.git may be a file instead of a directory

[sorrx]

Note: Also you can have a plain text file .git at the root of your working tree, containing gitdir: <path> to point at the real directory that has the repository. (source: https://git-scm.com/docs/gitrepository-layout )

I have a project, where this is the case and the GitRepositoryProvider does not work out of the box.

Simple fix:
In Provider/GitRepositoryProvider.php replace line 55
if (is_dir($path . DIRECTORY_SEPARATOR . '.git')) {
with
if (file_exists($path . DIRECTORY_SEPARATOR . '.git')) {

[dontub]

Thanks for reporting!