important tools for software development.

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What is Git?

Git is a version control system.

It tracks: - code changes - project history - branches - collaboration

Git allows developers to: - work safely - undo mistakes - collaborate efficiently

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What is GitHub?

GitHub is an online platform that hosts Git repositories.

GitHub allows: - remote backups - collaboration - pull requests - code sharing

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Basic Git Workflow

Most workflows follow this pattern:

Write code
→ git add
→ git commit
→ git push

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Repository

A repository (repo) stores: - project files - commit history - branches

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Initializing a Repository

git init

Creates a local Git repository.

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Checking Repository Status

git status

One of the most important commands.

Shows: - modified files - staged files - current branch

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Adding Files

git add file.py

Adds a file to the staging area.

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Add Everything

git add .

Stages all modified files.

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Commit

A commit is a saved snapshot of the project.

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Creating a Commit

git commit -m "Added BFS solver"

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Good Commit Messages

Good:

Added config parser validation

Bad:

fix

Clear messages improve project history.

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Branches

Branches allow separate development paths.

Useful for: - new features - experiments - bug fixes

Without affecting the main project.

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Viewing Branches

git branch

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Creating a Branch

git branch feature-menu

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Switching Branches

git checkout feature-menu

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Modern Alternative

git switch feature-menu

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Create + Switch Together

git checkout -b feature-menu

or:

git switch -c feature-menu

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Why Branches Matter

Branches help: - isolate work - avoid breaking main - support teamwork

Very important in 42 group projects.

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Merge

Merge combines branches together.

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Example Workflow

main
└── feature-menu

After development:

git checkout main
git merge feature-menu

This brings: - feature-menu changes - into main

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Merge Conflicts

Conflicts happen when: - two branches modify the same lines

Git cannot decide automatically.

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Conflict Example

<<<<<<< HEAD
old code
=======
new code
>>>>>>> feature

You must: - edit manually - choose correct code - remove conflict markers

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pull

git pull downloads updates from GitHub.

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Example

git pull

Equivalent to:

git fetch
git merge

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Why Pull Matters

Always pull before: - pushing - merging - starting work

Especially in team projects.

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push

Uploads local commits to GitHub.

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Example

git push

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First Push of New Branch

git push -u origin feature-menu

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origin

origin usually means: - the GitHub repository

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stash

git stash temporarily saves unfinished work.

Very useful when: - changing branches - pulling updates - testing another branch

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Example

git stash

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Restoring Stash

git stash pop

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Viewing Stashes

git stash list

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reset

git reset moves commits or unstages changes.

Dangerous if used incorrectly.

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Unstage Files

git reset

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Reset to Previous Commit

git reset --hard HEAD~1

Removes: - last commit - changes permanently

Be careful.

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Soft Reset

git reset --soft HEAD~1

Removes commit: - keeps file changes

Safer than --hard.

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Detached HEAD

A detached HEAD means: - Git is not on a branch - you are viewing a specific commit

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Common Cause

git checkout abc123

Where: - abc123 is a commit hash

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Why Detached HEAD is Dangerous

Commits made here may become lost.

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Fix Detached HEAD

Return to a branch:

git checkout main

or:

git switch main

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Clone Repository

Downloads a GitHub repository locally.

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Example

git clone https://github.com/user/project.git

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GitHub Workflow for 42

Common workflow:

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Step 1

Clone project:

git clone REPOSITORY_URL

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Step 2

Enter project:

cd project

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Step 3

Create branch:

git checkout -b sara-feature

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Step 4

Work normally.

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Step 5

Add files:

git add .

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Step 6

Commit:

git commit -m "Added MLX rendering"

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Step 7

Push branch:

git push -u origin sara-feature

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Step 8

Merge later into main.

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Common 42 Problems

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"Your branch has diverged"

Means: - local and remote history differ

Usually fixed with:

git pull

or: - merge/rebase

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"nothing to commit"

Means: - no modified files exist

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Accidentally Working on main

Very common mistake.

Fix: - create branch - move work there

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Detached HEAD Confusion

Students often checkout commits directly.

Always verify current branch:

git branch

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Pull Before Push

Always:

git pull
git push

Especially in teams.

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Useful Commands Summary

Command	Purpose
git status	View repository state
git add	Stage files
git commit	Save snapshot
git push	Upload to GitHub
git pull	Download updates
git branch	View branches
git checkout	Switch branches
git stash	Temporarily save work
git reset	Undo/reset changes

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Recommended .gitignore

Do not upload: - virtual environments - cache files - compiled Python files

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Example

venv/
__pycache__/
*.pyc

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Best Practices

• Commit frequently
• Use meaningful commit messages
• Pull before pushing
• Avoid working directly on main
• Use branches for features
• Verify branch before committing
• Avoid dangerous reset commands unless necessary

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Good Branch Names

Good:

feature-menu
mlx-renderer
config-parser

Bad:

test
stuff
aaa

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Final Notes

Git is an essential skill for modern software development.

Strong Git knowledge helps: - teamwork - debugging - project organization - safer development - version tracking

Git becomes especially important in: - 42 group projects - MLX projects - large codebases - collaborative development

Understanding Git deeply will save countless hours during development.

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