Empty _sources directory created even with html_copy_source disabled #13888
Description
Describe the bug
Since 8.2.0 the html builder creates an empty _sources/ directory, even if html_copy_source is set to False. This was introduced by commit 285908a.
How to Reproduce
echo "" > index.rst
echo "html_copy_source = False" > conf.py
sphinx-build -M html . _build
ls -d _build/html/_sourcesEnvironment Information
Platform: linux; (Linux-6.1.0-0.deb11.21-amd64-x86_64-with-glibc2.41)
Python version: 3.13.7 (main, Aug 20 2025, 22:17:40) [GCC 14.3.0])
Python implementation: CPython
Sphinx version: 8.2.3
Docutils version: 0.21.2
Jinja2 version: 3.1.6
Pygments version: 2.19.2
Sphinx extensions
Additional context
No response