Add the Sphinx notfound page extension

[oraNod]

SUMMARY

Add https://sphinx-notfound-page.readthedocs.io/en/latest/installation.html

This is an attempt to fix the 404 page issues on read the docs.

ISSUE TYPE

• Bug, Docs Fix or other nominal change

COMPONENT NAME

• Docs

AWX VERSION

n/a

ADDITIONAL INFORMATION

follows up on #15668

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[oraNod]

I've added this to a project from my fork: https://oranod-awx.readthedocs.io/en/latest/

You can request a fake page name like foo.html and see the 404 page is there. The cowsay image is apparently getting picked up by the extension but the theme isn't applied.

[webknjaz]

Comparing https://oranod-awx.readthedocs.io/en/latest/ and https://oranod-awx.readthedocs.io/en/latest/foo.html:

- <title>Ansible AWX Documentation &mdash; Ansible AWX community documentation</title>
+ <title>Oh no! &mdash; Ansible AWX community documentation</title>
-       <link rel="stylesheet" href="_static/pygments.css" type="text/css" />
+       <link rel="stylesheet" href="/en/latest/_CascadingStyleSheet('_static/pygments.css', priority=200, rel='stylesheet', type='text/css')" type="text/css" />
-       <link rel="stylesheet" href="_static/css/ansible.css" type="text/css" />
+       <link rel="stylesheet" href="/en/latest/_CascadingStyleSheet('_static/css/ansible.css', priority=200, rel='stylesheet', type='text/css')" type="text/css" />
-       <link rel="stylesheet" href="_static/css/rtd-ethical-ads.css" type="text/css" />
+       <link rel="stylesheet" href="/en/latest/_CascadingStyleSheet('_static/css/rtd-ethical-ads.css', priority=500, rel='stylesheet', type='text/css')" type="text/css" />
-     <link rel="shortcut icon" href="_static/images/Ansible-Mark-RGB_Black.png"/>
+     <link rel="shortcut icon" href="/en/latest/_static/images/Ansible-Mark-RGB_Black.png"/>
    <!--[if lt IE 9]>
-     <script src="_static/js/html5shiv.min.js"></script>
+     <script src="/en/latest/_static/js/html5shiv.min.js"></script>
    <![endif]-->
  
-         <script src="_static/jquery.js?v=5d32c60e"></script>
+         <script src="/en/latest/_static/jquery.js?v=5d32c60e"></script>
-         <script src="_static/_sphinx_javascript_frameworks_compat.js?v=2cd50e6c"></script>
+         <script src="/en/latest/_static/_sphinx_javascript_frameworks_compat.js?v=2cd50e6c"></script>
-         <script src="_static/documentation_options.js?v=a9b6e813"></script>
+         <script src="/en/latest/_static/documentation_options.js?v=a9b6e813"></script>
-         <script src="_static/doctools.js?v=888ff710"></script>
+         <script src="/en/latest/_static/doctools.js?v=888ff710"></script>
-         <script src="_static/sphinx_highlight.js?v=dc90522c"></script>
+         <script src="/en/latest/_static/sphinx_highlight.js?v=dc90522c"></script>
-     <script src="_static/js/theme.js"></script>
+     <script src="/en/latest/_static/js/theme.js"></script>

I'm not sure why _CascadingStyleSheet() is leaking into the rendered HTML output. I think I saw this before, but never looked deep. The theme demo seems to be fine: https://sphinx-ansible-theme.readthedocs.io/en/latest/foo.html.

I think there's some incompatibility between versions of CPython, Sphinx and the underlying sphinx-rtd-theme. Somebody will probably have to bisect it.

readthedocs/sphinx-notfound-page#224 mentions the same problem and ansible/ansible-documentation#678 links ansible/ansible-documentation@9d4c6db that suggests that changing what settings are used might be the fix: https://github.com/ansible/ansible-documentation/pull/827/files#diff-de16707d76a94c258b2d4ba2b8f95910db018b923e2b4834dacf47c8964b2a90R340.

[webknjaz]

@oraNod you must always use the same environment to update constraints files. The AWX folks do this in their container for consistency. Plus, the updater script won't generate path changes back and forth in the comment lines below.