Professional Git

Chapter 14Working with Trees and Modules in Git

WHAT’S IN THIS CHAPTER?

• Working with changes in multiple branches simultaneously using worktrees
• Including repositories as subprojects with submodules
• Coordinating changes in submodules with the containing project
• Addressing potential problems when using submodules
• Incorporating projects as subdirectories with subtrees

In this book, you’ve primarily been working with single projects managed in a single repository where you worked on only one branch at a time. This works well for most projects, but there are times when you need to extend this model. Two such examples include working on multiple branches concurrently in a project, and including other repositories as subprojects or subdirectories.

WORKTREES

As I discuss in Chapter 8, one nice feature of Git is that you can use the same working directory for all of the branches you need to work with. However, as it turns out, this can also be a liability.

In the past, if you were making changes in one branch and needed to switch to a new branch, you had three choices: commit your changes to get to a clean working directory, stash your changes that were in progress, or create a separate clone of the repository in a different area and work on the other branch there.

Starting with version 2.5, Git formally introduced a more workable alternative: worktrees (working trees). The idea with worktrees is that you can have multiple, separate working directories, all connected to the ...