example.com and example.com/index.php showing as home page

I’m writing a short article regarding auditing a site for duplicate content and redirection issues.

It’s common for non-WordPress sites to unknowingly have multiple different URLs work as their home page (example.com, http://www.example.com, example.com/index.php, http://www.example.com/index.php, example.com/home/index.php, etc., etc.). I had always assumed that WordPress took care of this for me automatically – until I tried punching in my domain.

On my WordPress site (installed in root directory) both of the following URLs resolve and show identical content.

mydomain.com
mydomain.com/index.php

Yes – there is a canonical tag, so the chances of this getting marked as duplicate content by a search engine are pretty small – but this still bugs me. There are no internal or external links pointing to the index.php version of the home page, the only reason I found it was by manually typing it in.

I’ve read that the WordPress .htaccess allows this to prevent an infinite redirect loop.

Is there any way to avoid this situation, or it is required for using WordPress?