gitlab github sync

1. add github remote url 

git remote add github https://github.com/repo-name/testscript.git

git remote remove github https://github.com/repo-name/testscript.git

.git/config:

[remote "github"]
url = https://github.com/repo-name/testscript.git

fetch = +refs/heads/*:refs/remotes/origin/*

2. add gitlab remote url 

git remote add gitlab https://gitlab.com/repo-name/testscript.git

.git/config:

[remote "gitlab"]
url = https://gitlab.com/repo-name/testscript.git

fetch = +refs/heads/*:refs/remotes/origin/*

3. fetch from github

git fetch github

From https://github.com/repo-name/testscript.git  

 * [new branch]        main          -> github/main    

4. fetch from gitlab

git fetch gitlab

From https://gitlab.com/repo-name/testscript.git  

 * [new branch]        master          -> gitlab/master    

5. push gitlab branch master to github

git push -u github master    #push local branch master to github(remote repo).

ref: https://git-scm.com/book/ja/v2/Git-%E3%81%AE%E5%9F%BA%E6%9C%AC-%E3%83%AA%E3%83%A2%E3%83%BC%E3%83%88%E3%81%A7%E3%81%AE%E4%BD%9C%E6%A5%AD

git branch --set-upstream-to=github/main mbp-main

git fetch mbp-main

-refusing to merge unrelated histories

$ git merge --allow-unrelated-histories target_branch

# コミットを1まとめにしたい場合

$ git merge --allow-unrelated-histories --squash target_branch

reset の取り消し

git reset --soft HEAD@{1}

#when rename remote branch: feature/202203->main, update local branch:

git branch -m feature/202203 main
git fetch github

# set-upstream-to github/main mbp-main

git branch -u github/main mbp-main

#github/HEAD set to main

git remote set-head github -a