The commit-msg hook is a script used in Git version control systems to enforce commit message formatting rules or to perform certain checks before a commit is finalized. Here's detailed information about this hook:
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Functionality: The commit-msg hook runs just after the user enters a commit message, but before the commit is actually made. It can be used to:
- Check the commit message format.
- Modify the commit message.
- Reject commits that do not meet predefined criteria.
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Location: This hook script is typically located in the
.git/hooks/ directory of a Git repository. For example, if your project is in /path/to/project, the hook would be at /path/to/project/.git/hooks/commit-msg.
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Usage:
- The script receives one argument, the path to a file containing the commit message.
- Exit status of the hook script:
0 indicates success, allowing the commit to proceed.- Non-zero exit status will abort the commit.
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History: Git hooks, including commit-msg, were introduced in Git's early versions. They were part of the original design to provide flexibility and automation around the Git workflow, allowing developers to enforce coding standards, project policies, or to integrate with other tools.
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Context:
- This hook is particularly useful in:
- Enforcing commit message conventions like those suggested by projects like Conventional Commits.
- Preventing accidental commits of sensitive information by checking the commit message for certain keywords or patterns.
- Integrating with Continuous Integration (CI) systems to ensure commits meet certain criteria before triggering builds or deployments.
For further reading and understanding: