How to get Read the Docs to generate py-modindex.html?

[Charles Ross]

Since I appear to be experiencing one of the few times that Stack Overflow hasn’t provided any quick answers to a problem (http://stackoverflow.com/questions/39197037/how-to-get-read-the-docs-to-generate-py-modindex-html <http://stackoverflow.com/questions/39197037/how-to-get-read-the-docs-to-generate-py-modindex-html>), I’ll try posting my question here and see if anyone has a suggestion.

I'm trying to get Read the Docs to generate the `py-modindex.html` file. Research into a related question lead me to the following setup:

- `setup.py` in the project directory has the following contents, which were the minimum needed to get `pytest` to work and haven't been changed since I got that part of my project working:

        import setuptools

        setuptools.setup(
            name='polygons',
            packages=setuptools.find_packages(),
        )

- `docs/requirements.txt` contains a single line:

        sphinx-autodoc-annotation

- The Read the Docs repository URL points to my repository (https://github.com/chivalry/polygons).
- The RtD setting for "Install your project inside a virtualenv using setup.py install" is checked.
- The RtD setting for "Requirements file" points to `docs/requirements.txt`.

The "Module Index" link gets included in `index.html` (http://polygons.readthedocs.io/en/latest/), but the `py-modindex.html` file is missing.

My understanding is that with the virtualenv setting above, RtD will use the `setup.py` file to install the project so that Sphinx can read the documentation found in the Python docstrings. I'm using function annotations and would like `sphyinx-autodoc-annotation` to make use of those when creating the built docs files. All of this works splendidly on my local machine when I run `make html` while in the `docs` folder. Now I'm trying to get it to work on Read the Docs.

Thanks,
Chuck