Re: How to replace master branch of a repo with that of another totally unrelated repo?

[Ramkumar Ramachandra <artagnon@gmail.com>]

Hi,

PCMan writes:
> I want to rewrite a program totally from scratch rather than branching
> from current one.
> So I created a new repo for it and do the development there.
> Now it's finished and I want to replace the old program with it.
> Is it possible to replace the master branch of the old repo with the
> code in this new repo?
> I want to move the old code to a separate branch for backup, and
> replace the master branch with the master branch of the new repo.
> Since git rm -r * than git add all new files will lost history of new
> repo, it's not an option.
> The old repo is a public online repo used by multiple users. So just
> renaming the repo won't work since the users who pull code from the
> old repo will get troubles.
> What's the best strategy for smooth migration in this case?
> I'm not able to find the answer on Google.

In your old repository:
$ git checkout master # Switch to branch master
$ git checkout -b backup # Create a branch backup of master
$ git remote add new <new_repository_url> # "new" is the name of the remote
$ git fetch new # Fetch all the objects from the remote "new"
$ git checkout master # Get ready to rewrite master
$ git reset --hard new/master # Use `reset --hard` with extreme caution
$ git checkout backup # Your backup is safe here
$ # Done!

-- Ram