# Conventional Commits

## Summary

A specification for adding human and machine readable meaning to commit messages.

## Specification

The Conventional Commits specification is a lightweight convention on top of commit messages. It provides an easy set of rules for creating an explicit commit history, which makes it easier to write automated tools on top of.

### Commit Message Structure

```
<type>[optional scope]: <description>

[optional body]

[optional footer(s)]
```

### Types

The commit type must be one of the following:

- **feat**: A new feature (correlates with MINOR in semantic versioning)
- **fix**: A bug fix (correlates with PATCH in semantic versioning)
- **docs**: Documentation only changes
- **style**: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
- **refactor**: A code change that neither fixes a bug nor adds a feature
- **perf**: A code change that improves performance
- **test**: Adding missing tests or correcting existing tests
- **build**: Changes that affect the build system or external dependencies
- **ci**: Changes to CI configuration files and scripts
- **chore**: Other changes that don't modify src or test files
- **revert**: Reverts a previous commit

### Rules

1. Commits MUST be prefixed with a type, which consists of a noun, `feat`, `fix`, etc., followed by the OPTIONAL scope, OPTIONAL `!`, and REQUIRED terminal colon and space.

2. The type `feat` MUST be used when a commit adds a new feature to your application or library.

3. The type `fix` MUST be used when a commit represents a bug fix for your application.

4. A scope MAY be provided after a type. A scope MUST consist of a noun describing a section of the codebase surrounded by parenthesis, e.g., `fix(parser):`

5. A description MUST immediately follow the colon and space after the type/scope prefix. The description is a short summary of the code changes, e.g., `fix: array parsing issue when multiple spaces were contained in string`.

6. A longer commit body MAY be provided after the short description, providing additional contextual information about the code changes. The body MUST begin one blank line after the description.

7. A commit body is free-form and MAY consist of any number of newline separated paragraphs.

8. One or more footers MAY be provided one blank line after the body. Each footer MUST consist of a word token, followed by either a `:<space>` or `<space>#` separator, followed by a string value.

9. A footer's token MUST use `-` in place of whitespace characters, e.g., `Acked-by` (this helps differentiate the footer section from a multi-paragraph body). An exception is made for `BREAKING CHANGE`, which MAY also be used as a token.

10. A footer's value MAY contain spaces and newlines, and parsing MUST terminate when the next valid footer token/separator pair is observed.

11. Breaking changes MUST be indicated in the type/scope prefix of a commit, or as an entry in the footer.

12. If included as a footer, a breaking change MUST consist of the uppercase text BREAKING CHANGE, followed by a colon, space, and description, e.g., `BREAKING CHANGE: environment variables now take precedence over config files`.

13. If included in the type/scope prefix, breaking changes MUST be indicated by a `!` immediately before the `:`. If `!` is used, `BREAKING CHANGE:` MAY be omitted from the footer section, and the commit description SHALL be used to describe the breaking change.

14. Types other than `feat` and `fix` MAY be used in your commit messages, e.g., `docs: update ref docs`.

15. The units of information that make up Conventional Commits MUST NOT be treated as case sensitive by implementors, with the exception of BREAKING CHANGE which MUST be uppercase.

16. BREAKING-CHANGE MUST be synonymous with BREAKING CHANGE, when used as a token in a footer.

### Examples

#### Commit with description and breaking change footer

```
feat: allow provided config object to extend other configs

BREAKING CHANGE: `extends` key in config file is now used for extending other config files
```

#### Commit with `!` to draw attention to breaking change

```
feat!: send an email to the customer when a product is shipped
```

#### Commit with scope and `!` to draw attention to breaking change

```
feat(api)!: send an email to the customer when a product is shipped
```

#### Commit with both `!` and BREAKING CHANGE footer

```
chore!: drop support for Node 6

BREAKING CHANGE: use JavaScript features not available in Node 6.
```

#### Commit with no body

```
docs: correct spelling of CHANGELOG
```

#### Commit with scope

```
feat(lang): add Polish language
```

#### Commit with multi-paragraph body and multiple footers

```
fix: prevent racing of requests

Introduce a request id and a reference to latest request. Dismiss
incoming responses other than from latest request.

Remove timeouts which were used to mitigate the racing issue but are
obsolete now.

Reviewed-by: Z
Refs: #123
```

## Why Use Conventional Commits

- Automatically generating CHANGELOGs
- Automatically determining a semantic version bump (based on the types of commits landed)
- Communicating the nature of changes to teammates, the public, and other stakeholders
- Triggering build and publish processes
- Making it easier for people to contribute to your projects, by allowing them to explore a more structured commit history

## References

- Full specification: https://www.conventionalcommits.org/en/v1.0.0/
- License: Creative Commons - CC BY 3.0
