debian-mirror-gitlab/doc/university/training/topics/merge_conflicts.md

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Merge conflicts

• Happen often
• Learning to fix conflicts is hard
• Practice makes perfect
• Force push after fixing conflicts. Be careful!

Merge conflicts sample workflow

1. Checkout a new branch and edit conflicts.rb. Add 'Line4' and 'Line5'.
2. Commit and push.
3. Checkout master and edit conflicts.rb. Add 'Line6' and 'Line7' below 'Line3'.
4. Commit and push to master.
5. Create a merge request and watch it fail.
6. Rebase our new branch with master.
7. Fix conflicts on the conflicts.rb file.
8. Stage the file and continue rebasing.
9. Force push the changes.
10. Finally continue with the Merge Request.

git checkout -b conflicts_branch

# vi conflicts.rb
# Add 'Line4' and 'Line5'

git commit -am "add line4 and line5"
git push origin conflicts_branch

git checkout master

# vi conflicts.rb
# Add 'Line6' and 'Line7'
git commit -am "add line6 and line7"
git push origin master

Create a merge request on the GitLab web UI. You'll see a conflict warning.

git checkout conflicts_branch
git fetch
git rebase master

# Fix conflicts by editing the files.

git add conflicts.rb
# No need to commit this file

git rebase --continue

# Remember that we have rewritten our commit history so we
# need to force push so that our remote branch is restructured
git push origin conflicts_branch -f

Note

• When to use git merge and when to use git rebase
• Rebase when updating your branch with master
• Merge when bringing changes from feature to master
• Reference: https://www.atlassian.com/git/tutorials/merging-vs-rebasing