Doc builds are suddenly failing

[kurtmckee]

Issue

Scheduled doc builds have started failing with this warning as of today:

<unknown>:1: WARNING: py:data reference target not found: typing.Union [ref.data]
<unknown>:1: WARNING: py:data reference target not found: typing.Union [ref.data]
<unknown>:1: WARNING: py:data reference target not found: typing.Union [ref.data]

I've been able to narrow this down to these files by searching for the word "union" in the generated HTML:

• docs/plugins_api.rst
• src/tox/config/sets.py:ConfigSet.add_config()

    def add_config(  # noqa: PLR0913
        self,
        keys: str | Sequence[str],
        of_type: type[V],
        default: Callable[[Config, str | None], V] | V,
        desc: str,
        post_process: Callable[[V], V] | None = None,
        factory: Factory[Any] | None = None,
    ) -> ConfigDynamicDefinition[V]:

However, I haven't been able to figure out why this is suddenly triggering an issue, nor have I figured out what can be done to resolve the problem.

I'm opening this issue simply to note what I've found about the issue so far. I won't have additional time to drive this issue to closure, unfortunately.

Environment

Provide at least:

• OS: GitHub Actions, running on Ubuntu and Windows

[cclauss]

astral-sh/setup-uv@v6 --> astral-sh/setup-uv@v7

• Bump astral-sh/setup-uv from 6 to 7 #3620

[kurtmckee]

What's the connection to this issue, Christian?

[cclauss]

In the past 24 hours, we have moved from python3.14.0rc3 to python3.14.0 and setup-uv has issued a new release to deal with that upgrade.

• Bump astral-sh/setup-uv from 6 to 7 #3620 has been merged.

[kurtmckee]

Those aren't related.

I'm seeing this locally, too, on Python 3.13. I'm also seeing this failure in my personal tox repo action runs, which is 3 weeks behind main and doesn't include the setup-uv actions update.

[cclauss]

typing.Union [ref.data]

• typing.Union does not support attribute assignment post gh-105511 python/cpython#132139

[gaborbernat]

Wonder where this is done 🤔

[gaborbernat]

tox-dev/sphinx-argparse-cli#252 squashed one, let's see the Union now 🤔

[gaborbernat]

This will be tox-dev/sphinx-autodoc-typehints#569, mostly due to python/cpython#105499.

❯ python3.14 -c 'from typing import Union; print(Union[int, str], int | str)'
int | str int | str

❯ python3.13 -c 'from typing import Union; print(Union[int, str], int | str)'
typing.Union[int, str] int | str

❯ sphobjinv su ./objects.inv Union

Project: Python
Version: 3.13

17127 objects in inventory.

-------------------------------------------------------------------------------------------------------------

7 results found at/above current threshold of 75.

:py:class:`ctypes.BigEndianUnion`
:py:class:`ctypes.LittleEndianUnion`
:py:class:`ctypes.Union`
:py:method:`frozenset.union`
:py:class:`types.UnionType`
:py:data:`typing.Union`
:std:label:`types-union`

❯ sphobjinv su ./objects.inv.1 Union

Project: Python
Version: 3.14

17836 objects in inventory.

-------------------------------------------------------------------------------------------------------------

7 results found at/above current threshold of 75.

:py:class:`ctypes.BigEndianUnion`
:py:class:`ctypes.LittleEndianUnion`
:py:class:`ctypes.Union`
:py:method:`frozenset.union`
:py:class:`types.UnionType`
:py:class:`typing.Union`
:std:label:`types-union`