Re: Question: is there a short way to merge the last commit to the second last one?

From: brian m. carlson <sandals@crustytoothpaste.net>
Date: Jun 8, 2025, 21:43 UTC
Message-ID: <aEYD5X940Li_H7KU@tapette.crustytoothpaste.net>
In-Reply-To: <PN3PR01MB9597D380178A875C6FFA90E0B868A@PN3PR01MB9597.INDPRD01.PROD.OUTLOOK.COM>

On 2025-06-08 at 19:35:24, Aditya Garg wrote:

Show 16 quoted lines

> 
> 
> On 9 June 2025 1:01:19 am IST, Phillip Wood <phillip.wood123@gmail.com> wrote:
> >On 08/06/2025 19:57, brian m. carlson wrote:
> >> 
> >> If your goal is to just do the fixups and squash and not anything else
> >> interactive, then you can do this:
> >> 
> >>      GIT_SEQUENCE_EDITOR=true git rebase -i --autosquash
> >
> >Just a quick note to say that since git v2.44.0 you can just run
> >
> >	git rebase --autosquash
> >
> 
> Silly question but how does it get to know what is the fixup commit?

That's actually a great question. When you do `git commit --squash REVISION`, it takes the summary of the commit specified by `REVISION` and precedes it with `squash! `, and for `--fixup`, it does `fixup! `.

Then, it's just a matter of re-ordering the squash or fixup commits in order after the commit with the corresponding summary.

So with this shell script:

---- #!/bin/sh

git init --object-format=sha256 test-repo cd test-repo

echo abc >file.txt git add file.txt git commit -m 'Initial commit'

echo def >file.txt git add file.txt git commit --fixup HEAD git show ----

You get something like this:

----
Initialized empty Git repository in /tmp/user/1000/test-repo/.git/
[dev (root-commit) 7327102] Initial commit
 1 file changed, 1 insertion(+)
 create mode 100644 file.txt
[dev 8bdd271] fixup! Initial commit
 1 file changed, 1 insertion(+), 1 deletion(-)
commit 8bdd271b6d4e22b7ca697c2d4499fd3e0825977d7d2c917b92e1f1f12383f52c
Author: brian m. carlson <sandals@crustytoothpaste.net>
Date:   Sun Jun 8 21:41:43 2025 +0000

    fixup! Initial commit

diff --git a/file.txt b/file.txt
index e0ef420..559afde 100644
--- a/file.txt
+++ b/file.txt
@@ -1 +1 @@
-abc
+def
----

Of course, `--autosquash` does require using `--fixup` and `--squash` or
otherwise naming the commits that way.

-- 
brian m. carlson (they/them)
Toronto, Ontario, CA