Lab Assignment: Resolving Merge Conflicts

Overview

In this lab, you will practice resolving merge conflicts. When you merge one branch into the other, Git will be forced to ask you to resolve the conflict manually.

Get start

reference: https://graphite.dev/guides/git-clone-all-branches

Fork this repo to your own GitHub account, and remember to un-check the Copy the main branch only option.

Ensure your repo has all three branches main, branchA, and branchB.

Clone your repo to local using git clone

Check your local branch using git branch, you might find there's only one main branch available locally.

Check the remote branches using git branch -r, you will find

  origin/HEAD -> origin/main
  origin/branchA
  origin/branchB
  origin/main

We also want to track other remote branches.

We can checkout branches locally by

git checkout -b <branch-name> origin/<branch-name>

or we can automate this process and checkout all remote branches using a loop in command line:

for branch in `git branch -r | grep -v '\->'`; do
    git branch --track "${branch#origin/}" "$branch"
done

After setting up tracking for each branch, make sure your local copies are up to date:

git fetch --all

Now we are ready to start our lab

Lab Steps

Merge branchB into branchA (three-way merge with conflict)

• Switch to branchA using git checkout branchA
• run command git diff branchA branchB main.txt, you will find the branchA and branchB's main.txt are different:

diff --git a/main.txt b/main.txt
index 6d58650..d096ad8 100644
--- a/main.txt
+++ b/main.txt
@@ -1 +1 @@
-Hello from Branch A
+Hello from Branch B

• First, make sure you are in branchA.
• Merge branchB into branchA using git merge branchB. This merge will trigger a merge conflict since branchA and branchB diverged from the initial commit, and the two branches changed the same part of the same file differently
• Open main.txt and look for conflict markers (<<<<<<<, =======, >>>>>>>).
• Manually edit the file to resolve the conflict, then stage and commit your changes.
• You will receive a message like [branchA 9c33a47] Merge branch 'branchB' into branchA

Merge branchA into main (three-way merge)

• Switch to main.
• run command git diff main branchA main.txt, you will find the main and branchA's main.txt are different.
• Merge branchA into main. Note branchA and main diverged from the initial commit, but there's no conflict even if the the file main.txt is different. Why?

Key Commands

• Initialize Repository:

  git init

• Create and Switch Branches:

  git checkout -b <branch-name>
  git checkout <branch-name>

• Add and Commit Changes:

  git add <file>
  git commit -m "Your commit message"

• Merge Branches:

  git merge <branch-name>

Resolving Conflicts

1. Edit the file to remove conflict markers.
2. Stage the resolved file: git merge <branch-name>
3. Commit the merge resolution: git commit -m "Resolved merge conflict"