Git: Same feature on multiple branches, but not on master

Question

Our supplier has provided the code to run the linux kernel on their hardware, however there are 2 kernel versions - one that they use for Android (kernel 2.6), another for Yocto (kernel 3.01). Now I've done some modifications to the hardware and added a few drivers to support the new hardware in kernel 2.6, as shown with X and Y, but I want to apply the same change to 3.01.

Now:

   E -- F -- G -- X -- Y (2.6)
 /
A -- B -- C -- D (master)
      \
       H -- I -- J (3.01)

After:

   E -- F -- G -- X -- Y (2.6)
 /
A -- B -- C -- D (master)
      \
       H -- I -- J -- X -- Y (3.01)

What would be the best way to go about it? I've read about cherry picking and that it isn't a good practice. I would like to avoid touching the master at all since my hardware is completely irrelevant to the mainline kernel development.

Any suggestions? Thanks!

Answer 1

Your commit diagram is impossible. You cannot have two different X and Y commits with different ancestors. Git cannot do that, there is no solution that can produce that commit graph.

The answer is (good practice or not) cherry picking, and a commit graph that looks like this:

   E -- F -- G -- X -- Y (2.6)
 /
A -- B -- C -- D (master)
     \
      H -- I -- J -- X' -- Y' (3.01)

Where X' and Y' are the cherry-picked versions of X and a Y .

Whatever made you think it isn't a "good practice" is irrelevant; it's the only way to arrive at the results you're after.