Keep a CHANGELOG

Don’t let your friends dump git logs into CHANGELOGs™

What’s a CHANGELOG?

A CHANGELOG is a file which contains a curated, chronologically ordered list of notable changes for each version of an open source project.

Changelog Example

What’s the point of a CHANGELOG?

To make it easier for users and contributors to see precisely what notable changes have been made between each release (or version) of the project.

Why should I care?

Because software tools are for people. If you don’t care, why are you contributing to open source? Surely, there must be a kernel (ha!) of care somewhere in that lovely little brain of yours.

I talked with Adam Stacoviak and Jerod Santo on The Changelog (fitting, right?) podcast about why open source maintainers and contributors should care, and the motivations behind this project. If you can spare the time (1:06), it’s a good listen.

What makes up a good CHANGELOG?

I’m glad you asked.

It’s also good to explicitly mention whether the project follows Semantic Versioning.

How can I minimize the effort required?

Always have an "Unreleased" section at the top for keeping notes on any changes.

This serves two purposes:

What makes unicorns cry?

Alright…let’s get into it.

There’s more. Help me collect those unicorn tears by opening an issue or a pull request.

Is there a standard CHANGELOG format?

Sadly, no. But I want to change that.

This project contains what I hope will become the standard CHANGELOG file for all open source projects. Take a look at it, and please suggest improvements!

What should the CHANGELOG file be named?

Well, if you can’t tell from the example above, CHANGELOG.md is the best convention so far.

Some projects also use HISTORY.txt, HISTORY.md, History.md, NEWS.txt, NEWS.md, News.txt, RELEASES.txt, RELEASE.md, releases.md, etc.

It’s a mess. All these names only makes it harder for people to find it.

Why can’t people just use a git log diff?

Because log diffs are full of noise. Can we really expect every single commit in an open source project to be meaningful and self-explanatory? That seems like a pipe dream.

Can CHANGELOG files be automatically parsed?

It’s difficult, because people follow wildly different formats and file names.

Vandamme is a Ruby gem created by the Gemnasium team and which parses many (but not all) open source project CHANGELOGs.

Why do you keep writing CHANGELOG in all caps?

You’re right, that is a bit shouty. Maybe it’s because of the de facto convention: files pertaining to an open source project should be in all caps. For instance: README, LICENSE, CONTRIBUTING.

This indicates that these files are metadata for the project. Much like open source project badges, they draw attention to themselves as information to be aware of if someone intends to use the project or contribute to it.

How can I contribute?

This document is not the truth; it’s my carefully considered opinion, along with information and examples I gathered. Although I provide an actual CHANGELOG on the GitHub repo, I have purposefully not created a proper release or clear list of rules to follow (as SemVer.org does, for instance).

This is because I want our community to reach a consensus. I believe the discussion is as important as the end result.

So please pitch in.