SVN to Git Migration: Move a selected set of commits to a new repository

Question

I am trying to migrate a very old svn repository to git and to rearrange directory structure. Initially the svn repository structure was like this.

Stage A

application/
            .svn
            dev/
                dev1/
                dev2/               
            test/
                test1/
                test2/
            others/
                others1/
                others2/

Over some years, the structure changed to something like this.

Stage B

application/
            .svn
            dev1/
                dev/
                test/
                others/
            dev2/
                dev/
                test/
                others/

Contents of

• dev/dev1 is moved to dev1/dev
• test/test1 is moved to dev1/test
• others/others1 is moved to dev1/others

Same movement is done for dev2 directory as well.

Now I have moved the source code to git using git svn clone, maintaining all commit history. Currently the directory structure is like this.

Stage C

application/
            .git
            dev1/
                dev/
                test/
                others/
            dev2/
                dev/
                test/
                others/

Now I want to split this repository into two new repositories like this

Stage D

dev1/
    .git
    dev/
    test/
    others/


dev2/
    .git/
    dev/
    test/
    others/

I have tried git filter-branch subdirectory-filter like this.

git filter-branch --subdirectory-filter dev1 --prune-empty

which successfully created the directory structure I wanted, maintaining all the commit history of dev1 upto the movement mentioned in Stage B. All the commits before the movement mentioned in Stage B is lost.

What I want to achieve is to create directory structure mentioned in Stage D, maintaining all commit histories of all files which are present in dev1 and dev2.

Important : Most of the files present in dev1 and dev2 are created even before the creation of dev1 and dev2 - those files are later moved to dev1/dev2.

Answer 1

In my opinion you should create 2 copies of the repository from stage C — dev1 and dev2. Then remove the directory dev2 from the repo dev1 and remove the directory dev1 from the repo dev2. Then in both repositories move all subdirectories one level up and remove directories dev1 and dev2.

cp -a repo_c dev1
cp -a repo_c dev2

cd dev1
git rm -rf dev2
cd dev1
git mv * ..
cd ..
git rm -rf dev1
git commit -m "Restructure repository"

Repeat the same for dev2 exchanging dev2 and dev1.