Running Sphinx v9.0.4
loading translations [en]... done
making output directory... done
Converting `source_suffix = '.rst'` to `source_suffix = {'.rst': 'restructuredtext'}`.
[autosummary] generating autosummary for: changelog.rst, index.rst, traits_api_reference/base_trait_handler.rst, traits_api_reference/constants.rst, traits_api_reference/ctrait.rst, traits_api_reference/ctraits.rst, traits_api_reference/editor_factories.rst, traits_api_reference/has_traits.rst, traits_api_reference/index.rst, traits_api_reference/interface_checker.rst, ..., traits_user_manual/debugging.rst, traits_user_manual/deferring.rst, traits_user_manual/defining.rst, traits_user_manual/index.rst, traits_user_manual/installation.rst, traits_user_manual/internals.rst, traits_user_manual/intro.rst, traits_user_manual/listening.rst, traits_user_manual/notification.rst, traits_user_manual/testing.rst
loading intersphinx inventory 'pyface' from https://docs.enthought.com/pyface/objects.inv ...
loading intersphinx inventory 'python' from https://docs.python.org/3/objects.inv ...
loading intersphinx inventory 'traitsui' from https://docs.enthought.com/traitsui/objects.inv ...
building [mo]: targets for 0 po files that are out of date
writing output... 
building [html]: targets for 46 source files that are out of date
updating environment: [new config] 46 added, 0 changed, 0 removed
reading sources... [  2%] changelog
reading sources... [  4%] index
reading sources... [  7%] traits_api_reference/base_trait_handler
reading sources... [  9%] traits_api_reference/constants
reading sources... [ 11%] traits_api_reference/ctrait
reading sources... [ 13%] traits_api_reference/ctraits
reading sources... [ 15%] traits_api_reference/editor_factories
reading sources... [ 17%] traits_api_reference/has_traits
reading sources... [ 20%] traits_api_reference/index
reading sources... [ 22%] traits_api_reference/interface_checker
reading sources... [ 24%] traits_api_reference/trait_base
reading sources... [ 26%] traits_api_reference/trait_converters
reading sources... [ 28%] traits_api_reference/trait_dict_object
reading sources... [ 30%] traits_api_reference/trait_errors
reading sources... [ 33%] traits_api_reference/trait_factory
reading sources... [ 35%] traits_api_reference/trait_handler
reading sources... [ 37%] traits_api_reference/trait_handlers
reading sources... [ 39%] traits_api_reference/trait_list_object
reading sources... [ 41%] traits_api_reference/trait_notifiers
reading sources... [ 43%] traits_api_reference/trait_numeric
reading sources... [ 46%] traits_api_reference/trait_set_object
reading sources... [ 48%] traits_api_reference/trait_type
reading sources... [ 50%] traits_api_reference/trait_types
reading sources... [ 52%] traits_api_reference/traits
reading sources... [ 54%] traits_api_reference/traits.adaptation
reading sources... [ 57%] traits_api_reference/traits.etsconfig
reading sources... [ 59%] traits_api_reference/traits.observation
reading sources... [ 61%] traits_api_reference/traits.testing
reading sources... [ 63%] traits_api_reference/traits.util
reading sources... [ 65%] traits_api_reference/traits_listener
reading sources... [ 67%] traits_api_reference/version
reading sources... [ 70%] traits_tutorial/index
reading sources... [ 72%] traits_tutorial/introduction
reading sources... [ 74%] traits_user_manual/advanced
reading sources... [ 76%] traits_user_manual/appendix
reading sources... [ 78%] traits_user_manual/custom
reading sources... [ 80%] traits_user_manual/debugging
reading sources... [ 83%] traits_user_manual/deferring
reading sources... [ 85%] traits_user_manual/defining
reading sources... [ 87%] traits_user_manual/index
reading sources... [ 89%] traits_user_manual/installation
reading sources... [ 91%] traits_user_manual/internals
reading sources... [ 93%] traits_user_manual/intro
reading sources... [ 96%] traits_user_manual/listening
reading sources... [ 98%] traits_user_manual/notification
reading sources... [100%] traits_user_manual/testing
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
copying assets... 
copying downloadable files... [ 14%] ../../examples/introduction/0_introduction.py
copying downloadable files... [ 29%] ../../examples/introduction/1_validation.py
copying downloadable files... [ 43%] ../../examples/introduction/2_initialization.py
copying downloadable files... [ 57%] ../../examples/introduction/3_observation.py
copying downloadable files... [ 71%] ../../examples/introduction/4_properties.py
copying downloadable files... [ 86%] ../../examples/introduction/5_documentation.py
copying downloadable files... [100%] ../../examples/introduction/6_visualization.py
copying static files... 
Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/language_data.js
Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/basic.css
Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/documentation_options.js
Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/enthought.css
Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/copybutton.js
copying static files: done
copying extra files... 
copying extra files: done
copying assets: done

Theme error!

Versions
========

* Platform:         linux; (Linux-6.11.0-1018-azure-x86_64-with-glibc2.39)
* Python version:   3.13.11 (CPython)
* Sphinx version:   9.0.4
* Docutils version: 0.22.3
* Jinja2 version:   3.1.6
* Pygments version: 2.19.2

Last Messages
=============

    Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/enthought.css
    Writing evaluated template result to /home/runner/work/traits/traits/docs/build/_static/copybutton.js
    copying static files: done
    copying extra files...
    copying extra files: done
    copying assets: done

    writing output... [  2%]
    changelog

Loaded Extensions
=================

* sphinx.ext.mathjax (9.0.4)
* alabaster (1.0.0)
* sphinxcontrib.applehelp (2.0.0)
* sphinxcontrib.devhelp (2.0.0)
* sphinxcontrib.htmlhelp (2.1.0)
* sphinxcontrib.serializinghtml (2.0.0)
* sphinxcontrib.qthelp (2.0.0)
* sphinx.ext.autodoc (9.0.4)
* sphinx.ext.autosummary (9.0.4)
* sphinx.ext.coverage (9.0.4)
* sphinx.ext.githubpages (9.0.4)
* sphinx.ext.intersphinx (9.0.4)
* sphinx.ext.napoleon (9.0.4)
* sphinx.ext.viewcode (9.0.4)
* sphinx_copybutton (0.5.2)
* traits.util.trait_documenter (unknown version)

Traceback
=========

      File "/opt/hostedtoolcache/Python/3.13.11/x64/lib/python3.13/site-packages/sphinx/builders/html/__init__.py", line 1229, in handle_page
        raise ThemeError(msg) from exc
    sphinx.errors.ThemeError: An error happened in rendering the page changelog.
    Reason: TypeError("argument of type '_CascadingStyleSheet' is not iterable")


The full traceback has been saved in:
/tmp/sphinx-err-5b2s48rk.log

To report this error to the developers, please open an issue at <https://github.com/sphinx-doc/sphinx/issues/>. Thanks!
Please also report this if it was a user error, so that a better error message can be provided next time.
writing output... [  2%] changelog
Error: Process completed with exit code 2.