Conventional Commit Messages

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

Have a look at CLI util git-conventional-commits to ensure this conventions and generate changelogs

Commit Formats

Default

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

Merge

Merge branch '<branch name>'

Follows default git merge message

Types

• API relevant changes
  • feat Commits, that adds a new feature
  • fix Commits, that fixes a bug
• refactor Commits, that rewrite/restructure your code, however does not change any behaviour
  • perf Commits are special refactor commits, that improve performance
• style Commits, that do not affect the meaning (white-space, formatting, missing semi-colons, etc)
• test Commits, that add missing tests or correcting existing tests
• docs Commits, that affect documentation only
• build Commits, that affect build components like build tool, ci pipeline, dependencies, project version, ...
• ops Commits, that affect operational components like infrastructure, deployment, backup, recovery, ...
• chore Miscellaneous commits e.g. modifying .gitignore

Scopes

The scope provides additional contextual information.

• Is an optional part of the format
• Allowed Scopes depends on the specific project
• Don't use issue identifiers as scopes

Subject

The subject contains a succinct description of the change.

• Is a mandatory part of the format
• Use the imperative, present tense: "change" not "changed" nor "changes"
• Don't capitalize the first letter
• No dot (.) at the end

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

• Is an optional part of the format
• Use the imperative, present tense: "change" not "changed" nor "changes"
• This is the place to mention issue identifiers and their relations

Footer

The footer should contain any information about Breaking Changes and is also the place to reference Issues that this commit refers to.

• Is an optional part of the format
• optionally reference an issue by its id.
• Breaking Changes should start with the word BREAKING CHANGES: followed by space or two newlines. The rest of the commit message is then used for this.

Examples

• feat(shopping cart): add the amazing button
  

• feat: remove ticket list endpoint
  
  refers to JIRA-1337
  BREAKING CHANGES: ticket enpoints no longer supports list all entites.
  

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

• build(release): bump version to 1.0.0
  

• build: update dependencies
  

• refactor: implement calculation method as recursion
  

• style: remove empty line
  

Git Hook Scripts to ensure commit message header format

commit-msg Hook (local)

• create following file in your local repository folder.git-hooks/commit-msg

  #!/usr/bin/env sh
  
  commit_message="$1"
  # exit with a non zero exit code incase of an invalid commit message
  
  # use git-conventional-commits, see https://github.com/qoomon/git-conventional-commits
  git-conventional-commits commit-msg-hook "$commit_message"
  
  # or verify $commit_message with your own tooling
  # ...
  

• make .git-hooks/commit-msg executable (unix: chmod +x '.git-hooks/commit-msg')
• set git hook directory to .githooks git config core.hooksPath '.git-hooks'
• commit .git-hooks directory if you want to share them with your team, they only need to call the git config command once after cloning the repository

pre-receive Hook (server side)

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

  #!/usr/bin/env sh
  
  # Pre-receive hook that will block commits with messges 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_subject_regex='.{1,100}'
  commit_msg_regex="^(${commit_msg_type_regex})(\(${commit_msg_scope_regex}\))?: (${commit_msg_subject_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