Error when returning a nodes.section in a custom directive

[loichuder]

I have a very simple Sphinx extension that implement a custom directive that returns a new section:

from docutils.parsers.rst import Directive
from docutils import nodes


class TestDirective(Directive):
    def run(self):
        new_section = nodes.section()
        new_section += nodes.title(text="Title")
        return [new_section]

def setup(app):
    app.add_directive("test", TestDirective)

But whenever I try to include the directive in a Sphinx project:

test
====

.. test:: 

I get the following error:

Extension error (sphinx.environment.collectors.toctree):
Handler <bound method TocTreeCollector.process_doc of <sphinx.environment.collectors.toctree.TocTreeCollector object at 0x7f8e3ebed390>> for event 'doctree-read' threw an exception (exception: list index out of range)

I am still very new to docutils and custom Sphinx extensions so I guess I am doing something wrong but I don't have the skills to really dig deeper.

Ps: I am using Sphinx 8.1.3 but I get the same error with Sphinx 7.x