Nginx: Prevent /index from being appended to the root URL with .html rewrite rule

I'm serving a static HTML site with Nginx using the following configuration:

server {
    # some configs

    # Web root and file handling
    location / {
        root /var/lib/jenkins/workspace/test;
        index index.html index.htm;
        try_files $uri $uri.html $uri/ /index.html;
    }
}

I want to remove .html from the URLs, so I added this rewrite rule:

location ~ ^/(.*)\.html$ {
    rewrite ^/(.*)\.html$ /$1 permanent;
}

This works fine for pages like /test.html, which are rewritten to /test. However, whenever I access the root URL /, the browser displays /index in the address bar, which is not what I want. I want the root URL to remain as /.

How can I prevent /index from being appended to the root URL while keeping the .html rewrite for other pages?

Solution

This occurs because the index nginx directive performs an internal redirect when it locates an index file, as explained in the documentation:

It should be noted that using an index file causes an internal redirect, and the request can be processed in a different location. For example, with the following configuration:
location = / {
    index index.html;
}
location / {
    ...
}
a / request will actually be processed in the second location as /index.html.

The internal redirect from the root URL / to /index.html results in the request being processed by your regex location, which then returns an HTTP 301 redirect to the /index URL. To prevent this behavior, the simplest solution is to define a separate location specifically for the /index.html request:

location = /index.html {
    root /var/lib/jenkins/workspace/test;
}

A more advanced solution involves modifying your regex to exclude any index.html file, regardless of its level in a nested subdirectory structure:

location ~ ^(?<path>.*/(?!index\.html$)[^/]*)\.html$ {
    rewrite ^ $path permanent;
}