How to undo "git commit --amend" done instead of "git commit"

None of these answers with the use of HEAD@{1} worked out for me, so here's my solution:

git reflog

d0c9f22 HEAD@{0}: commit (amend): [Feature] - ABC Commit Description 
c296452 HEAD@{1}: commit: [Feature] - ABC Commit Description 

git reset --soft c296452

Your staging environment will now contain all of the changes that you accidentally merged with the c296452 commit.

Use the ref-log:

git branch fixing-things HEAD@{1}
git reset --soft fixing-things

You should then have all your previously amended changes in your working copy and can commit them to a new commit.

To see a full list of previous head commits type git reflog.

You might find my other answer helpful if you are looking for a single command to achieve this and are not afraid of low-level plumbing commands.

Find your amended commits by:

git log --reflog

^{Note: You may add --patch to see the body of the commits for clarity. Same as git reflog.}

then reset your HEAD to any previous commit at the point it was fine by:

git reset SHA1 --hard

^{Note: Replace SHA1 with your real commit hash. Also note that this command will lose any uncommitted changes, so you may stash them before. Alternatively, use --soft instead to retain the latest changes and then commit them.}

Then cherry-pick the other commit that you need on top of it:

git cherry-pick SHA1

If you have pushed the commit to remote and then erroneously amended changes to that commit this will fix your problem. Issue a git log to find the SHA before the commit. (this assumes remote is named origin). Now issue these command using that SHA.

git reset --soft <SHA BEFORE THE AMMEND>
#you now see all the changes in the commit and the amend undone

#save ALL the changes to the stash
git stash

git pull origin <your-branch> --ff-only
#if you issue git log you can see that you have the commit you didn't want to amend

git stash pop
#git status reveals only the changes you incorrectly amended

#now you can create your new unamended commit

Possibly worth noting that if you're still in your editor with the commit message, you can delete the commit message and it will abort the git commit --amend command.

You can always split a commit, From the manual

• Start an interactive rebase with git rebase -i commit^, where commit is the commit you want to split. In fact, any commit range will do, as long as it contains that commit.
• Mark the commit you want to split with the action "edit".
• When it comes to editing that commit, execute git reset HEAD^. The effect is that the HEAD is rewound by one, and the index follows suit. However, the working tree stays the same.
• Now add the changes to the index that you want to have in the first commit. You can use git add (possibly interactively) or git-gui (or both) to do that.
• Commit the now-current index with whatever commit message is appropriate now.
• Repeat the last two steps until your working tree is clean.
• Continue the rebase with git rebase --continue.

Maybe can use git reflog to get two commit before amend and after amend.

Then use git diff before_commit_id after_commit_id > d.diff to get diff between before amend and after amend.

Next use git checkout before_commit_id to back to before commit

And last use git apply d.diff to apply the real change you did.

That solves my problem.

You can do below to undo your git commit —amend

1. git reset --soft HEAD^
2. git checkout files_from_old_commit_on_branch
3. git pull origin your_branch_name

====================================

Now your changes are as per previous. So you are done with the undo for git commit —amend

Now you can do git push origin <your_branch_name>, to push to the branch.

Almost 9 years late to this but didn't see this variation mentioned accomplishing the same thing (it's kind of a combination of a few of these, similar to to top answer (https://stackoverflow.com/a/1459264/4642530).

Search all detached heads on branch

git reflog show origin/BRANCH_NAME --date=relative

Then find the SHA1 hash

Reset to old SHA1

git reset --hard SHA1

Then push it back up.

git push origin BRANCH_NAME

Done.

This will revert you back to the old commit entirely.

(Including the date of the prior overwritten detached commit head)

1. Checkout to temporary branch with last commit

   git branch temp HEAD@{1}

2. Reset last commit

   git reset temp

3. Now, you'll have all files your commit as well as previous commit. Check status of all the files.

   git status

4. Reset your commit files from git stage.

   git reset myfile1.js (so on)

5. Reattach this commit

   git commit -C HEAD@{1}

6. Add and commit your files to new commit.

Simple Solution Solution Works Given: If your HEAD commit is in sync with remote commit.

• Create one more branch in your local workspace, and keep it in sync with your remote branch.
• Cherry pick the HEAD commit from the branch (where git commit --amend) was performed onto the newly created branch.

The cherry-picked commit will only contain your latest changes, not the old changes. You can now just rename this commit.

This is how you can do it easily:

• Soft reset the last commit which has old commit & amended changes

git reset --soft HEAD^

• Now commit the staged changes in a new commit

git commit -m "new commit msg"

Now push the changes and rebase this commit on top of last commit on which you had amended your changes.

This will make sure that the new commit has only amended changes.

You can use the low-level commit-tree command and the reflog to construct a new commit with your current head commit's tree, but the original (pre-amend) commit as parent. The branch is forwarded by resetting both working tree and index:

git reset --soft "$(git commit-tree HEAD^{tree} -p HEAD@{1} -m 'Commit message of new commit')"

Why does this work? Let's have a look at some ASCII drawings:

C     t:W    (HEAD@{1}) original commit with tree W
B     t:V
A     t:U

This is where we start, but after amending the commit, we are left with:

C'    t:X    (branch; HEAD) accidentally amended commit with tree X
| C   t:W    (HEAD@{1}) original commit with tree W
|/
B     t:V
A     t:U

Commit C is no longer reachable from the branch, but it still exists in Git's database and is listed in the reflog as HEAD@{1}.

What you want is to create the following new commit with the tree of the amended commit:

D     t:X    (branch; HEAD) separate commit with tree X
C     t:W    original commit with tree W
B     t:V
A     t:U

and git commit-tree HEAD^{tree} -p HEAD@{1} does exactly that: it creates commit D with tree X (same tree as of amended commit C'), but sets the parent to C (the commit before being amended). git reset is required to move the branch from the erroneous, amended commit to the correct, separate commit.