How to implement the "amend!" commit ?

Hi Everyone,

Implementing "amend!" commit would be an alternative to the fixup!/squash! commit that addresses the issue as opened here[1]. Also the related patches[2], adds the options to `fixup` command in interactive rebase and supports the "amend!" commit upon `--autosquash`. Next, after discussing with Phillip and Christian, there could be 3 possibilities to implement the "amend!" commit (UI):

Firstly, the `--fixup=<commit>` to have option like, `--fixup=reword/amend:<commit>`

So, `git commit --fixup` can have 3 options:

a) `--fixup=<commit>`, work as of now, make fixup! commit. b) `--fixup=amend:<commit>`, make "amend!" commit, takes changes and also opens the editor for a new message (Here it adds a new message to amend! commit's message body and upon autosquash it will fixup up the content and reword the original commit message i.e replaces the original commit message with the "amend!" commit's message). c) `--fixup=reword:<commit>`, makes (empty) "amend!" commit, do not take changes and open the editor for a new message(Here, upon autosquash it will just reword the original commit message).

Secondly, As an alternative to above, we can use `--fixup=<commit> --amend` and `--fixup=<commit> --reword`.

Next, To use only, `--fixup=<commit> --edit` to make the "amend!" commit.

Also as discussed earlier[3] we are avoiding the use of additional options like `git commit --amend=<commit>` inorder to avoid confusion of doing similar things in different ways. So, I wonder which could be the best way to proceed with or if any other way to implement "amend!" commit ?

Thanks and Regards, Charvi

[1] https://github.com/gitgitgadget/git/issues/259 [2] https://lore.kernel.org/git/20210108092345.2178-1-charvi077@gmail.com/ [3] https://lore.kernel.org/git/95cc6fb2-d1bc-11de-febe-c2b5c78a6850@gmail.com/