How to Cherry-Pick Changes from Separate Git Repositories with History
Git is a powerful version control system that allows developers to manage source code and collaborate on projects. One of the most useful features of Git is the ability to cherry-pick changes from one repository and apply them to another repository. This is especially useful when you need to reuse changes from one project in another project, or when you want to preserve the history of a change when merging it into another repository. In this blog, we will look at how to cherry-pick changes from separate Git repositories with history.
Before we dive into the steps to cherry-pick changes, let's first understand what cherry-picking is and why it's useful.
What is Cherry-Picking?
Cherry-picking is a Git feature that allows you to apply a specific commit from one repository to another repository. When you cherry-pick a commit, you are copying the changes made in that commit to a new repository, preserving the history of the change. This means that you can see who made the change, when the change was made, and why the change was made.
Why is Cherry-Picking Useful?
Cherry-picking is useful when you need to reuse changes from one repository in another repository. For example, you may have a feature that was developed in one repository that you want to use in another repository. By cherry-picking the commit that added the feature, you can easily reuse the changes in the new repository, preserving the history of the change.
Another use case for cherry-picking is when you want to preserve the history of a change when merging it into another repository. When you merge changes from one repository into another, the history of the change can be lost, making it difficult to see who made the change, when the change was made, and why the change was made. By cherry-picking the change, you can preserve the history of the change and make it easier to understand the change in the future.
Steps to Cherry-Pick Changes from Separate Git Repositories with History
Here are the steps to cherry-pick changes from separate Git repositories with history:
- Generate Patches from the Source Repository
The first step to cherry-picking changes is to generate patches from the source repository that contains the changes you want to cherry-pick. You can do this using the "git format-patch" command, which will generate a patch file for each commit in the source repository.
Here's an example of how to generate patches for a specific commit in the source repository:
git log --pretty=email --patch-with-stat --reverse --full-index --binary -- <file_path | folder_path> > ~/toggle.patch
The above Git command will create a patch file for a specific file or folder in a Git repository. The patch file will contain a log of changes made to the specified file or folder, including the author, date, and commit message for each change.
Here's what each option does:
git log: This is the Git command that
displays a log of changes in the repository.
--pretty=email: This option formats the
log output as an email, making it easier to read and process.
--patch-with-stat: This option includes
statistics about the changes in the log output, such as the number of lines
added and deleted.
--reverse: This option reverses the
order of the log output, so that the most recent changes are displayed first.
--full-index: This option includes the
full index in the log output, making it easier to identify the changes made in
each commit.
--binary: This option specifies that the
log output should include binary files.
--: This option is used to specify the
end of the options list and the beginning of the file or folder path.
<file_path | folder_path>: This is
the path to the file or folder for which you want to create a patch file.
> ~/toggle.patch: This redirects the
log output to a file named "toggle.patch" in your home directory.
$ git format-patch -k --stdout <commit-hash> > patch-file.patch
In this example, "commit-hash" is the hash of the commit you want to cherry-pick, and "patch-file.patch" is the name of the patch file that will be generated. The "--stdout" option is used to output the patches to standard output.
- Apply the Patches in the Target Repository
Next, switch to the target repository where you want to apply the changes, and use the "git am" command to apply the patches.
Here's an example of how to apply the patches in the target repository:
$ git am --directory=<directory> < patch-file.patch
In this example, "directory" is the path in the target repository where the changes should be applied, and "patch-file.patch" is the name of the patch file generated in the previous step.
That's it! You've successfully cherry-picked