git subtree split error: You need to run this command from the toplevel of the working tree

Question

I have a git repo in /srv/git/mysite.git.

Workdir is set to

/srv/www/mysite

in git /srv/git/mysite.git/config:

[core] repositoryformatversion = 0
filemode = false
bare = false
worktree = /srv/www/mysite

[receive] denyCurrentBranch = updateInstead

I would like to split with subtree the directory content at:

/srv/www/mysite/mysubsite

to branch mysubsite.

When I execute:

cd /srv/git/mysite.git
git subtree split --prefix=mysubsite -b mysubsite

I get error

You need to run this command from the toplevel of the working tree.

It seems this thread has related info about my problem: http://git.661346.n2.nabble.com/git-users-Problem-using-detached-worktrees-with-commands-implemented-in-scripts-td7597786.html

I tried the following:

export GIT_WORK_TREE=/srv/www/mysite

export GIT_DIR=/srv/git/mysite.git

cd /srv/www/mysite

git subtree split --prefix=mysubsite -b mysubsite

I get error again:

You need to run this command from the toplevel of the working tree.

How can I fix this?

Answer 1

Works for me, export GIT_DIR was enough.

$ git --version 
git version 2.11.0

Also this works:

$ cd /srv/www/mysite
$ git --git-dir=/srv/git/mysite.git subtree split --prefix=mysubsite -b mysubsite