Simple tool to help track vendor branches in a Git repository.
Ruby

README.md

Braid

Build Status Gem

Braid is a simple tool to help track vendor branches in a Git repository.

Motivation

Vendoring allows you take the source code of an external library and ensure it's version controlled along with the main project. This is in contrast to including a reference to a packaged version of an external library that is available in a binary artifact repository such as Maven Central, RubyGems or NPM.

Vendoring is useful when you need to patch or customize the external libraries or the external library is expected to co-evolve with the main project. The developer can make changes to the main project and patch the library in a single commit.

The problem arises when the external library makes changes that you want to integrate into your local vendored version or the developer makes changes to the local version that they want integrated into the external library.

A typical "implementation" of vendoring is to simply download or checkout the source for the external library, remove the .git or .svn directories and commit it to the main source tree. However this approach makes it very difficult to update the library. When you want to update the library do you re-apply your local changes onto a new copy of the vendored library or do you re-apply the changes from the external library to local version? Both cases involve manual generation and application of patch files to source trees.

This is where Braid comes into play. Braid makes it easy to vendor in remote git repositories and use an automated mechanism for updating the external library and generating patches to upgrade the external library.

Braid creates a file .braids.json in the root of your repository that contains references to external libraries or mirrors. The configuration allows you to control aspects of the mirroring process such as;

  • whether the mirror is locked to a particular version of the external library.
  • whether the mirror is tracking a tag or a branch.
  • whether the mirror includes the entire external library or just a subdirectory.

Installation

gem install braid

Quick usage - ruby project

Let's assume we're writing the project myproject that needs grit in lib/grit. Initialize the repo (nothing braid related here):

git init myproject
cd myproject
touch README
git add README
git commit -m "initial commit"

Now let's vendor grit:

braid add git://github.com/mojombo/grit.git lib/grit

And you're done! Braid vendored grit into lib/grit. Feel free to inspect the changes with git log or git show.

If further down the line, you want to bring new changes from grit into your repository, just update the mirror:

braid update lib/grit

If you make changes to the grit library and want to generate a patch file so that you can submit the patch file to the grit project:

braid diff lib/grit > grit.patch

Alternatively you can push changes back to the source directory directly using the following command. The command will push the changes to the branch myproject_customizations that has been branched off the source branch (master in this example). Omit the --branch argument to push directly to the source branch.

braid push lib/grit --branch myproject_customizations

Once those changes have been applied to grit you probably want to update your local version of grit again.

braid update lib/grit

More usage

Use the built in help system to find out about all commands and options:

braid help
braid help add # or braid add --help

Examples

Adding a mirror

braid add git://github.com/rails/rails.git vendor/rails

Adding a subdirectory from a mirror

This is useful if you want to add a subdirectory from a mirror into your own project.

braid add --path dist https://github.com/twbs/bootstrap.git vendor/assets/bootstrap

Adding a mirror based on a branch

braid add --branch 5-0-stable https://github.com/rails/rails.git vendor/rails

Adding a mirror based on a tag

braid add --tag v1.0 https://github.com/realityforge/backpack.git vendor/tools/backpack

Adding mirror locked to a revision

braid add --revision bf1b1e0 git://github.com/rails/rails.git vendor/rails

Updating mirrors

# Update a specific mirror
braid update vendor/plugins/cache_fu
# Update all mirrors
braid update

Updating mirrors with conflicts

If a braid update creates a conflict, braid will stop execution and leave the partially committed files in your working copy, just like a normal git merge conflict would.

You will then have to resolve all conflicts and manually run git commit. The commit message is already prepared.

If you want to cancel the braid update and the merge, you'll have to reset your working copy and index with git reset --hard.

Locking and unlocking mirrors

Lock to a particular version in the mirror.

braid update --revision 6c1c16b vendor/rails

Go back to tracking a particular branch.

braid update --branch master vendor/rails

Showing local changes made to mirrors

braid diff vendor/rails

Contributing

We appreciate any patches, error reports and usage ideas you may have. Please submit an issue or pull request on GitHub.

Subversion

While preparing to release Braid v1.0 the support for subversion repositories was removed as there was no active maintainers and inadequate test coverage. If there is anyone motivated to re-add and maintain the Subversion support, please contact the authors.

Authors

  • Cristi Balan
  • Norbert Crombach
  • Peter Donald

Contributors (alphabetically)

  • Alan Harper
  • Brad Durrow
  • Christoph Sturm
  • Dennis Muhlestein
  • Ferdinand Svehla
  • Matt McCutchen
  • Michael Klishin
  • Roman Heinrich
  • Travis Tilley
  • Tyler Rick