Conventional Commit Messages

See how a minor change to your commit message style can make a difference.

git commit -m"<type>(<optional scope>): <description>" \
  -m"<optional body>" \
  -m"<optional footer>"

Note

This cheatsheet is opinionated, however it does not violate the specification of conventional commits

Tip

Take a look at git-conventional-commits ; a CLI util to ensure these conventions, determine version and generate changelogs.

Commit Message Formats

General Commit

<type>(<optional scope>): <description>
empty line as separator
<optional body>
empty line as separator
<optional footer>

Initial Commit

chore: init

Merge Commit

Merge branch '<branch name>'

^{Follows default git merge message}

Revert Commit

Revert "<reverted commit subject line>"

^{Follows default git revert message}

Types

• Changes relevant to the API or UI:
  • feat Commits that add, adjust or remove a new feature to the API or UI
  • fix Commits that fix an API or UI bug of a preceded feat commit
• refactor Commits that rewrite or restructure code without altering API or UI behavior
  • perf Commits are special type of refactor commits that specifically improve performance
• style Commits that address code style (e.g., white-space, formatting, missing semi-colons) and do not affect application behavior
• test Commits that add missing tests or correct existing ones
• docs Commits that exclusively affect documentation
• build Commits that affect build-related components such as build tools, dependencies, project version, CI/CD pipelines, ...
• ops Commits that affect operational components like infrastructure, deployment, backup, recovery procedures, ...
• chore Miscellaneous commits e.g. modifying .gitignore, ...

Scopes

The scope provides additional contextual information.

• The scope is an optional part
• Allowed scopes vary and are typically defined by the specific project
• Do not use issue identifiers as scopes

Breaking Changes Indicator

• A commit that introduce breaking changes must be indicated by an ! before the : in the subject line e.g. feat(api)!: remove status endpoint
• Breaking changes should be described in the commit footer section, if the commit description isn't sufficiently informative

Description

The description contains a concise description of the change.

• The description is a mandatory part
• Use the imperative, present tense: "change" not "changed" nor "changes"
  • Think of This commit will... or This commit should...
• Do not capitalize the first letter
• Do not end the description with a period (.)
• I case of breaking changes also see breaking changes indicator

Body

The body should include the motivation for the change and contrast this with previous behavior.

• The body is an optional part
• Use the imperative, present tense: "change" not "changed" nor "changes"

Footer

The footer should contain issue references and informations about Breaking Changes

• The footer is an optional part, except if the commit introduce breaking changes
• Optionally reference issue identifiers (e.g., Closes #123, Fixes JIRA-456)
• Breaking Changes must start with the word BREAKING CHANGE:
  • For a single line description just add a space after BREAKING CHANGE:
  • For a multi line description add two new lines after BREAKING CHANGE:

Versioning

• If your next release contains commit with...
  • Breaking Changes incremented the major version
  • API relevant changes (feat or fix) incremented the minor version
• Else increment the patch version

Examples

• feat: add email notifications on new direct messages
  

• feat(shopping cart): add the amazing button
  

• feat!: remove ticket list endpoint
  
  refers to JIRA-1337
  
  BREAKING CHANGE: ticket endpoints no longer supports list all entities.
  

• fix(shopping-cart): prevent order an empty shopping cart
  

• fix(api): fix wrong calculation of request body checksum
  

• fix: add missing parameter to service call
  
  The error occurred due to <reasons>.
  

• perf: decrease memory footprint for determine unique visitors by using HyperLogLog
  

• build: update dependencies
  

• build(release): bump version to 1.0.0
  

• refactor: implement fibonacci number calculation as recursion
  

• style: remove empty line
  

---

Git Hook Scripts to ensure commit message header format

Click to expand

commit-msg Hook (local)

• Create a commit-msg hook using git-conventional-commits cli

pre-receive Hook (server side)

• create following file in your repository folder .git/hooks/pre-receive

  #!/usr/bin/env bash
  
  # Pre-receive hook that will block commits with messages that do not follow regex rule
  
  commit_msg_type_regex='feat|fix|refactor|style|test|docs|build'
  commit_msg_scope_regex='.{1,20}'
  commit_msg_description_regex='.{1,100}'
  commit_msg_regex="^(${commit_msg_type_regex})(\(${commit_msg_scope_regex}\))?: (${commit_msg_description_regex})\$"
  merge_msg_regex="^Merge branch '.+'\$"
  
  zero_commit="0000000000000000000000000000000000000000"
  
  # Do not traverse over commits that are already in the repository
  excludeExisting="--not --all"
  
  error=""
  while read oldrev newrev refname; do
    # branch or tag get deleted
    if [ "$newrev" = "$zero_commit" ]; then
      continue
    fi
  
    # Check for new branch or tag
    if [ "$oldrev" = "$zero_commit" ]; then
      rev_span=`git rev-list $newrev $excludeExisting`
    else
      rev_span=`git rev-list $oldrev..$newrev $excludeExisting`
    fi
  
    for commit in $rev_span; do
      commit_msg_header=$(git show -s --format=%s $commit)
      if ! [[ "$commit_msg_header" =~ (${commit_msg_regex})|(${merge_msg_regex}) ]]; then
        echo "$commit" >&2
        echo "ERROR: Invalid commit message format" >&2
        echo "$commit_msg_header" >&2
        error="true"
      fi
    done
  done
  
  if [ -n "$error" ]; then
    exit 1
  fi

• ⚠ make .git/hooks/pre-receive executable (unix: chmod +x '.git/hooks/pre-receive')

---

References

• https://www.conventionalcommits.org/
• https://github.com/angular/angular/blob/master/CONTRIBUTING.md
• http://karma-runner.github.io/1.0/dev/git-commit-msg.html

• https://github.com/github/platform-samples/tree/master/pre-receive-hooks
• https://github.community/t5/GitHub-Enterprise-Best-Practices/Using-pre-receive-hooks-in-GitHub-Enterprise/ba-p/13863