Splitting git commit into a few commits

Question

I have fixed two bugs in a piece of code, and it modifies common files. For example, bug fix 1 modified file A, B, C, and bug fix 2 modified B, C, and D. I have all changes in one commit. For the purpose of code reviews, I need to split the changes into two commits (two branches actually).

What I am thinking is that from my current branch fix, I create two branches like git branch fix-1 fix and git branch fix-2 fix. Both branches have all changes. Now, in branch fix-1, I would like to keep the changes relevant to fix 1 only, that is, all changes in file A, and parts of changes in files B and C. Is it possible to do it in git? What command is relevant for this?

I know that in git add, I can do interactive add where I can select hunks of code for adding, not just at file level. Is there something similar I can do here?

Answer 1

If the commit was your last commit, here is a solution.

1. Checkout the branch with the fix

   git checkout fix
   

2. Reset back to before the fixes, but keep the changes in your working dir

   git reset HEAD^
   

3. Create branch for fix-1

   git checkout -b fix-1
   

4. Add/commit fix-1 fixes

   git add -p
   git commit
   

5. Stash the remaining changes

   git stash
   

6. Checkout/create branch for fix-2

   git checkout -b fix-1
   

7. Pop off your stashed changes

   git stash pop
   

8. Commit/add them

   git commit -a