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Git Commit Message Conventions

Commit Message Conventions

These rules are adopted from the AngularJS commit conventions.

Goals

  • allow generating CHANGELOG.md by script
  • allow ignoring commits by git bisect (not important commits like formatting)
  • provide better information when browsing the history

Generating CHANGELOG.md

We use these three sections in changelog: new features, bug fixes, breaking changes. This list could be generated by script when doing a release. Along with links to related commits. Of course you can edit this change log before actual release, but it could generate the skeleton.

List of all subjects (first lines in commit message) since last release:

git log <last tag> HEAD --pretty=format:%s

New features in this release

git log <last release> HEAD --grep feature

Recognizing unimportant commits

These are formatting changes (adding/removing spaces/empty lines, indentation), missing semi colons, comments. So when you are looking for some change, you can ignore these commits - no logic change inside this commit.

When bisecting, you can ignore these by:

git bisect skip $(git rev-list --grep irrelevant <good place> HEAD)

Provide more information when browsing the history

This would add kinda “context” information. Look at these messages (taken from last few angular’s commits):

  • Fix small typo in docs widget (tutorial instructions)
  • Fix test for scenario.Application - should remove old iframe
  • docs - various doc fixes
  • docs - stripping extra new lines
  • Replaced double line break with single when text is fetched from Google
  • Added support for properties in documentation

All of these messages try to specify where is the change. But they don’t share any convention...

Look at these messages:

  • fix comment stripping
  • fixing broken links
  • Bit of refactoring
  • Check whether links do exist and throw exception
  • Fix sitemap include (to work on case sensitive linux)

Are you able to guess what’s inside ? These messages miss place specification... So maybe something like parts of the code: docs, docs-parser, compiler, scenario-runner, …

I know, you can find this information by checking which files had been changed, but that’s slow. And when looking in git history I can see all of us tries to specify the place, only missing the convention.


Format of the commit message

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

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

Subject line

Subject line contains succinct description of the change.

Allowed <type>

  • feat (feature)
  • fix (bug fix)
  • docs (documentation)
  • style (formatting, missing semi colons, …)
  • refactor
  • test (when adding missing tests)
  • chore (maintain)

Allowed <scope>

Scope could be anything specifying place of the commit change. For example $location, $browser, $compile, $rootScope, ngHref, ngClick, ngView, etc...

<subject> text

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

Message body

  • just as in use imperative, present tense: “change” not “changed” nor “changes”
  • includes motivation for the change and contrasts with previous behavior

http://365git.tumblr.com/post/3308646748/writing-git-commit-messages http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html

Message footer

Breaking changes

All breaking changes have to be mentioned in footer with the description of the change, justification and migration notes

BREAKING CHANGE: isolate scope bindings definition has changed and
    the inject option for the directive controller injection was removed.
    
    To migrate the code follow the example below:
    
    Before:
    
    scope: {
      myAttr: 'attribute',
      myBind: 'bind',
      myExpression: 'expression',
      myEval: 'evaluate',
      myAccessor: 'accessor'
    }
    
    After:
    
    scope: {
      myAttr: '@',
      myBind: '@',
      myExpression: '&',
      // myEval - usually not useful, but in cases where the expression is assignable, you can use '='
      myAccessor: '=' // in directive's template change myAccessor() to myAccessor
    }
    
    The removed `inject` wasn't generaly useful for directives so there should be no code using it.

Referencing issues

Closed bugs should be listed on a separate line in the footer prefixed with "Closes" keyword like this:

Closes #234

or in case of multiple issues:

Closes #123, #245, #992

Examples

feat($browser): onUrlChange event (popstate/hashchange/polling)

Added new event to $browser:
- forward popstate event if available
- forward hashchange event if popstate not available
- do polling when neither popstate nor hashchange available

Breaks $browser.onHashChange, which was removed (use onUrlChange instead)
fix($compile): couple of unit tests for IE9

Older IEs serialize html uppercased, but IE9 does not...
Would be better to expect case insensitive, unfortunately jasmine does
not allow to user regexps for throw expectations.

Closes #392
Breaks foo.bar api, foo.baz should be used instead
feat(directive): ng:disabled, ng:checked, ng:multiple, ng:readonly, ng:selected

New directives for proper binding these attributes in older browsers (IE).
Added coresponding description, live examples and e2e tests.

Closes #351
style($location): add couple of missing semi colons
docs(guide): updated fixed docs from Google Docs

Couple of typos fixed:
- indentation
- batchLogbatchLog -> batchLog
- start periodic checking
- missing brace
feat($compile): simplify isolate scope bindings

Changed the isolate scope binding options to:
  - @attr - attribute binding (including interpolation)
  - =model - by-directional model binding
  - &expr - expression execution binding

This change simplifies the terminology as well as
number of choices available to the developer. It
also supports local name aliasing from the parent.

BREAKING CHANGE: isolate scope bindings definition has changed and
the inject option for the directive controller injection was removed.

To migrate the code follow the example below:

Before:

scope: {
  myAttr: 'attribute',
  myBind: 'bind',
  myExpression: 'expression',
  myEval: 'evaluate',
  myAccessor: 'accessor'
}

After:

scope: {
  myAttr: '@',
  myBind: '@',
  myExpression: '&',
  // myEval - usually not useful, but in cases where the expression is assignable, you can use '='
  myAccessor: '=' // in directive's template change myAccessor() to myAccessor
}

The removed `inject` wasn't generaly useful for directives so there should be no code using it.
@samal-rasmussen
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A couple of the examples don't follow the "imperative, present tense" rule propertly. E.g. saying added instead of add and updated instead of update.

@pensebien
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Also saying change instead of change.
And can you correct this line "not allow to user regexps for throw expectations." to something that could be understood.

@cdaringe
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cdaringe commented Jan 24, 2018

Allowed <scope>
Scope could be anything specifying place of the commit change. For example $location, $browser, $compile, $rootScope, ngHref, ngClick, ngView, etc...

a change is frequently not scoped to just a "location." who do we ping to wordsmith the scope section?

i'd propose something like, "file location or a descriptor of the specific functionality changed"

@liuderchi
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@stephenparish It looks like Allowed <type> has been extended from 7 to 9 by angular team

+build
+ci
-chore
docs
feat
fix
+perf
refactor
style
test

@kasperhj
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The example docs(guide): updated fixed docs from Google Docs violates the rule of present tense in <subject>.

@kambleaa007
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must be like docs(guide): update fix docs from Google Docs

@smallhadroncollider
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Made a tool for writing consistent commit messages:
https://github.com/smallhadroncollider/cmt

I’ve used this one as an example as I wasn’t aware of any others.

@mochadwi
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mochadwi commented Jun 2, 2019

Made a tool for writing consistent commit messages:
https://github.com/smallhadroncollider/cmt

I’ve used this one as an example as I wasn’t aware of any others.

Great and awesome, with this our developer wouldn't ever try to break the rules again, now their life will be much easier.

@mochadwi
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mochadwi commented Jun 2, 2019

If you an Android Engineer or for those love using JetBrain products, here's the plugin to use this git commit convention: https://plugins.jetbrains.com/plugin/9861-git-commit-template

@emac
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emac commented Apr 19, 2020

Implemented a command line tool to wrap git command to enforce a custom git commit message convention based on "AngularJS Git Commit Message Conventions". Feel free to fork and distribute.

https://github.com/emac/gitx

@wise-introvert
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Can someone please help me with <type>s for the following scenarios:

  • Installing a new dependency
  • Restructuring folder structure
  • Updating/Changing stylesheets
  • Changing the name of an existing component

Thanks!!

@examosa
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examosa commented Jan 25, 2021

Something like the following (scopes excluded):

  • build: Install new dependency
  • refactor: Reorganize folder layout
  • style: Update style sheets
  • refactor: Rename component

@tqwewe
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tqwewe commented Jan 25, 2022

What would be the recommended <type> for commits which only remove unused packages?

@d4rkne55
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d4rkne55 commented Feb 3, 2022

@tqwewe Not really the person to recommend something, as I'm not following those conventions myself (at least not yet?), but I would say it fits "refactor" pretty well - removing dead code or unused packages is a part of refactoring, isn't it?

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