Failed to build docs: jinja2.exceptions.UndefinedError: 'None' has no attribute 'get'

[marek22k]

Hello,

I try to build the documentation for offline usage, but get a error:

marek@debian-builder:~/proguard/docs$ pipx inject mkdocs mkdocs-material
  injected package mkdocs-material into venv mkdocs
done! ✨ 🌟 ✨
marek@debian-builder:~/proguard/docs$ git describe 
v7.1.0-beta1-365-gfbcf41f
marek@debian-builder:~/proguard/docs$ mkdocs build
INFO    -  Cleaning site directory
INFO    -  Building documentation to directory: /home/marek/proguard/docs/html
INFO    -  The following pages exist in the docs directory, but are not included in the "nav" configuration:
             - index.md
             - downloads.md
             - results.md
WARNING -  Doc file 'downloads.md' contains a link 'license.md', but the target is not found among documentation files.
WARNING -  Doc file 'downloads.md' contains a link 'releasenotes.md', but the target is not found among documentation files.
WARNING -  Doc file 'manual/FAQ.md' contains a link 'manual/index.md', but the target 'manual/manual/index.md' is not found among documentation
           files.
WARNING -  Doc file 'manual/releasenotes.md' contains a link 'setup/upgrading.md', but the target 'manual/setup/upgrading.md' is not found among
           documentation files.
Traceback (most recent call last):
  File "/home/marek/.local/bin/mkdocs", line 8, in <module>
    sys.exit(cli())
             ^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/click/core.py", line 1161, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/click/core.py", line 1082, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/click/core.py", line 1697, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/click/core.py", line 1443, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/click/core.py", line 788, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/mkdocs/__main__.py", line 288, in build_command
    build.build(cfg, dirty=not clean)
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/mkdocs/commands/build.py", line 328, in build
    _build_theme_template(template, env, files, config, nav)
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/mkdocs/commands/build.py", line 103, in _build_theme_template
    output = _build_template(template_name, template, files, config, nav)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/mkdocs/commands/build.py", line 83, in _build_template
    output = template.render(context)
             ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/jinja2/environment.py", line 1295, in render
    self.environment.handle_exception()
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/jinja2/environment.py", line 942, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/material/templates/404.html", line 4, in top-level template code
    {% extends "main.html" %}
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/material/templates/main.html", line 4, in top-level template code
    {% extends "base.html" %}
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/material/templates/base.html", line 59, in top-level template code
    {% block fonts %}
^^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/material/templates/base.html", line 61, in block 'fonts'
    {% set text = config.theme.font.get("text", "Roboto") %}
^^^^^^^^^^^^^^^^^^^^^
  File "/home/marek/.local/pipx/venvs/mkdocs/lib/python3.11/site-packages/jinja2/utils.py", line 92, in from_obj
    if hasattr(obj, "jinja_pass_arg"):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
jinja2.exceptions.UndefinedError: 'None' has no attribute 'get'