Fork subdirectory of repo as a different repo in github

Question

I'd like to create a bower package / stylesheet for League of Moveable Type's Chunk typeface amongst other similar tasks.

I'm wondering if it's possible to fork their "webfonts" directory into a "fonts" directory in a new repo. This would allow me to create a bower.json file and stylesheet.

Thanks,

Diseased

splitting-a-subfolder-out-into-a-new-repository – Lapwing

Answer 1

I don't think you can directly fork it on the web UI on github, but if you are ok cloning it and pushing things manually, you can do the following

• Clone the repo

  git clone https://github.com/theleagueof/chunk
  

• Create a branch using the git subtree command for the folder only

  git subtree split --prefix=folder_name -b new_branch
  

• Create a new github repo

• Add this new repo as a remote,

  git remote add upstream https://github.com/user/repo
  

• Push the subtree

  git push upstream new_branch
  

Timelag

Any idea how to make the original repo recognise a "fork" created this way as a legitimate fork and allow submitting PRs ? – Delouse

@Delouse hmm no, direct pull requests won't work. What you can try to do is have the original repo as a remote in this new forked repo, push to the original repo, perform a subtree merge (reverse of split) on a fresh branch, and now issue a PR from this new branch. – Timelag

To push the new_branch to the master branch of the new github repo, use git push upstream new_branch:master – Apprehension

the branched repo can be updated by rerunning the subtree split command with --onto new_branch -b new_branch (per #24577584) – Viticulture

But this is just copying files and their history into a new repository, you loose the "fork" link on github and in the UI you cannot see changes against the fork ... – Metzler

Answer 2

Github has posted an article how to do this at https://help.github.com/en/articles/splitting-a-subfolder-out-into-a-new-repository:

You can turn a folder within a Git repository into a brand new repository.

If you create a new clone of the repository, you won't lose any of your Git history or changes when you split a folder into a separate repository.

1. Open Terminal.

2. Change the current working directory to the location where you want to create your new repository.

3. Clone the repository that contains the subfolder.

   $ git clone https://github.com/USERNAME/REPOSITORY-NAME
   

4. Change the current working directory to your cloned repository.

   $ cd REPOSITORY-NAME
   

5. To filter out the subfolder from the rest of the files in the repository, run git filter-branch, supplying this information:

   • FOLDER-NAME: The folder within your project that you'd like to create a separate repository from.

   • BRANCH-NAME: The default branch for your current project, for example, master or gh-pages.

   $ git filter-branch --prune-empty --subdirectory-filter FOLDER-NAME  BRANCH-NAME 
    # Filter the specified branch in your directory and remove empty commits
    > Rewrite 48dc599c80e20527ed902928085e7861e6b3cbe6 (89/89)
    > Ref 'refs/heads/BRANCH-NAME' was rewritten 
   

   The repository should now only contain the files that were in your subfolder.

6. Create a new repository on GitHub.

7. At the top of your new GitHub repository's Quick Setup page, click the clipboard to copy the remote repository URL.

   • Copy remote repository URL field

8. Check the existing remote name for your repository. For example, origin or upstream are two common choices.

   $ git remote -v
    > origin  https://github.com/USERNAME/REPOSITORY-NAME.git (fetch) 
    > origin  https://github.com/USERNAME/REPOSITORY-NAME.git (push)
   

9. Set up a new remote URL for your new repository using the existing remote name and the remote repository URL you copied in step 7.

   git remote set-url origin
   https://github.com/USERNAME/NEW-REPOSITORY-NAME.git
   

10. Verify that the remote URL has changed with your new repository name.

    $ git remote -v
     # Verify new remote URL
     > origin  https://github.com/USERNAME/NEW-REPOSITORY-NAME.git (fetch)
     > origin  https://github.com/USERNAME/NEW-REPOSITORY-NAME.git (push)
    

11. Push your changes to the new repository on GitHub.

    git push -u origin BRANCH-NAME
    

Rottenstone

On large repositories, this answer seems to perform orders of magnitude faster – Viticulture

@NoraPowers compared to what? – Cotidal

The new repo I created had a README, that prevented me to push, because I needed to pull, but that errored out with fatal: refusing to merge unrelated histories – Cotidal

Plus after I performed the git filter-branch --prune-empty the repo did not contain the subfolder only. Still all the other folders were there. So this step-by-step seems to be crappy for me. – Cotidal

I repeated the steps from a clean slate. I purged the previous new repository, recreated it. This time the filter-branch --prune-empty worked. I have no idea why it didn't work before (maybe the other repo was clean but it had extra files (excluded by gitignore BTW) when I tested stuff with an IDE. So now I had the subfolder only, and I could push into the virgin (no README, no gitignore, no LICENSE) repository. – Cotidal

After doing all this the GitHub UI does not recognize that this is an actual fork. – Cotidal