Git: Merging to a branch from another branch using Kdiff3

Question

I'm familiar with ClearCase where we can merge a file to a branch from any other branch. How is this possible in git? For eg, I have the following structure

master--->branch_2
  |
  |
  V
branch_1

So there is some independent development going in branch_1 and branch_2. I want to merge some specific code from branch_2 to branch_1 using some mergetool like kdiff3.

EDIT: Kdiff3 has an awesome merging option by comparing 2 or 3 versions of the file (from same or different branch), highlighting the conflicts. Then we can jump through each conflict, and pick the code from 1 or more versions of the file, make some edits (if necessary) and finally save the file. This feature has been quite handy for me when I worked with ClearCase. Is there a way to configure git mergetool with kdiff3 to work the same way?

Thanks in advance

Answer 1

It sounds like you want to merge a specific portion of changes from a given commit in branch_2.

If that's the case, you can use git cherry-pick --no-commit or (-n) to apply the changes from a commit in branch_2 without creating a new commit. From that point you can decide which changes to commit by staging only portions of the modified files.

Here's an example:

git checkout branch_1
git cherry-pick -n <some-commit>  # 1. Apply the changes from some commit in branch_2
                                  # without creating a new commit
git reset HEAD                    # 2. Unstage all changes from that commit
git add -p                        # 3. Decide which changes to include in the commit
git commit                        # 4. Commit those changes