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gitgit-rebase

How to get latest from git repository and apply my changes reordered on branch

Some background:

  1. I forked from a upstream repository.
  2. Checkout develop branch from this fork a couple of weeks ago
  3. Performed some changes and checked in (Did not push yet)
  4. Meanwhile some other changes were pushed to develop branch of upstream.

Current situation.

Priority got changed and I had worked on another feature on same develop branch. I should have created a different branch but I continued to add that new feature of top of my current changes and checked in. This means my develop branch has all my 2 weeks changes + this one new feature.

What do I want to do ?

  1. I want to get the exact copy of upstream/develop onto my current (I do not want to create another branch) develop branch and apply only my latest change to it and push it.

  2. Apply my old two weeks work on top of this change on same branch. This I'll be pushing couple of days later.

Can somebody help me with git commands and explain what's happening at back ground ?

Things I tried. git reset --hard This tell me my head is detached.

git rebase -i upstream/branch. I think this is going to apply all my changes but I only want last change I did.

Solution

  • I imagine the commit graph corresponding to your situation to look like this:

            A--B--C--X [develop]
       /
o--o--o  <-- develop from couple of weeks ago
       \
        O--O [upstream/develop]

    A--B--C is your two weeks work and X is your latest new feature.

    Now you do the following:

    1. Mark end of two weeks work

    $ git branch twoweeks C

    You need to figure out the hash of commit C and use it in the command, or alternatively, use a graphical repository browser to create the branch on that commit.

    The branch is only temporary and will be removed again at the end, but we need it now to retain the two weeks work after the next step is done.

    Result:

                    X [develop]
               /
        A--B--C [twoweeks]
       /
o--o--o--O--O [upstream/develop]

    2. Move new feature over

    $ git rebase --onto upstream/develop twoweeks develop

    Result:

            A--B--C [twoweeks]
       /
o--o--o--O--O [upstream/develop]
             \
              X [develop]

    3. Move two weeks work over

    $ git rebase develop twoweeks

    Result:

    o--o--o--O--O [upstream/develop]
             \
              X [develop]
               \
                A--B--C [twoweeks]

    4. Clean up

    1. Push the new feature

      $ git checkout develop
$ git push

      Result:

      o--o--o--O--O--X [upstream/develop] [develop]
                \
                 A--B--C [twoweeks]

    2. Fast-forward local develop branch and remove temporary branch

      $ git checkout develop
$ git merge --ff-only twoweeks

      (using --ff-only as sanity check, if it fails you did something wrong)

      $ git branch -d twoweeks

      Result:

      o--o--o--O--O--X [upstream/develop]
                \
                 A--B--C [develop]

    References