Git – How to move certain commits to be based on another branch in git

commitgitpatch

The situation:

master is at X
quickfix1 is at X + 2 commits

Such that:

o-o-X (master HEAD)
     \
      q1a--q1b (quickfix1 HEAD)

Then I started working on quickfix2, but by accident took quickfix1 as the source branch to copy, not the master. Now quickfix2 is at X + 2 commits + 2 relevant commits.

o-o-X (master HEAD)
     \
      q1a--q1b (quickfix1 HEAD)
              \
               q2a--q2b (quickfix2 HEAD)

Now I want to have a branch with quickfix2, but without the 2 commits that belong to quickfix1.

      q2a'--q2b' (quickfix2 HEAD)
     /
o-o-X (master HEAD)
     \ 
      q1a--q1b (quickfix1 HEAD)

I tried to create a patch from a certain revision in quickfix2, but the patch doesn't preserve the commit history. Is there a way to save my commit history, but have a branch without changes in quickfix1?

Best Answer

This is a classic case of rebase --onto:

 # let's go to current master (X, where quickfix2 should begin)
 git checkout master

 # replay every commit *after* quickfix1 up to quickfix2 HEAD.
 git rebase --onto master quickfix1 quickfix2

So you should go from

o-o-X (master HEAD)
     \ 
      q1a--q1b (quickfix1 HEAD)
              \
               q2a--q2b (quickfix2 HEAD)

to:

      q2a'--q2b' (new quickfix2 HEAD)
     /
o-o-X (master HEAD)
     \ 
      q1a--q1b (quickfix1 HEAD)

This is best done on a clean working tree.
See git config --global rebase.autostash true, especially after Git 2.10.

Related Solutions

Git – How to undo ‘git add’ before commit

You can undo git add before commit with

git reset <file>

which will remove it from the current index (the "about to be committed" list) without changing anything else.

You can use

git reset

without any file name to unstage all due changes. This can come in handy when there are too many files to be listed one by one in a reasonable amount of time.

In old versions of Git, the above commands are equivalent to git reset HEAD <file> and git reset HEAD respectively, and will fail if HEAD is undefined (because you haven't yet made any commits in your repository) or ambiguous (because you created a branch called HEAD, which is a stupid thing that you shouldn't do). This was changed in Git 1.8.2, though, so in modern versions of Git you can use the commands above even prior to making your first commit:

"git reset" (without options or parameters) used to error out when you do not have any commits in your history, but it now gives you an empty index (to match non-existent commit you are not even on).

Documentation: git reset

Git – How to undo the most recent local commits in Git

Undo a commit & redo

$ git commit -m "Something terribly misguided" # (0: Your Accident)
$ git reset HEAD~                              # (1)
[ edit files as necessary ]                    # (2)
$ git add .                                    # (3)
$ git commit -c ORIG_HEAD                      # (4)

This command is responsible for the undo. It will undo your last commit while leaving your working tree (the state of your files on disk) untouched. You'll need to add them again before you can commit them again).
Make corrections to working tree files.
git add anything that you want to include in your new commit.
Commit the changes, reusing the old commit message. reset copied the old head to .git/ORIG_HEAD; commit with -c ORIG_HEAD will open an editor, which initially contains the log message from the old commit and allows you to edit it. If you do not need to edit the message, you could use the -C option.

Alternatively, to edit the previous commit (or just its commit message), commit --amend will add changes within the current index to the previous commit.

To remove (not revert) a commit that has been pushed to the server, rewriting history with git push origin master --force is necessary.

Best Answer

Related Solutions

Git – How to undo ‘git add’ before commit

Git – How to undo the most recent local commits in Git

Undo a commit & redo

Further Reading

Related Topic