Code review in pull requests in Git - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of git command showing pull request status

What is the output of the following git command when checking the status of a pull request branch locally?

Git

git fetch origin pull/42/head:pr-42
 git checkout pr-42
 git status

A fatal: 'pull/42/head' does not appear to be a git repository

B

On branch pr-42
Your branch is up to date with 'pr-42'.
nothing to commit, working tree clean

C

On branch pr-42
Your branch is based on 'origin/main', but the upstream is gone.
nothing to commit, working tree clean

D

On branch pr-42
Your branch is ahead of 'origin/pr-42' by 1 commit.
nothing to commit, working tree clean

💡 Hint

Fetching a pull request creates a local branch named pr-42 tracking the PR head.

The command fetches the pull request number 42 into a local branch pr-42. Checking out pr-42 puts you on that branch. git status shows 'Your branch is up to date with 'pr-42'.'

🧠 Conceptual

intermediate

Purpose of code review in pull requests

What is the main purpose of performing a code review in a pull request?

A To check code quality, find bugs, and ensure standards before merging

B To deploy the code directly to production

C To automatically merge code changes without human intervention

D To delete the source branch after merging

💡 Hint

Think about why teams review code before merging.

Code review helps catch bugs, improve code quality, and maintain coding standards before merging changes into the main branch.

🔀 Workflow

advanced

Correct order of steps in a pull request review workflow

Arrange the steps in the correct order for a typical pull request code review workflow.

A 1,2,3,4

B 1,3,2,4

C 2,1,3,4

D 1,2,4,3

💡 Hint

Think about the natural flow from coding to review to update.

First, the developer creates and pushes code (1), then opens a pull request (2). The reviewer then comments (3), and the developer updates the PR (4).

❓ Troubleshoot

advanced

Error when merging pull request due to conflicts

You try to merge a pull request but get this error: "Merge conflict in file.txt". What should you do next?

A Delete the pull request and create a new one

B Force push the pull request branch to overwrite conflicts

C Fetch the latest main branch, merge it locally into the PR branch, resolve conflicts, then push

D Ignore the conflict and merge using --no-verify

💡 Hint

Conflicts mean changes clash and need manual fixing.

You must update the PR branch with the latest main branch, fix conflicts locally, then push the resolved code.

✅ Best Practice

expert

Ensuring accessibility in code review comments

Which practice best ensures accessibility when leaving code review comments on UI changes?

A Approve the PR without testing UI accessibility

B Only comment on code style and ignore UI accessibility

C Request the developer to add more animations for better UX

D Check color contrast, keyboard navigation, and ARIA labels in the UI code

💡 Hint

Accessibility means making UI usable for everyone.

Good code review includes checking UI accessibility features like color contrast, keyboard navigation, and ARIA labels.

Practice

1. What is the main purpose of a pull request in Git?

easy

A. To review and discuss code changes before merging

B. To delete a branch from the repository

C. To create a new repository

D. To reset the main branch to a previous commit

Solution

1. Step 1: Understand what a pull request does

   A pull request is used to propose code changes and get feedback before merging.

2. Step 2: Identify the main purpose

   It allows team members to review, discuss, and approve changes to keep code quality high.

3. Final Answer:

   To review and discuss code changes before merging -> Option A

4. Quick Check:

   Pull request = code review and discussion [OK]

Hint: Pull requests are for reviewing code before merging [OK]

Common Mistakes:

• Confusing pull requests with branch deletion
• Thinking pull requests create repositories
• Believing pull requests reset branches

2. Which Git command is used to push a new branch to the remote repository to start a pull request?

easy

A. git push origin main

B. git merge feature-branch

C. git pull origin feature-branch

D. git push origin feature-branch

Solution

1. Step 1: Identify the command to push a branch

   To push a new branch named 'feature-branch' to remote, use 'git push origin feature-branch'.

2. Step 2: Understand other options

   'git push origin main' pushes the main branch, 'git pull' fetches changes, and 'git merge' combines branches locally.

3. Final Answer:

   git push origin feature-branch -> Option D

4. Quick Check:

   Push new branch = git push origin branch-name [OK]

Hint: Push your feature branch with git push origin branch-name [OK]

Common Mistakes:

• Using git push origin main instead of feature branch
• Confusing git pull with git push
• Trying to merge before pushing the branch

3. Given this sequence of commands, what is the output of git status after step 4?

1. git checkout -b feature
2. touch newfile.txt
3. git add newfile.txt
4. git status

medium

A. On branch feature
Changes to be committed:
(new file: newfile.txt)

B. On branch feature
nothing to commit, working tree clean

C. On branch main
Changes to be committed:
(new file: newfile.txt)

D. fatal: not a git repository

Solution

1. Step 1: Analyze branch and file status

   After 'git checkout -b feature', you are on 'feature' branch. 'touch newfile.txt' creates a new file. 'git add newfile.txt' stages it.

2. Step 2: Understand git status output

   'git status' shows staged changes. Since newfile.txt is added, it appears under 'Changes to be committed' on branch 'feature'.

3. Final Answer:

   On branch feature Changes to be committed: (new file: newfile.txt) -> Option A

4. Quick Check:

   Added file staged = git status shows it [OK]

Hint: Staged files show under 'Changes to be committed' in git status [OK]

Common Mistakes:

• Assuming branch is still main
• Thinking staging clears changes
• Confusing untracked with staged files

4. You created a pull request but reviewers say your branch is behind main and has conflicts. What should you do to fix this?

medium

A. Delete your branch and create a new one

B. Force push your branch without updating

C. Merge main into your branch locally and resolve conflicts

D. Close the pull request and push directly to main

Solution

1. Step 1: Understand the conflict cause

   Your branch is behind main, so changes in main conflict with your branch.

2. Step 2: Fix conflicts by merging main

   Merge main into your branch locally using 'git merge main', resolve conflicts, then push updates to update the pull request.

3. Final Answer:

   Merge main into your branch locally and resolve conflicts -> Option C

4. Quick Check:

   Fix conflicts = merge main and resolve [OK]

Hint: Merge main into your branch to fix conflicts before pushing [OK]

Common Mistakes:

• Force pushing without resolving conflicts
• Deleting branch unnecessarily
• Pushing directly to main ignoring review

5. You want to ensure that every pull request is reviewed by at least two team members before merging. Which GitHub feature should you configure?

hard

A. Enable auto-merge on pull requests

B. Branch protection rules with required reviews

C. Set default branch to feature branch

D. Use git stash before pushing

Solution

1. Step 1: Identify the feature for enforcing reviews

   GitHub branch protection rules allow setting requirements like minimum number of reviewers before merging.

2. Step 2: Understand other options

   Auto-merge merges without review, changing default branch doesn't enforce reviews, and git stash is unrelated to pull requests.

3. Final Answer:

   Branch protection rules with required reviews -> Option B

4. Quick Check:

   Require reviews = branch protection rules [OK]

Hint: Use branch protection rules to require reviews before merge [OK]

Common Mistakes:

• Confusing auto-merge with review enforcement
• Changing default branch instead of protection rules
• Using git stash unrelated to reviews