How to sync all branches of two repositories (one in github and one in gitlab) preventing merge conflicts?

Question

Repository X.git is in gitlab with all development artifacts and respective branches I create Y.git in github using the following approach In a common server I do a mirror of gitlab

git clone --mirror http://gitlabserverdomain/user/X.git
cd X.git
git remote add githubrepoalias https://githubserverdomain/Y.git
git push -f --tags githubrepoalias refs/heads/*:refs/heads/*

Now I want to enable users to use either repositories for sometime and would like to sync either commits

These commits should not cause merge conflicts.

How do I do achieve the objective?

Answer 1

I see no way to prevent conflicts between changes done in GitHub and other changes done in GitLab. Try using hooks on the servers directly to minimize it.

Answer 2

Everything is possible :)

You just need to to somehow:

• define git fetch-ing both-ways
• make sync interval as short as possible (eg using web-hooks to trigger sync as soon as there is a new commit)

I've just tested with GitLab mirroring functionality: https://docs.gitlab.com/ee/workflow/repository_mirroring.html

I've defined both Push and Pull rules pointing to a GitHub repo, and it worked - changes are synchronised both ways.