Braid is a simple tool to help track vendor branches in a Git repository.
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
.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 in the root of your repository that contains
references to external libraries or mirrors. There are two types of mirrors in
Braid: squashed and full. Mirrors are squashed by default, which is what you'll
generally want because they're faster and don't pollute your history with
commits from the mirrors.
Full mirrors are useful when you want to view imported history in your own project. You usually want this if the mirror is also a repository you have access to, for example, when using shared code across projects.
Please note that you cannot change between mirror types after the initial add. You'll have to remove the mirror and add it again.
gem install braid
Examples and usage
Let's assume you're working on a project that needs
Now let's vendor Grit:
$ braid add https://github.com/mojombo/grit.git lib/grit
Done. Feel free to inspect the changes with
git log or
If, further down the line, you want to bring new changes from Grit into your parent repository:
$ braid update lib/grit
If you make changes to the vendored library and want to generate a patch file that you can submit back to the project:
$ braid diff lib/grit > grit.patch
Use the built-in help system to find out about all commands and options:
$ braid help $ braid help add
Updating mirrors with conflicts
braid update creates a conflict, Braid will stop execution and leave the
partially committed files in your working copy, just like a normal
You'll have to resolve all conflicts and manually run
git commit. The commit
message is already prepared.
If you want to cancel the update and the merge, you have to reset your working
copy and index with
git reset --hard.
We appreciate any patches, error reports and usage ideas you may have. Please submit an issue or pull request on GitHub.
- Cristi Balan
- Norbert Crombach
- Peter Donald