pre-push hook in Git - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this pre-push hook script?

Given this simple pre-push hook script, what will be the output when you try to push?

Git

#!/bin/sh

echo "Running pre-push checks..."
exit 1

A Push is blocked with message: pre-push hook failed

B Push is blocked with message: Running pre-push checks...

C Push succeeds silently with no output

D Push succeeds but prints Running pre-push checks...

💡 Hint

Remember that exit 1 in a hook stops the push.

The script prints the message and exits with status 1, which blocks the push and shows the message.

🧠 Conceptual

intermediate

What is the main purpose of a pre-push hook in Git?

Choose the best description of what a pre-push hook does.

A It runs before pushing to validate or block the push

B It automatically merges branches before pushing

C It runs after the push completes to notify the user

D It deletes remote branches after pushing

💡 Hint

Think about when the hook runs relative to the push action.

A pre-push hook runs before the push to check conditions and can block the push if needed.

❓ Troubleshoot

advanced

Why does this pre-push hook not block the push?

This pre-push hook script is supposed to block pushes if tests fail, but pushes always succeed. Why?

Git

#!/bin/sh

./run_tests.sh
exit 0

A Git hooks cannot block pushes

B The run_tests.sh script is not executable

C The script always exits with 0, so push is never blocked

D The hook file is not named correctly

💡 Hint

Check the exit code of the hook script.

The hook script exits with 0 regardless of test results, so Git allows the push.

🔀 Workflow

advanced

In which directory should you place a pre-push hook script?

Where do you put a pre-push hook script so Git runs it automatically?

A .git/hooks/pre-push

B root directory of the project

C any directory named hooks anywhere

D .git/pre-push

💡 Hint

Git looks for hooks in a specific folder inside the .git directory.

Git runs hooks placed in the .git/hooks directory with the exact hook name.

✅ Best Practice

expert

What is the best way to share a pre-push hook with your team?

You want all team members to use the same pre-push hook. What is the best practice?

A Use a global Git hook configured on each developer's machine

B Ask each member to manually create the hook in their .git/hooks folder

C Put the hook script in the root directory and rely on Git to find it automatically

D Commit the hook script inside the repository and add a setup script to copy it to .git/hooks

💡 Hint

Git does not track .git/hooks folder contents.

Since .git/hooks is not versioned, committing the hook script and providing a setup script ensures consistent hooks.

Practice

1. What is the main purpose of a pre-push hook in Git?

easy

A. To delete local branches after pushing

B. To merge branches automatically before pushing

C. To run checks or tests before code is pushed to a remote repository

D. To create a backup of the repository before pushing

Solution

1. Step 1: Understand the role of pre-push hooks

   Pre-push hooks run scripts before pushing code to a remote repository to catch errors early.

2. Step 2: Identify the correct purpose

   They help ensure code quality by running tests or checks before the push happens.

3. Final Answer:

   To run checks or tests before code is pushed to a remote repository -> Option C

4. Quick Check:

   Pre-push hook = run checks before push [OK]

Hint: Pre-push hooks run before push to catch problems early [OK]

Common Mistakes:

• Confusing pre-push with post-push hooks
• Thinking it merges branches automatically
• Assuming it deletes branches

2. Which of the following is the correct way to make a pre-push hook script executable on Linux or macOS?

easy

A. chmod +x .git/hooks/pre-push

B. git enable pre-push

C. chmod 777 .git/hooks/pre-push

D. git hook activate pre-push

Solution

1. Step 1: Identify how to make scripts executable

   On Linux/macOS, chmod +x sets execute permission on a file.

2. Step 2: Apply to pre-push hook

   Running chmod +x .git/hooks/pre-push makes the hook script runnable by Git.

3. Final Answer:

   chmod +x .git/hooks/pre-push -> Option A

4. Quick Check:

   Make hook executable = chmod +x [OK]

Hint: Use chmod +x to make hook scripts executable [OK]

Common Mistakes:

• Using git commands that don't exist for hooks
• Setting overly permissive permissions like 777
• Forgetting to make the script executable

3. Given this pre-push hook script snippet, what will happen if the tests fail?

#!/bin/sh
npm test || exit 1

medium

A. The push will continue regardless of test results

B. The script will delete the remote branch

C. The tests will be skipped

D. The push will be blocked and stopped

Solution

1. Step 1: Understand the script logic

   The script runs npm test. If tests fail, npm test returns non-zero, triggering exit 1.

2. Step 2: Effect of exit 1 in pre-push hook

   Exiting with a non-zero code stops the push process, blocking the push.

3. Final Answer:

   The push will be blocked and stopped -> Option D

4. Quick Check:

   Exit 1 in pre-push = block push [OK]

Hint: Exit non-zero in pre-push stops the push [OK]

Common Mistakes:

• Assuming push continues even if tests fail
• Thinking tests are skipped automatically
• Confusing exit codes with success

4. You wrote a pre-push hook script but it does not run when you push. What is the most likely cause?

medium

A. The remote repository is down

B. The script is missing execute permissions

C. You forgot to commit your changes

D. The branch name is incorrect

Solution

1. Step 1: Check script execution requirements

   Git requires hook scripts to have execute permission to run them.

2. Step 2: Identify common cause of hook not running

   If the script lacks execute permission, Git silently skips running it.

3. Final Answer:

   The script is missing execute permissions -> Option B

4. Quick Check:

   Missing execute permission = hook won't run [OK]

Hint: Check execute permission if hook doesn't run [OK]

Common Mistakes:

• Blaming remote repository for local hook issues
• Thinking commit status affects hook execution
• Assuming branch name affects hook running

5. You want your pre-push hook to run tests only on files changed in the last commit before pushing. Which approach is best?

hard

A. Use git diff --name-only HEAD~1 HEAD inside the hook to get changed files and run tests accordingly

B. Run tests on all files every time without checking changes

C. Manually list files in the hook script each time

D. Push first, then run tests on the remote repository

Solution

1. Step 1: Identify how to detect changed files

   The command git diff --name-only HEAD~1 HEAD lists files changed in the last commit.

2. Step 2: Use this command in pre-push hook

   Using this inside the hook lets you run tests only on changed files, saving time and resources.

3. Final Answer:

   Use git diff --name-only HEAD~1 HEAD inside the hook to get changed files and run tests accordingly -> Option A

4. Quick Check:

   Detect changed files with git diff for selective tests [OK]

Hint: Use git diff to find changed files for selective tests [OK]

Common Mistakes:

• Running tests on all files unnecessarily
• Manually updating file lists each time
• Running tests after push instead of before