Bundler uses Semantic Versioning.

Note: In the documentation listed below, the *current* minor version number is 1.11 and the *next* minor version number is 1.12

Regardless of the version, all releases must update the and lib/bundler/version.rb files. The changelog for the first stable minor release (1.12.0) is a sum of all the preceding pre-release versions (1.12.pre.1, 1.12.pre.2, etc) for that minor version. The changelog for the first stable minor release is left blank unless there are fixes included since the last pre/rc release.


In general, master will accept PRs for:

  • feature merges for the next minor version (1.12)
  • regression fix merges for a patch release on the current minor version (1.11)
  • feature-flagged development for the next major version (2.0)

Breaking releases

Bundler cares a lot about preserving compatibility. As a result, changes that break backwards compatibility should (whenever this is possible) include a feature release that is backwards compatible, and issue warnings for all options and behaviors that will change.

We try very hard to only release breaking changes when incrementing the major version of Bundler.

Cherry picking

Patch releases are made by cherry-picking bug fixes from master.

When we cherry-pick, we cherry-pick the merge commits using the following command:

bash $ git cherry-pick -m 1 MERGE_COMMIT_SHAS

For example, for PR #5029, we cherry picked commit dd6aef9, not 4fe9291 using:

bash $ git cherry-pick -m 1 dd6aef9

The rake release:prepare_patch command will automatically handle cherry-picking, and is further detailed below.


Bundler maintains a list of changes present in each version in the file. Entries should not be added in pull requests, but are rather written by the Bundler maintainers before the release.

To fill in the changelog, maintainers can go through the relevant PRs using the rake release:open_unreleased_prs and manually add a changelog entry for each PR that it’s about to be released.

If you’re releasing a patch level version, you can use rake release:open_unreleased_prs to instead label each relevant PR with the proper milestone of the version to be release. Then the rake release:patch task will go only through those PRs, and prompt you to add a changelog entry for each of them.


Minor releases

While pushing a gem version to is as simple as rake release, releasing a new version of Bundler includes a lot of communication: team consensus, git branching, changelog writing, documentation site updates, and a blog post.

Dizzy yet? Us too.

Here’s the checklist for releasing new minor versions:

  • [ ] Check with the core team to ensure that there is consensus around shipping a feature release. As a general rule, this should always be okay, since features should never break backwards compatibility
  • [ ] Create a new stable branch from master (see Branching below)
  • [ ] Update version.rb to a prerelease number, e.g. 1.12.pre.1
  • [ ] Update to include all of the features, bugfixes, etc for that version.
  • [ ] Run rake release, tweet, blog, let people know about the prerelease!
  • [ ] Wait a minimum of 7 days
  • [ ] If significant problems are found, increment the prerelease (i.e. 1.12.pre.2) and repeat, but treating .pre.2 as a patch release. In general, once a stable branch has been cut from master, it should not have master merged back into it.

Wait! You’re not done yet! After your prelease looks good:

  • [ ] Update version.rb to a final version (i.e. 1.12.0)
  • [ ] In the rubygems/bundler-site repo, copy the previous version’s docs to create a new version (e.g. cp -r v1.11 v1.12)
  • [ ] Update the new docs as needed, paying special attention to the “What’s new” page for this version
  • [ ] Write a blog post announcing the new version, highlighting new features and notable bugfixes
  • [ ] Run rake release in the bundler repo, tweet, link to the blog post, etc.

At this point, you’re a release manager! Pour yourself several tasty drinks and think about taking a vacation in the tropics.

Beware, the first couple of days after the first non-prerelease version in a minor version series can often yield a lot of bug reports. This is normal, and doesn’t mean you’ve done anything wrong as the release manager.


Minor releases of the next version start with a new release branch from the current state of master: 1-12-stable, and are immediately followed by a .pre.1 release.

Once that -stable branch has been cut from master, changes for that minor release series (1.12) will only be made intentionally, via patch releases. That is to say, changes to master by default won’t make their way into any 1.12 version, and development on master will be targeting the next minor or major release.

Patch releases (bug fixes!)

Releasing new bugfix versions is really straightforward. Increment the tiny version number in lib/bundler/version.rb, and in add one bullet point per bug fixed. Then run rake release from the -stable branch, and pour yourself a tasty drink!

PRs containing regression fixes for a patch release of the current minor version are merged to master. These commits need to be cherry-picked from master onto the minor branch (1-12-stable).

There is a rake release:prepare_patch rake task that helps with creating a patch release. It takes a single argument, the exact patch release being made (e.g. 1.12.3), but if not given it will bump the tiny version number by one. This task checks out the appropriate stable branch (1-12-stable), grabs the 1.12.3 milestone from GitHub, ensures all PRs are closed, and then cherry-picks those changes (and only those changes) to a new branch based off the stable branch. Then bumps the version in the version file and commits that change on top of the cherry-picks.

Now you have a release branch ready to be merged into the stable branch. You’ll want to open a PR from this branch into the stable branch and provided CI is green, you can go ahead, merge the PR and run rake release from the updated stable branch.

Beta testing

Early releases require heavy testing, especially across various system setups. We :heart: testers, and are big fans of anyone who can run gem install bundler --pre and try out upcoming releases in their development and staging environments.

There may not always be prereleases or beta versions of Bundler. The Bundler team will tweet from the @bundlerio account when a prerelease or beta version becomes available. You are also always welcome to try checking out master and building a gem yourself if you want to try out the latest changes.

Edit this document on GitHub if you caught an error or noticed something was missing.