Move Code Changes Between Branches With Git Patch Files

With patch files Git provides an easy-to-use way to move code changes between branches.

A patch file contains information about the changed lines in a comparable way like it’s shown when doing a git diff.

Here’s how to use it.

Move code from branch A to branch B

Move code from branch A to branch B, where branch B does not depend on branch A.

1. On branch A create patch file:

git format-patch -1 COMMIT_ID

2. On branch B apply the created patch file:

git apply PATCH_FILE

3. Interactively choose hunks to add:

git add -p

If branch B depends on branch A and you want to move a change to branch B, then you can do the same. But you need to remove the conflicts.

By the way: The same works for moving changes between repositories.

Closer view at format-patch

This creates a patch file for COMMIT_ID:

git format-patch -1 COMMIT_ID

For the latest commit on the current branch (= HEAD) the following works, too:

git format-patch -1 HEAD

This creates two patch files for the last two commits beginning on COMMIT_ID and including COMMIT_ID:

git format-patch -2 COMMIT_ID

This creates two patch files for the last two commits on the current branch (= HEAD):

git format-patch HEAD~2

This combines the two latest commits into one:

git format-patch -2 HEAD --stdout > last-two.patch

As before it can be used with a specific commits:

git format-patch -2 COMMIT_ID --stdout > last-two.patch

Conclusion

This post showed just a small subset of the possibilities of git patchsets. I can recommend to work with them to have a clean codebase and use it for moving code parts around.