Regression with 10db540 and custom directive incorrectly warning about circular inclusion

Describe the bug

Hello,

Via bisection I have found that 10db540e9824a3747aa71947d0d4b039851172c3 causes a regression with zuul-sphinx, incorrectly warning about circular inclusion.

This plugin looks as README RST files in subdirectories and builds overview pages. It seems somehow this has started causing docutils to show a circular reference warning.

There has been some discussion of this in https://sourceforge.net/p/docutils/bugs/459/ but it still remains unclear what is happening.

Running the build with Sphinx 5.3 produces the output

Warning, treated as error:
/home/iwienand/tmp/sphinx/zuul-jobs/doc/source/container-roles.rst:3:circular inclusion in "include" directive: roles/build-docker-image/common.rst < roles/build-docker-image/common.rst < roles/build-container-image/common.rst < roles/build-container-image/README.rst

These are not recursively included, what is actually happening is that the same file (common.rst) is included from multiple README files, which themselves are included (serially) in a parent document. e.g.

container-roles.rst
 .. include:: build-container-image/README.rst
   .. include:: build-container-image/common.rst
 .. include:: build-docker-image/README.rst
   .. include:: build-container-image/common.rst

It is the second inclusion of common.rst here that triggers this. Why this change affects this, I frankly have no idea!

This is some sort of weird interaction with the docutils 0.17 releases. If I downgrade to docutils 0.16, the problem does not occur, and if I force upgrade to 0.18 it also does not occur. However, we are stuck on 0.17 because sphinx_rtd_theme is currently capped there.

zuul-sphinx is available at the above, but it all boils down to just the single file https://opendev.org/zuul/zuul-sphinx/src/branch/master/zuul_sphinx/zuul.py. The file that is causing problems is https://opendev.org/zuul/zuul-jobs/raw/branch/master/doc/source/container-roles.rst

How to Reproduce

git clone https://opendev.org/zuul/zuul-jobs
cd zuul-jobs
# This project has pinned itself to 5.2.3 to avoid this issue.  Remove the pin
sed -i 's/^sphinx<.*//' ./doc/requirements.txt
tox -e docs

To replicate with the commit in question reverted

git clone https://opendev.org/zuul/zuul-jobs
git clone https://github.com/sphinx-doc/sphinx.git
pushd sphinx
git checkout v5.3.0
git revert --no-edit 10db540e9824a3747
popd
pushd zuul-jobs
# remove the pin of sphinx to 5.2.3
sed -i 's/^sphinx<.*//' ./doc/requirements.txt
# recreate tox environment
tox -re docs
# overwrite with the checkout version of sphinx
.tox/docs/bin/pip install -e ../sphinx
# rerun tox
tox -e docs

Environment Information

text Platform: linux; (Linux-5.19.6-200.fc36.x86_64-x86_64-with-glibc2.35) Python version: 3.10.6 (main, Aug 2 2022, 00:00:00) [GCC 12.1.1 20220507 (Red Hat 12.1.1-1)]) Python implementation: CPython Sphinx version: 5.3.0 Docutils version: 0.17.1 Jinja2 version: 3.1.2

Sphinx extensions

No response

Additional context

No response

Start with zuul_sphinx/zuul.py and the container-roles.rst reproduction described in the issue. Run the documented tox docs build with Sphinx 5.3 and Docutils 0.17.1, then compare it with Docutils 0.16, 0.18, and the reverted 10db540 change. Done means the repeated non-recursive include no longer produces a circular inclusion warning.