Copy Git history from one repository to another

Ever need to migrate a codebase AND keep the commit history? Same. Recently I needed to migrate a codebase from one Git provider to another. I wanted to preserve the commit history since this was an npm library with versioning which meant a copy/paste over of the files would not work.

Let's walkthrough migrating a Git repository from Bitbucket to GitHub. First, let's check what our attached remotes are

╰─ git remote -v
origin    git@bitbucket.org:jongear/my-repo.git (fetch)
origin    git@bitbucket.org:jongear/my-repo.git (push)

Here you can see my origin is set to git@bitbucket.org:jongear/my-repo, Git allows you to have multiple remotes attached which will be important. I created a holding repo in GitHub that I would like to migrate to. Let's say the name is jongear/new-repo. Next, let's add the new repo as a remote in our existing local Bitbucket repository

╰─ git remote add gh-origin https://github.com/jongear/new-repo.git
╰─ git remote -v
gh-origin    https://github.com/jongear/new-repo.git (fetch)
gh-origin    https://github.com/jongear/new-repo.git (push)
origin    git@bitbucket.org:jongear/my-repo.git (fetch)
origin    git@bitbucket.org:jongear/my-repo.git (push)

Great, so now we can see our codebase has two origins attached. The original Bitbucket origin and our new GitHub one. To migrate our changes to the new GitHub repository, we need to initiate a push command

╰─ git push gh-origin master
Counting objects: 11815, done.
Compressing objects: 100% (6605/6605), done.
Writing objects: 100% (11815/11815), 7.17 MiB | 7.03 MiB/s, done.
Total 11815 (delta 4358), reused 11815 (delta 4358)
remote: Resolving deltas: 100% (4358/4358), done.
To https://github.com/jongear/new-repo.git
 * [new branch]       master -> master

You can do this for any other significant branches you have such as a develop branch. Once you have everything the way you like it.

Now it's time to unhook the old provider. git remote rm {originName} will remove an origin based off the name provided. Since we no longer care about our Bitbucket origin, we will remove it.

╰─ git remote rm origin
╰─ git remote -v
gh-origin    https://github.com/jongear/new-repo.git (fetch)
gh-origin    https://github.com/jongear/new-repo.git (push)

Now that our Bitbucket origin has been removed, let's rename our GitHub origin from gh-origin to origin

╰─ git remote rename gh-origin origin
╰─ git remote -v
origin https://github.com/jongear/new-repo.git (fetch)
origin https://github.com/jongear/new-repo.git (push)

And there we go. We successfully migrated our code to a new Git provider and changed our origin to point to our new provider. We are safe to tear down our old repository.