commit-msg hook for message validation in Git - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a commit-msg hook in Git?

A commit-msg hook is a script that runs automatically after a commit message is entered but before the commit is finalized. It checks the commit message to ensure it meets certain rules or formats.

beginner

Where do you place a commit-msg hook script in a Git repository?

You place the commit-msg hook script inside the .git/hooks/ directory of your repository, and it must be executable.

intermediate

What happens if a commit-msg hook script exits with a non-zero status?

If the commit-msg hook script exits with a non-zero status, Git stops the commit process and shows an error message. This prevents the commit from being saved.

beginner

Give an example of a simple rule a commit-msg hook might enforce.

A simple rule could be that the commit message must start with a capital letter and be at least 10 characters long.

beginner

How can you test a commit-msg hook script?

You can test it by trying to make a commit with different messages and seeing if the hook allows or blocks the commit based on your rules.

Where is the commit-msg hook script located in a Git repository?

A .git/hooks/

B .git/commit-msg/

C root directory

D any directory

The commit-msg hook script must be placed inside the .git/hooks/ directory.

What does a non-zero exit code from a commit-msg hook script do?

A Automatically fixes the commit message

B Allows the commit to proceed

C Deletes the commit message

D Stops the commit and shows an error

A non-zero exit code stops the commit process and shows an error message.

Which of these is a valid use of a commit-msg hook?

A Run unit tests

B Check commit message format

C Push to remote repository

D Merge branches

The commit-msg hook is used to check the commit message format before committing.

How do you make a commit-msg hook script executable?

A No action needed

B Rename it to <code>commit-msg.sh</code>

C Run <code>chmod +x .git/hooks/commit-msg</code>

D Place it in the root directory

You must make the script executable with chmod +x.

What file does the commit-msg hook receive as input?

A The file containing the commit message

B The staged files

C The repository config file

D The last commit hash

The hook receives the path to the file containing the commit message as its first argument.

Explain how a commit-msg hook can help maintain commit message quality.

Think about how automatic checks can stop bad messages.

Describe the steps to create and enable a commit-msg hook for message validation.

Focus on script location, permissions, and testing.