Git Merge Conflict Resolution

Git Merge Conflict Resolution

Trigger: Use when resolving a merge conflict during git merge, git rebase, git pull, or git cherry-pick.

Understanding Conflict Markers

<<<<<<< HEAD
code from your current branch
=======
code from the incoming branch
>>>>>>> feature-branch

• HEAD = your current branch (what you had)
• ======= = divider
• incoming = the branch you're merging in

Resolution Workflow

1. Identify Conflicting Files

# After a failed merge/rebase:
git status                            # Shows conflicting files (both modified)
git diff                              # Shows conflict markers
git diff --name-only --diff-filter=U  # Unmerged files only

2. Choose Your Resolution Strategy

A) Manual (best for understanding):

# Edit files to resolve conflicts, remove markers, keep desired code
git add <file>
git commit                            # For merge
git rebase --continue                 # For rebase

B) Accept one side entirely:

# Keep your version (HEAD)
git checkout --ours -- <file>
git add <file>

# Keep their version (incoming)
git checkout --theirs -- <file>
git add <file>

C) Interactive merge tool:

git mergetool                         # Opens configured tool (vimdiff, VS Code, etc.)
# Common tools:  meld, kdiff3, vimdiff, code --wait

3. Complete the Operation

Prevention

# Pull with rebase to avoid merge bubbles
git config --global pull.rebase true

# Before merging, review the diff
git merge --no-commit --no-ff feature  # Stage without committing
git diff --cached                       # Review what will land
git merge --abort                       # Or proceed with git commit

# Use rerere (reuse recorded resolution)
git config --global rerere.enabled true

Complex Scenarios

Binary file conflicts: Cannot be merged — choose one side with --ours/--theirs

Multiple conflicts in rebase: Each commit in the rebase can have its own conflicts

git rebase main
# Fix conflicts, git add, then:
git rebase --continue
# Repeat until all commits are rebased
# Or: git rebase --skip (skip current commit)
# Or: git rebase --abort (undo everything)

Conflict in deleted/modified file: git add/rm <file> then continue

Pitfalls

• Accidental markers: Search for leftover <<<<<<<, =======, >>>>>>> in final diff
• Whitespace conflicts: git merge -Xignore-space-change for formatting-only diffs
• Merge --abort loses uncommitted work: Stash before risky merges
• Rebase overwrites commit history: Only rebase local/private branches

Verification

git log --oneline --graph --all                # Check history shape
git diff main...HEAD                           # Verify merge introduced correct changes
grep -rn "^<<<<<<< \|^=======$\|^>>>>>>> " .   # No leftover markers