Git Notes

Hub Benefits of Git and GitHub - Why They Matter Git vs GitHub Version Control System What Is Git What Is GitHub Configure Git - User Identity and Settings Create GitHub Account - Sign Up Guide First Git Repository - Getting Started Install Git on Linux - Complete Setup Guide Install Git on macOS - Installation Guide Install Git on Windows - Step-by-Step Guide Git Add - Stage Changes Git Clone - Copy Remote Repositories Locally Git Commit - Save Changes Git Diff - Compare Changes in Your Repository Git Ignore - Exclude Files from Version Control Git Init - Initialize Repository Git Log - View Commit History Git Status - Check Repository State Git Fetch - Download Remote Changes Without Merging Git Pull - Fetch and Merge Remote Changes Git Push - Upload Local Commits to Remote Repository Git Remote - Manage Remote Repository Connections Local Repository - Understanding Your Git Working Environment Remote Repository - Collaborate Through Shared Repositories Sync Local and Remote - Keep Repositories in Harmony Amend Commit - Fix Last Commit Delete Branch - Clean Up Branches Git Reset - Move HEAD and Undo Commits Git Restore - Discard Changes Git Revert - Safely Undo Changes Recover Lost Commits - Reflog Guide Fork Repository GitHub Pages GitHub Profile Setup GitHub Repositories GitHub Stars and Watchers Repository Settings Code Reviews Git Clone Git Fetch Git Pull Git Push GitHub Issues Labels and Milestones Open Source Contributions GitHub Project Boards Pull Requests - Propose and Review Code Changes Team Collaboration with Git and GitHub Automated Testing with GitHub Actions CI/CD with GitHub Actions Deployment Automation with GitHub Actions Introduction to GitHub Actions GitHub Actions Runners GitHub Actions Workflows Enterprise Git Workflows - Scale Git for Large Organizations Feature Branch Workflow - Isolate Development Work GitFlow Workflow - Structured Release Management Monorepo Workflow - Manage Multiple Projects in One Repository Trunk-Based Development - Ship Code Fast and Safely Deployment Workflows GitHub Pages Deployment Netlify Deployment from GitHub Render Deployment from GitHub Vercel Deployment from GitHub Branch Protection Rules - Secure Your Git Branches Personal Access Tokens - Authenticate with GitHub Repository Security Best Practices Secret Scanning - Detect Leaked Credentials in Code Signed Commits - Verify Commit Authenticity with GPG SSH Keys - Secure Git Authentication Without Passwords Git Bisect - Find Bugs with Binary Search Git Cherry-Pick - Apply Specific Commits to Any Branch Git Hooks - Automate Workflows with Git Events Git Internals - Understanding How Git Works Under the Hood Git Stash - Temporarily Save Uncommitted Changes Git Submodules - Manage External Dependencies as Git Repos Git Tag - Mark Important Points in History Git Worktrees - Work on Multiple Branches Simultaneously Collaborative Web App Project Complete Team Workflow Project GitHub Actions Project - Build a CI/CD Pipeline Open Source Project Contribution - Guided Exercise Portfolio Project with Git - Showcase Your Skills Git Command Cheatsheet Git Interview Questions - Comprehensive Preparation Guide GitHub Interview Questions Scenario-Based Git Interview Questions Git Troubleshooting Guide Git Best Practices - Professional Development Habits Common Git Errors and Fixes - Quick Solutions Git Command Reference - Complete Command Guide Learning Resources - Continue Your Git & GitHub Education Branch Strategies - Choosing the Right Git Branching Model Create Branch in Git - Start New Development Lines Fast-Forward Merge in Git - Clean Linear History Git Branch Git Checkout Git Merge Git Rebase Merge Branches in Git - Combine Development Work Merge Conflicts - Resolve Git Conflicts Like a Pro Switch Branch in Git - Navigate Between Branches

Merge Conflicts - Resolve Git Conflicts Like a Pro

Learn how to identify, understand, and resolve merge conflicts in Git. Master conflict resolution strategies, tools, and prevention techniques.

Merge conflicts occur when Git cannot automatically combine changes from different branches because both branches modified the same lines in a file. Understanding how to resolve conflicts efficiently is essential for team collaboration.

When Do Conflicts Happen?

Conflicts arise when:

Two branches edit the same line(s) in the same file
One branch deletes a file that another branch modified
Both branches add a file with the same name but different content

main	line 1: "Hello World" ← Changed to "Hello Everyone"
feature	line 1: "Hello World" ← Changed to "Hi World"
Git cannot decide which change to keep	CONFLICT

Conflict Markers Explained

When a conflict occurs, Git marks the conflicting sections in the file:

Code example

<<<<<<< HEAD
const greeting = "Hello Everyone";
=======
const greeting = "Hi World";
>>>>>>> feature/update-greeting

Marker	Meaning
`<<<<<<< HEAD`	Start of YOUR branch's version (current branch)
`=======`	Separator between the two versions
`>>>>>>> branch-name`	End of THEIR branch's version (incoming branch)

Creating a Conflict (Tutorial)

bash example

# Setup
git init conflict-demo && cd conflict-demo
echo "Hello World" > greeting.txt
git add . && git commit -m "Initial greeting"

# Create a feature branch and modify the file
git checkout -b feature/update
echo "Hi Universe" > greeting.txt
git add . && git commit -m "Update greeting to Universe"

# Go back to main and make a different change
git checkout main
echo "Hello Everyone" > greeting.txt
git add . && git commit -m "Update greeting to Everyone"

# Try to merge - CONFLICT!
git merge feature/update

Output

Auto-merging greeting.txt
CONFLICT (content): Merge conflict in greeting.txt
Automatic merge failed; fix conflicts and then commit the result.

Resolving Conflicts Step by Step

Step 1: Identify Conflicted Files

bash example

git status

Output

On branch main
You have unmerged paths.
  (fix conflicts and run "git commit")
  (use "git merge --abort" to abort the merge)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
        both modified:   greeting.txt

no changes added to commit (use "git add" to track)

Step 2: Open and Edit the Conflicted File

bash example

cat greeting.txt

Output

<<<<<<< HEAD
Hello Everyone
=======
Hi Universe
>>>>>>> feature/update

Edit the file to resolve — choose one version, combine them, or write something new:

bash example

# Option A: Keep current branch (HEAD)
echo "Hello Everyone" > greeting.txt

# Option B: Keep incoming branch
echo "Hi Universe" > greeting.txt

# Option C: Combine both changes
echo "Hello Everyone in the Universe" > greeting.txt

Step 3: Mark as Resolved

bash example

git add greeting.txt

Step 4: Complete the Merge

bash example

git commit
# Or with a message:
git commit -m "Resolve merge conflict in greeting.txt"

Output

[main f8e7d6c] Resolve merge conflict in greeting.txt

Complex Conflict Example

Example

// File with conflict markers: function calculateTotal(items) { <<<<<<< HEAD const tax = 0.08; const shipping = items.length > 5 ? 0 : 5.99; return items.reduce((sum, item) => sum + item.price, 0) * (1 + tax) + shipping; ======= const discount = items.length > 3 ? 0.1 : 0; const subtotal = items.reduce((sum, item) => sum + item.price, 0); return subtotal * (1 - discount); >>>>>>> feature/add-discount }

Resolved version (incorporating both changes):

Example

function calculateTotal(items) { const tax = 0.08; const shipping = items.length > 5 ? 0 : 5.99; const discount = items.length > 3 ? 0.1 : 0; const subtotal = items.reduce((sum, item) => sum + item.price, 0); return subtotal * (1 - discount) * (1 + tax) + shipping; }

Using Merge Tools

Configure a Merge Tool

bash example

# Set VS Code as merge tool
git config --global merge.tool vscode
git config --global mergetool.vscode.cmd "code --wait --merge $REMOTE $LOCAL $BASE $MERGED"

# Use the merge tool
git mergetool

Built-in Conflict Resolution

bash example

# Accept current branch version for all conflicts
git checkout --ours filename.txt

# Accept incoming branch version for all conflicts
git checkout --theirs filename.txt

# After choosing, mark as resolved
git add filename.txt

Resolve All Files at Once

bash example

# Accept all changes from current branch
git checkout --ours .
git add .

# Accept all changes from incoming branch
git checkout --theirs .
git add .

Aborting a Merge

If you want to cancel the merge entirely:

bash example

# Before committing
git merge --abort

# After committing (revert the merge)
git revert -m 1 HEAD

Preventing Conflicts

Keep Branches Short-Lived

bash example

# Regularly update your feature branch
git checkout feature/my-work
git rebase main  # or git merge main

Communicate with Your Team

Coordinate who works on which files
Break large files into smaller modules
Use feature flags instead of long-lived branches

Use .gitattributes for Binary Files

bash example

# .gitattributes
*.png binary
*.jpg binary
*.pdf binary
# These files use "ours" strategy - keep current version
database.sqlite merge=ours

Conflict During Rebase

Conflicts during rebase are resolved differently:

bash example

git rebase main

Output

CONFLICT (content): Merge conflict in app.js
error: could not apply a1b2c3d... Add feature

bash example

# Resolve the conflict in app.js
git add app.js

# Continue rebasing (NOT git commit)
git rebase --continue

# Or abort
git rebase --abort

Common Conflict Scenarios

Deleted vs Modified

bash example

CONFLICT (modify/delete): file.txt deleted in feature and modified in HEAD.

bash example

# Keep the file
git add file.txt

# Accept deletion
git rm file.txt

Both Added (Same Filename)

bash example

CONFLICT (add/add): Merge conflict in newfile.txt

Both branches created a file with the same name — edit it to combine content.

Renamed vs Modified

bash example

CONFLICT (rename/delete): oldname.txt renamed to newname.txt in feature,
but deleted in HEAD.

Interview Questions

What causes a merge conflict in Git?

A merge conflict occurs when two branches modify the same line(s) in the same file, when one branch deletes a file another modified, or when both branches add a file with the same name but different content.

How do you resolve a merge conflict?

Open the conflicted file, find the conflict markers (<<<, ===, >>>), decide which changes to keep, remove the markers, save the file, stage it with git add, and complete with git commit.

What is the difference between --ours and --theirs?

--ours keeps the version from the current branch (the one you are ON). --theirs keeps the version from the branch being merged in. During rebase, these are reversed.

How can you prevent merge conflicts?

Keep branches short-lived, regularly rebase/merge from main, communicate with team about file ownership, break large files into smaller ones, and use feature flags.

What happens when you run git merge --abort?

It cancels the in-progress merge and restores the branch to its state before the merge was attempted. All conflict markers and partially merged changes are discarded.

Exam Focus

Revise definitions, diagrams, examples, and short-answer points for Merge Conflicts - Resolve Git Conflicts Like a Pro.

Interview Use

Prepare one clear explanation, one practical example, and one common mistake for this Git & GitHub topic.

Search Terms

git-github, git & github, git, github, branching, and, merging, merge

Related Git & GitHub Topics

Continue learning this concept

Branching And MergingFast-Forward Merge in Git - Clean Linear HistoryUnderstand fast-forward merges in Git, when they happen, how they differ from three-way merges, and how to control merge behavior with --no-ff and --ff-only flags.Branching And MergingGit MergeMerging is the process of combining the work from two different branches into one. It is how features developed in isolation come together to form a...Branching And MergingMerge Branches in Git - Combine Development WorkLearn how to merge branches in Git including three-way merges, merge strategies, and best practices for combining feature branches into main development lines.Branching And MergingBranch Strategies - Choosing the Right Git Branching ModelExplore popular Git branching strategies including GitFlow, GitHub Flow, and trunk-based development. Learn when to use each strategy for your team and project.Branching And MergingCreate Branch in Git - Start New Development LinesLearn how to create branches in Git for feature development, bug fixes, and experimentation. Understand branch creation from different starting points.Branching And MergingGit BranchBranching is one of the most powerful features in Git, and understanding how to work with branches effectively is what separates a beginner from a...

PreviousMerge Branches in Git - Combine Development Work NextSwitch Branch in Git - Navigate Between Branches

Git Notes

Merge Conflicts - Resolve Git Conflicts Like a Pro

Learn how to identify, understand, and resolve merge conflicts in Git. Master conflict resolution strategies, tools, and prevention techniques.

When Do Conflicts Happen?

Conflicts arise when:

Two branches edit the same line(s) in the same file
One branch deletes a file that another branch modified
Both branches add a file with the same name but different content

main	line 1: "Hello World" ← Changed to "Hello Everyone"
feature	line 1: "Hello World" ← Changed to "Hi World"
Git cannot decide which change to keep	CONFLICT

Conflict Markers Explained

When a conflict occurs, Git marks the conflicting sections in the file:

Code example

<<<<<<< HEAD
const greeting = "Hello Everyone";
=======
const greeting = "Hi World";
>>>>>>> feature/update-greeting

Marker	Meaning
`<<<<<<< HEAD`	Start of YOUR branch's version (current branch)
`=======`	Separator between the two versions
`>>>>>>> branch-name`	End of THEIR branch's version (incoming branch)

Creating a Conflict (Tutorial)

bash example

# Setup
git init conflict-demo && cd conflict-demo
echo "Hello World" > greeting.txt
git add . && git commit -m "Initial greeting"

# Create a feature branch and modify the file
git checkout -b feature/update
echo "Hi Universe" > greeting.txt
git add . && git commit -m "Update greeting to Universe"

# Go back to main and make a different change
git checkout main
echo "Hello Everyone" > greeting.txt
git add . && git commit -m "Update greeting to Everyone"

# Try to merge - CONFLICT!
git merge feature/update

Output

Auto-merging greeting.txt
CONFLICT (content): Merge conflict in greeting.txt
Automatic merge failed; fix conflicts and then commit the result.

Resolving Conflicts Step by Step

Step 1: Identify Conflicted Files

bash example

git status

Output

On branch main
You have unmerged paths.
  (fix conflicts and run "git commit")
  (use "git merge --abort" to abort the merge)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
        both modified:   greeting.txt

no changes added to commit (use "git add" to track)

Step 2: Open and Edit the Conflicted File

bash example

cat greeting.txt

Output

<<<<<<< HEAD
Hello Everyone
=======
Hi Universe
>>>>>>> feature/update

Edit the file to resolve — choose one version, combine them, or write something new:

bash example

# Option A: Keep current branch (HEAD)
echo "Hello Everyone" > greeting.txt

# Option B: Keep incoming branch
echo "Hi Universe" > greeting.txt

# Option C: Combine both changes
echo "Hello Everyone in the Universe" > greeting.txt

Step 3: Mark as Resolved

bash example

git add greeting.txt

Step 4: Complete the Merge

bash example

git commit
# Or with a message:
git commit -m "Resolve merge conflict in greeting.txt"

Output

[main f8e7d6c] Resolve merge conflict in greeting.txt

Complex Conflict Example

Example

Resolved version (incorporating both changes):

Example

Using Merge Tools

Configure a Merge Tool

bash example

# Set VS Code as merge tool
git config --global merge.tool vscode
git config --global mergetool.vscode.cmd "code --wait --merge $REMOTE $LOCAL $BASE $MERGED"

# Use the merge tool
git mergetool

Built-in Conflict Resolution

bash example

# Accept current branch version for all conflicts
git checkout --ours filename.txt

# Accept incoming branch version for all conflicts
git checkout --theirs filename.txt

# After choosing, mark as resolved
git add filename.txt

Resolve All Files at Once

bash example

# Accept all changes from current branch
git checkout --ours .
git add .

# Accept all changes from incoming branch
git checkout --theirs .
git add .

Aborting a Merge

If you want to cancel the merge entirely:

bash example

# Before committing
git merge --abort

# After committing (revert the merge)
git revert -m 1 HEAD

Preventing Conflicts

Keep Branches Short-Lived

bash example

# Regularly update your feature branch
git checkout feature/my-work
git rebase main  # or git merge main

Communicate with Your Team

Coordinate who works on which files
Break large files into smaller modules
Use feature flags instead of long-lived branches

Use .gitattributes for Binary Files

bash example

# .gitattributes
*.png binary
*.jpg binary
*.pdf binary
# These files use "ours" strategy - keep current version
database.sqlite merge=ours

Conflict During Rebase

Conflicts during rebase are resolved differently:

bash example

git rebase main

Output

CONFLICT (content): Merge conflict in app.js
error: could not apply a1b2c3d... Add feature

bash example

# Resolve the conflict in app.js
git add app.js

# Continue rebasing (NOT git commit)
git rebase --continue

# Or abort
git rebase --abort

Common Conflict Scenarios

Deleted vs Modified

bash example

CONFLICT (modify/delete): file.txt deleted in feature and modified in HEAD.

bash example

# Keep the file
git add file.txt

# Accept deletion
git rm file.txt

Both Added (Same Filename)

bash example

CONFLICT (add/add): Merge conflict in newfile.txt

Both branches created a file with the same name — edit it to combine content.

Renamed vs Modified

bash example

CONFLICT (rename/delete): oldname.txt renamed to newname.txt in feature,
but deleted in HEAD.

Interview Questions

What causes a merge conflict in Git?

How do you resolve a merge conflict?

Open the conflicted file, find the conflict markers (<<<, ===, >>>), decide which changes to keep, remove the markers, save the file, stage it with git add, and complete with git commit.

What is the difference between --ours and --theirs?

--ours keeps the version from the current branch (the one you are ON). --theirs keeps the version from the branch being merged in. During rebase, these are reversed.

How can you prevent merge conflicts?

Keep branches short-lived, regularly rebase/merge from main, communicate with team about file ownership, break large files into smaller ones, and use feature flags.

What happens when you run git merge --abort?

It cancels the in-progress merge and restores the branch to its state before the merge was attempted. All conflict markers and partially merged changes are discarded.

Exam Focus

Revise definitions, diagrams, examples, and short-answer points for Merge Conflicts - Resolve Git Conflicts Like a Pro.

Interview Use

Prepare one clear explanation, one practical example, and one common mistake for this Git & GitHub topic.

Search Terms

git-github, git & github, git, github, branching, and, merging, merge

Related Git & GitHub Topics

Continue learning this concept

PreviousMerge Branches in Git - Combine Development Work NextSwitch Branch in Git - Navigate Between Branches