Recovering deleted branches in Git - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Recovering a recently deleted branch

You accidentally deleted a branch named feature-x. Which command will correctly restore it if the branch was deleted very recently and you know the branch's last commit is still in the reflog?

A git checkout -b feature-x $(git reflog show feature-x -1 | awk '{print $1}')

B git checkout -b feature-x refs/reflog/feature-x

C git checkout -b feature-x $(git reflog | head -1 | awk '{print $1}')

D git checkout -b feature-x $(git reflog | grep feature-x | head -1 | awk '{print $1}')

💡 Hint

Use git reflog show feature-x to access the branch-specific reflog and extract the most recent commit hash.

The command git reflog show feature-x -1 displays the most recent entry in the reflog for the feature-x branch reference, even after deletion. The first field is the commit hash of the branch tip. awk '{print $1}' extracts it, and git checkout -b recreates the branch at that commit.

🧠 Conceptual

intermediate

Understanding reflog for branch recovery

What does the git reflog command track that makes it useful for recovering deleted branches?

A It records all changes to the tip of branches and HEAD, including commits and checkouts.

B It tracks all remote branches and their statuses.

C It lists all files changed in the repository history.

D It shows the current status of the working directory and staging area.

💡 Hint

Think about what information helps find lost commits or branches.

git reflog records every change to HEAD and branch tips, including commits, checkouts, resets, and merges. This history allows you to find commits even if branches are deleted.

❓ Troubleshoot

advanced

Recovering a deleted branch when reflog is cleared

You deleted a branch bugfix and also ran git reflog expire --expire=now --all which cleared the reflog. What is the most reliable way to recover the branch now?

A Run <code>git checkout -b bugfix origin/bugfix</code> to restore from remote tracking branch.

B Run <code>git branch bugfix</code> to recreate the branch with the same name.

C Use <code>git reset --hard HEAD@{1}</code> to undo the deletion.

D Use <code>git fsck --lost-found</code> to find dangling commits and create the branch from the correct commit hash.

💡 Hint

Think about how to find commits not referenced by any branch or reflog.

git fsck --lost-found finds dangling commits that are not referenced by any branch or reflog. You can identify the commit for the deleted branch and recreate it. Other options either rely on remote branches or do not restore the commit.

🔀 Workflow

advanced

Steps to recover a deleted branch safely

Which sequence of commands correctly recovers a deleted branch release using reflog and then pushes it back to the remote repository?

A 2,4,1,3

B 2,1,4,3

C 2,1,3,4

D 1,2,4,3

💡 Hint

First find the commit, then create the branch, verify, and finally push.

First, use git reflog to find the commit hash. Then create the branch at that commit with git checkout -b release <commit-hash>. Next, verify the branch history with git log --oneline -5. Finally, push the recovered branch to the remote with git push origin release.

✅ Best Practice

expert

Preventing branch loss in collaborative projects

What is the best practice to avoid losing important branches accidentally in a shared Git repository?

A Avoid using branches and work only on the main branch to reduce complexity.

B Always delete branches locally and never push them to remote.

C Regularly push branches to remote and protect important branches with branch protection rules.

D Use <code>git gc</code> frequently to clean up old branches automatically.

💡 Hint

Think about collaboration and safety features in Git hosting services.

Pushing branches to remote ensures they are backed up. Branch protection rules prevent accidental deletion or force pushes on important branches. This practice helps teams avoid losing work.

Practice

1. What is the primary Git command used to find the commit hash of a recently deleted branch?

easy

A. git reflog

B. git branch -d

C. git reset --hard

D. git merge

Solution

1. Step 1: Understand the purpose of git reflog

   git reflog records all changes to the HEAD, including deleted branches.

2. Step 2: Identify the command that shows commit history including deleted refs

   git reflog lets you find the commit hash of the deleted branch.

3. Final Answer:

   git reflog -> Option A

4. Quick Check:

   Find deleted branch commit = git reflog [OK]

Hint: Use git reflog to find lost commits fast [OK]

Common Mistakes:

• Confusing git branch -d as recovery command
• Using git reset --hard which discards changes
• Thinking git merge recovers deleted branches

2. Which of the following commands correctly recreates a deleted branch named feature1 from a commit hash abc1234 and switches to it?

easy

A. git checkout -b feature1 abc1234

B. git reset feature1 abc1234

C. git branch feature1 abc1234

D. git checkout abc1234 feature1

Solution

1. Step 1: Understand the syntax to create a branch at a commit

   The correct syntax is git checkout -b [branch] [commit] to create and switch.

2. Step 2: Identify the correct command

   git checkout -b feature1 abc1234 creates branch feature1 at commit abc1234.

3. Final Answer:

   git checkout -b feature1 abc1234 -> Option A

4. Quick Check:

   Create branch at commit = git checkout -b branch commit [OK]

Hint: Use git checkout -b branch commit to restore branch [OK]

Common Mistakes:

• Using git checkout commit branch without -b
• Using git reset which does not create branches
• Using git branch without switching

3. After deleting a branch bugfix, you run git reflog and see this entry:

abc1234 HEAD@{2}: checkout: moving from bugfix to main

Which command will correctly restore the bugfix branch at that commit?

medium

A. git checkout bugfix

B. git branch -d bugfix abc1234

C. git reset --hard abc1234

D. git checkout -b bugfix abc1234

Solution

1. Step 1: Identify commit hash from reflog

   The commit hash abc1234 is where bugfix was last checked out.

2. Step 2: Use command to recreate branch at that commit

   git checkout -b bugfix abc1234 creates and switches to bugfix at that commit.

3. Final Answer:

   git checkout -b bugfix abc1234 -> Option D

4. Quick Check:

   Restore branch from commit = git checkout -b branch commit [OK]

Hint: Use reflog commit hash with git checkout -b [OK]

Common Mistakes:

• Using git branch -d which deletes branches
• Using git reset --hard which resets HEAD but not branches
• Trying git checkout bugfix without recreating branch

4. You tried to recover a deleted branch using git checkout -b feature abc123 but got an error: fatal: A branch named 'feature' already exists.
What is the best way to fix this?

medium

A. Use git checkout feature to switch to the existing branch

B. Delete the existing branch first with git branch -D feature then retry

C. Use git branch -b feature abc123 instead

D. Rename the commit hash to a new one

Solution

1. Step 1: Understand the error

   The error means branch feature already exists locally.

2. Step 2: Delete existing branch to recreate

   Use git branch -D feature to force delete the existing branch, then recreate it.

3. Final Answer:

   Delete existing branch with git branch -D feature then retry -> Option B

4. Quick Check:

   Delete conflicting branch before recreate [OK]

Hint: Delete existing branch with -D before recreating [OK]

Common Mistakes:

• Trying git branch -b which is invalid syntax
• Ignoring the existing branch and forcing checkout
• Renaming commit hash which is not possible

5. You accidentally deleted a branch release and want to recover it. You run git reflog and find multiple commits related to release. Which sequence of commands correctly recovers the branch at the latest commit and deletes the old branch pointer?

hard

A. git checkout -b release

B. git checkout release; git reset --hard

C. git branch -D release; git checkout -b release

D. git branch release

Solution

1. Step 1: Delete any existing branch pointer named release

   Use git branch -D release to remove old or conflicting branch references.

2. Step 2: Create a new branch release at the desired commit

   Use git checkout -b release <commit-hash> to recreate and switch to the branch at the correct commit.

3. Final Answer:

   git branch -D release; git checkout -b release <commit-hash> -> Option C

4. Quick Check:

   Delete old branch then recreate at commit [OK]

Hint: Delete old branch first, then recreate at commit [OK]

Common Mistakes:

• Using git checkout release when branch is deleted
• Using git reset --hard without recreating branch
• Using git branch release without switching