git push with force

Recently on our team chat: “I removed the remote git branch and pushed again”. “Remove” was not necessary, he could have used “git push –force” or better “git push –force-with-lease” instead.

Why

The normal “git pushed” only works when the remote branch is contained in your local branch or in other words if your local branch is the same or ahead of the remote branch. When you still want to “overwrite” the remote branch with your local branch, use the “–force” option or the “–force-with-lease”.

Caution

When you collaborate with other team members on a remote branch, git push with force option may overwrite their work. “–force-with-lease” makes git check that the remote branch is in the state we expect it to be in before pushing the local branch, so you wouldn’t destroy work that you don’t know of.

When

We need to force push when

  • we changed our local branch history by rebasing or amanding
  • we need to “reset” the remote branch to our local branch

Summary

If you need to “overwrite” a remote branch with your local branch, use the “–force-with-lease” option.

How to split a git repository

Say your git repo consists of a subdirectory “app” and a subdirectory “database” (or “frontend” and “backend” or “team-a” and “team-b”) and you realize each directories content should be in its own repository. Here is how to split the repo.

To create a repo that consists of the content of the “database” dir and its history, execute

and then push it to a new remote:

This is what Gitlab states on a newly created project page. However in git push -u origin --all “-all” should be replaced with “–mirror” because “-all” pushes all local branches only so you would need to checkout all branches you want to keep. “–mirror” pushes remote branches, too.

In the same fashion apply “filter-branches” to the “app” directory.