I have a git repo with 2 directories and multiple branches, I want to split them and create all branches
`-- Big-repo |-- dir1 `-- dir2 Branches : branch1, branch2, branch3 ...
What I want
I want to split dir1 and dirt as two separate repos and retain branches branch1, branch2 … in both repositories.
dir1 Branches : branch1, branch2, branch3 ... dir2 Branches : branch1, branch2, branch3 ...
What I tried:
I am able to split them into 2 repos using
git subtree split -P dir1 -b dir1-only git subtree split -P dir2 -b dir2-only
But, it is not creating any branches after separation.
To get all branches:
git checkout branch1 (in Big-repo) git subtree split -p dir1 -b dir1-branch1 git checkout branch2 (in Big-repo) git subtree split -p dir1 -b dir1-branch2 And push these branches to newly created repo.
This involves more manual effort and I am sure there might be a quick way to achieve this?
git filter-branch offers exactly the functionality you want. With the
--subdirectory-filter option you can create a new set of commits where the contents of
subDirectory are at the root of the directory.
git filter-branch --prune-empty --subdirectory-filter subDirectory -- --branches
The following is an example to perform this in a safe way. You need to perform this for each subdirectory that will be isolated into its own repo, in this case
First clone your repository to keep the changes isolated:
git clone yourRemote dir1Clone cd dir1Clone
To prepare the cloned repository we will recreate all remote branches as local ones. We skip the one starting with
* since that is the current branch, which in this case would read
(no branch) since we are in a headless state:
# move to a headless state # in order to delete all branches without issues git checkout --detach # delete all branches git branch | grep --invert-match "*" | xargs git branch -D
To recreate all remote branches locally we go through the results of
git branch --remotes. We skip the ones containing
-> since those are not branches:
# get all local branches for remote git branch --remotes --no-color | grep --invert-match "\->" | while read remote; do git checkout --track "$remote" done # remove remote and remote branches git remote remove origin
Finally run the
filter-branch command. This will create new commits with all the commits that touch the
dir1 subdirectory. All branches that also touch this subdirectory will get updated. The output will list all the references that where not updated, which is the case for branches that do not touch
dir1 at all.
# Isolate dir1 and recreate branches # --prune-empty removes all commits that do not modify dir1 # -- --all updates all existing references, which is all existing branches git filter-branch --prune-empty --subdirectory-filter dir1 -- --all
After this you will have a new set of commits that have
dir1 at the root of the repository. Just add your remote to push the new commits, or use these as a new repository altogether.
As an additional last step if you care about the repository size:
Even if all branches where updated your repository will still have all the objects of the original repository, tho only reachable through the ref-logs. If you want to drop these read how to garbage collect commits
Some additional resources:
This script does the job for me:
#!/bin/bash set -e if [ -z "$3" ]; then echo "usage: $0 /full/path/to/repository path/to/splitfolder/from/repository/root new_origin" exit fi repoDir=$1 folder=$2 newOrigin=$3 cd $repoDir git checkout --detach git branch | grep --invert-match "*" | xargs git branch -D for remote in `git branch --remotes | grep --invert-match "\->"` do git checkout --track $remote git add -vA * git commit -vam "Changes from $remote" || true done git remote remove origin git filter-branch --prune-empty --subdirectory-filter $folder -- --all #prune old objects rm -rf .git/refs/original/* git reflog expire --all --expire-unreachable=0 git repack -A -d git prune #upload to new remote git remote add origin $newOrigin git push origin master for branch in `git branch | grep -v '\*'` do git push origin $branch done