How to modify a previous commit with Magit? I can't stage my additions!

Hi all, sorry for the newbie quetion, I thought I got this but clearly I was wrong. So basically I want to modify a previous commit in my repo (by adding some modifications I already have in my workspace). Following a suggestion from Magit's author (here [https://emacs.stackexchange.com/a/22565/29817](https://emacs.stackexchange.com/a/22565/29817)), Magit seems to have a command that should work pretty well for me: \`magit-rebase-edit-commit\`, bound by default to \`r m\`. Point is, when I do that, I see the buffer you see in the picture. If I need to add some lines to this commit, what should I do, since there's no "Unstaged files" section? https://preview.redd.it/4owtx6p9zwc91.png?width=674&format=png&auto=webp&s=149f2a30930da94d5265d08340d435dab1904d6d

Maybe the reword option under commit? (c then w)

The rebase probably autostashes. You would see unstaged changes if you made them at this point. So you could try popping your stash. Or you create a commit of your changes, rebase, move that commit below the one to extend, make it a fixup, optionally make the other one a reword.

You're right, it autostashes indeed. But the question remains: if I want to apply part of my workspace to that commit, do I then need to * stash the modification I want to add * call magit-rebase-edit-commit * pop the stash, commit and continue/finish the rebase?

It works, but I need to actually modify the file with some modifications I already have in my workspace. Thanks for pointing that out though, I'll edit my question.

You should be able to c m or commit amend while staging your changes. Another option is to interactive rebase and un-stage a commit and add/modify/delete and commit again.

**BTW**, looks like `magit-commit-instant-fixup`, buond to `c F`, is what I was looking for. However, after trying it, I think I understand why Tarsius kept the normal rebase workflow as generic as possible, and why the "edit a commit" option works this way. So I think the hypothesis I laid out in the previous answer is indeed the idiomatic one, thanks u/Walheimat for the suggestion!

That should work. I usually do what I described, create a new fixup commit and reorder with `r i` (interactive rebase).

Indeed, stage -> commit (instant fixup) was the answer I was looking for, thank! (see [this answer thread](https://www.reddit.com/r/emacs/comments/w4ff84/comment/ih22edm/?utm_source=share&utm_medium=web2x&context=3))

`c a` will add the staged changes to the changes to the most recent commit. `c F` will let you pick a commit further back to add them to.

No, the `fixup` (`c f`) and `instant fixup` is completely idiomatic and generic and what you are asking for. Editing a commit is different - it's when you want to perhaps split a commit into many commits or something, or move some of the commit to another commit. I'm puzzled what's not working for you though. I use fixups all the time - stage what you want to add to the commit, and then `c F` and select the target commit in history.

Yes, now is clearer, thank you. I just thought that "modify a commit" was referring to fixup, but since I didn't know "fixup" was the correct term, I was looking at the wrong option. 🙂 Btw, if I wanted to split a commit in half, what should I do?

I think there are a number of ways to skin the cat - I haven't typically used `r m` (rebase - modify a commit) but I may start, as I think that does the same thing as an interactive rebase `r i` and selecting `e` on a commit for `edit`, but with fewer steps. Whichever way you get there you then find yourself in a rebase with that commit at the top of the history. I'd reset to the next commit with `x` to uncommit the offending changes, then do whatever I wanted, e.g. `fixup` parts of it into other commits, or split it into two or more new commits, or whatever, and when that's all done continue the rebase with `r r`. e.g. I have commits: - A - B - C - D And I realize I put something in `B` that should have been in `D`. - I do `r m` with the cursor on `B` in history or status - I move to the next commit, `C`, in history or status, and reset to it with `x`; now I have the contents of `B` uncommitted. - I would take the offending edits, stage them, do `c f` to put them in as a fixup to `D` (I think instant fixups won't work, nesting rebases...?) - then do `c c` to re-commit the remainder of B. History in the commit message buffer via `m-p` will let me reselect the former `B` commit message - now my edit is done and I do `r r` to complete the rebase - If I made fixup commits I may have to do another quick `r i` to collapse them Hit me up if I've got this wrong - I'm explaining this mostly from memory. (Edit: and I did - I said `c m` when I meant `r m`) (for all rebasing, I find it really nice to have `--autostash` and `--autosquash` set on by default)

1 - do your changes 2 - stage them 3 - c F to commit+apply on a commit 4 - the list of commit of the branch will pop, move your cursor to the line representing the commit to edit 5 - Cc Cc to apply this edit on the commit directly

Thanks, right now I can't follow you with my PC but you're giving me a lot to further investigate. Thanks a lot, I'll let you know if I have any comment. 😄

> `magit-rebase-edit-commit`, bound by default to `r m`. Point is, when I do that, I see the buffer you see in the picture. Yes, it does a rebase and stops to let you edit that commit. Now you need to edit it. Make your changes. Stage them. Then amend the current HEAD commit with `c a`. Then `r r` to continue the rebase (completing it, barring any conflicts with the later commits).