This folder contains a symlink called TTS to the parent folder:

lrwxr-xr-x  TTS -> ..

This is used to appease the distribute/setuptools gods. When the project was initially set up, the repository folder itself was considered a namespace, and development was done with sys.path hacks. This means if you tried to install TTS, setup.py would see the packages models, utils, layers... instead of TTS.models, TTS.utils...

Installing TTS would then pollute the package namespace with generic names like those above. In order to make things installable in both install and development modes (pip install /path/to/TTS and pip install -e /path/to/TTS), we needed to add an additional 'TTS' namespace to avoid this pollution. A virtual redirect using packages_dir in setup.py is not enough because it breaks the editable installation, which can only handle the simplest of package_dir redirects.

Our solution is to use a symlink in order to add the extra TTS namespace. In setup.py, we only look for packages inside tts_namespace (this folder), which contains a symlink called TTS pointing to the repository root. The final result is that setuptools.find_packages will find TTS.models, TTS.utils...

With this hack, pip install -e will then add a symlink to the tts_namespace in your site-packages folder, which works properly. It's important not to add anything else in this folder because it will pollute the package namespace when installing the project.

This does not work if you check out your project on a filesystem that does not support symlinks.