I have a git repo with a linear local history of, let’s say, 10 commits, where the first 5 is in branch1‘s history, and the last 5 commits is in branch2‘s history, and I want to fix the descriptions/author/date/other properties of these ten commits by amending them. The situation would be like this:

---(old history)---A--B--C--D--E--F--G--H--I--J
                               ^              ^
                               |              |
                            branch1       branch2

I’m not sure about how to proceed here. I can think of two strategies to do what I want to do, but I want to understand their potential effects first.

1. instead of doing a longer interactive rebase of 10 commits, I prefer to switch to branch1 first, do an interactive rebase over its last 5 commits, and when I’m done, switch to branch2 and do an interactive rebase of its last 5 commits. But since rebasing implies the creation of new commits in a “new branch”, I don’t know what would happen with the parent of the HEAD of branch1. The question is, will that strategy create some sort of weird state like this (let’s call branch1' the new branch after the rebase):

   ---(old history)---?--?--?--?--?--F--G--H--I--J
                    |             ^              ^
                    |             |              |
                    |          branch1(???)    branch2(???)
                    |
                    |
                    --A--B--C--D--E
                                  ^
                                  |
                               branch1'
   

   or will git fix the parent of F in the right way?

2. The other strategy is switching to branch2 and do an interactive rebase of its last 10 commits directly; but, again, the question is, where will the HEAD of branch1 point to then after the rebase? To a commit that is not in the branch2 history anymore?