"RecursionError: maximum recursion depth exceeded" when extending header

[mateus2k2]

Hi, When I try to do:

{% extends "base.html" %}

{% block announce %}
  <!-- Add announcement here, including arbitrary HTML -->
{% endblock %} 

I get the error:

  File "<frozen _collections_abc>", line 620, in __rsub__
  File "<frozen _collections_abc>", line 830, in _from_iterable
  File "<frozen _collections_abc>", line 621, in <genexpr>
  File "<frozen _collections_abc>", line 833, in __contains__
  File "/usr/local/lib/python3.11/collections/__init__.py", line 1021, in __contains__
    return any(key in m for m in self.maps)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RecursionError: maximum recursion depth exceeded
ERROR   -  [21:22:44] An error happened during the rebuild. The server will appear stuck until build errors are resolved.

[kamilkrzyskow]

Hello @mateus2k2,
change the name of the overriden template to main.html, as you're extending base.html, so naming it the same creates an infinite loop.
Please re-read the section in the docs: https://squidfunk.github.io/mkdocs-material/customization/#overriding-blocks

Also please use the search feature before starting new discussions, duplicate of:

• How to enable announcements when using GitHub pages #5169

[mateus2k2]

I'am sorry, but I am getting confused. This is my structure:

main.html

{% extends "base.html" %}

{% block htmltitle %}
  <title>Lorem ipsum dolor sit amet</title>
{% endblock %} 

header.html

{% extends "base.html" %}

changing it to {% extends "base.html" %} or {% extends "main.html" %} does not work on header.html
Only {% extends "base.html" %} works on the main.html

[kamilkrzyskow]

Oh, then perhaps this isn't a duplicate, sorry.

You can only override blocks in main.html. If you're overriding partials, you can't extend base.html or main.html.
It is executed from top to bottom main.html -> base.html -> partials/*.html it can't go back up.

This is the allowed structure in header.html:
with comments: https://github.com/squidfunk/mkdocs-material/blob/master/src/templates/partials/header.html
minified: https://github.com/squidfunk/mkdocs-material/blob/master/material/templates/partials/header.html

If you want to override the announcement block then do it in main.html

[mateus2k2]

I see, to thought I used {% extends "base.html" %} in the header.html to keep the header as is and add stuff on top. But I think I understand now, thanks