Using git to merge two directories with common parent (but different SHA1)

Question

In our project somebody took a copy of the code. They started a new git repository in their directory and continued their work there. Meanwhile the work on our main project

Answer 1

Assume you are now in the repo include A---B---C---D.

You need first to add the other repo into this repo use the command.

$git remote add another_repo 
$git fetch another_repo

Then you can merge, use

$git merge another_repo/master