How to pull after a forced git push?

Question

Suppose I pull changes from a git repo. Then the author of the repo force pushes to the central repo. Now I can't pull since the history is rewritten.

How can I pull the new commits (and abandon the old ones), assuming that the author force-pushed the correct version?

I know this is bad git workflow, but sometimes you can't avoid this.

Answer 1

Throwing away your local changes

If you want to discard your work, fetch and reset. For example, if you have a remote named origin and a branch named master:

$ git fetch origin
$ git reset --hard origin/master # Destroys your work

Keeping your local changes

If you don't want to throw away your work, you will have to do a git rebase --onto. Suppose the old origin looks like this:

A ---> B ---> C
              ^
              origin/master

And you have this:

A ---> B ---> C ---> X ---> Y ---> Z
              ^                    ^
              |                    master
              origin/master

Now, the upstream changes change things:

A ---> B ---> C ---> X ---> Y ---> Z
 \                                 ^
  ---> B'---> C'                   master
              ^          
              origin/master

You would have to run git rebase --onto origin/master <C> master, where <C> is the SHA-1 of the old origin/master branch before upstream changes. This gives you this:

A ---> B ---> C ---> X ---> Y ---> Z
 \
  ---> B'---> C'---> X'---> Y'---> Z'
              ^                    ^
              |                    master
              origin/master

Notice how B, C, X, Y, and Z are now "unreachable". They will eventually be removed from your repository by Git. In the meantime (90 days), Git will keep a copy in the reflog in case it turns out you made a mistake.

Fixing mistakes

If you git reset or git rebase wrong and accidentally lose some local changes, you can find the changes in the reflog.

In the comments, a user is suggesting git reflog expire with --expire=now but DO NOT RUN THIS COMMAND because this will DESTROY your safety net. The whole purpose of having a reflog is so that Git will sometimes save your neck when you run the wrong command.

Basically, what this command will do is immediately destroy the B, C, X, Y, and Z commits in the examples above so you can't get them back. There's no real benefit to running this command, except it might save a little bit of disk space, but Git will already purge the data after 90 days so this benefit is short-lived.

Answer 2

if have NO local commits, this will recover your checkout from a force push. You will be up to date with the remote branch, and can commit your local work later.

git fetch
git stash
git reset --hard origin/master # destroys your work
git stash pop # restores your work as local changes
git mergetool # fix any conflicts

At this point you have your local changes as they were before. Your checkout is up to date with all the changes on master, or whatever branch you are working from.

Answer 3

I came across a slightly modified version of this scenario. Here's what I did:

Initial condition

A--->B--->C--->D--->E
                    |
             local-1/master

A--->B--->C--->D--->E
                    |
              origin/master

A--->B--->C--->D--->E
                    |
             local-2/master

Squash and force push

A--->B--->CDE
           |
    local-1/master

A--->B--->CDE
           |
     origin/master

A--->B--->C--->D--->E
                    |
             local-2/master

Sync changes on local-2/master

$ git reset --soft B


    A--->B---> (local uncommitted changes)
         |
  local-2/master


$ git stash save "backup"


    A--->B
         |
  local-2/master

$ git pull origin master


    A--->B--->CDE
               |
        local-2/master

Answer 4

If you have not made any changes to the local branch, you could try the following sequence of commands. Please remember this is a crude way to achieve what you are asking for.

git checkout master
git pull
git remote update origin -p
git branch -D myBranch
git checkout myBranch

git remote update origin -p is optional.

If you made a changes and you do not care about the contents of the local branch, you could try this:

git stash
git stash drop
git checkout master
git pull
git remote update origin -p
git branch -D myBranch
git checkout myBranch

Both the techniques are really long and cumbersome. But get the job done.