# Commit Message Guidelines

We have very precise rules over how our git commit messages can be formatted. This leads to more readable messages that are easy to follow when looking through the project history. But also, we use the git commit messages to generate the Angular change log.

### Commit Message Format

Each commit message consists of a header, a body and a footer. The header has a special format that includes a type, a scope and a subject:

<type>(<scope>): <subject>
<BLANK LINE>
<body>
<BLANK LINE>
<footer>


The header is mandatory and the scope of the header is optional.

Any line of the commit message cannot be longer than 100 characters! This allows the message to be easier to read on GitHub as well as in various git tools.

The footer should contain a closing reference to an issue if any.

Samples: (even more samples)

docs(changelog): update changelog to beta.5

fix(release): need to depend on latest rxjs and zone.js

The version in our package.json gets copied to the one we publish, and users need the latest of these.


### Revert

If the commit reverts a previous commit, it should begin with revert:, followed by the header of the reverted commit. In the body it should say: This reverts commit <hash>., where the hash is the SHA of the commit being reverted.

### Type

Must be one of the following:

• build: Changes that affect the build system or external dependencies (example scopes: gulp, broccoli, npm) // 依赖改变需要重新编译构建
• ci: Changes to our CI configuration files and scripts (example scopes: Circle, BrowserStack, SauceLabs) // 自动化部署配置修改
• docs: Documentation only changes // 文档修改
• feat: A new feature // 新功能
• fix: A bug fix // 修复 bug
• perf: A code change that improves performance // 性能优化
• refactor: A code change that neither fixes a bug nor adds a feature // 重构，没修复 bug 也没加新功能
• style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc) // 格式化化代码
• test: Adding missing tests or correcting existing tests // 测试代码

### Scope

The scope should be the name of the npm package affected (as perceived by the person reading the changelog generated from commit messages).

The following is the list of supported scopes:

• animations
• bazel
• benchpress
• common
• compiler
• compiler-cli
• core
• elements
• forms
• http
• language-service
• localize
• platform-browser
• platform-browser-dynamic
• platform-server
• platform-webworker
• platform-webworker-dynamic
• router
• service-worker
• zone.js

There are currently a few exceptions to the "use package name" rule:

• packaging: used for changes that change the npm package layout in all of our packages, e.g. public path changes, package.json changes done to all packages, d.ts file/format changes, changes to bundles, etc.
• changelog: used for updating the release notes in CHANGELOG.md
• docs-infra: used for docs-app (angular.io) related changes within the /aio directory of the repo
• dev-infra: used for dev-infra related changes within the directories /scripts, /tools and /dev-infra
• ngcc: used for changes to the Angular Compatibility Compiler
• ve: used for changes specific to ViewEngine (legacy compiler/renderer).
• none/empty string: useful for style, test and refactor changes that are done across all packages (e.g. style: add missing semicolons) and for docs changes that are not related to a specific package (e.g. docs: fix typo in tutorial).

### Subject

The subject contains a succinct description of the change:

• use the imperative, present tense: "change" not "changed" nor "changes"
• don't capitalize the first letter
• no dot (.) at the end

### Body

Just as in the subject, use the imperative, present tense: "change" not "changed" nor "changes". The body should include the motivation for the change and contrast this with previous behavior.

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

Breaking Changes should start with the word BREAKING CHANGE: with a space or two newlines. The rest of the commit message is then used for this.

A detailed explanation can be found in this [document][commit-message-format].