RTD docs build has been failing since Aug 2 2025

[brianschubert]

Read the Docs builds have been failing since 82ad62c (build).

The "latest" docs are still at the previous commit, e8147f2: https://mypy.readthedocs.io/en/latest/

Build history: https://app.readthedocs.org/projects/mypy/builds/

Traceback from the failing builds:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/envs/latest/lib/python3.11/site-packages/sphinx/registry.py", line 541, in load_extension
    mod = import_module(extname)
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/docs/.asdf/installs/python/3.11.12/lib/python3.11/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/docs/source/html_builder.py", line 14, in <module>
    from mypy.main import define_options
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/mypy/main.py", line 16, in <module>
    from mypy import build, defaults, state, util
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/mypy/build.py", line 42, in <module>
    import mypy.semanal_main
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/mypy/semanal_main.py", line 37, in <module>
    from mypy.checker import FineGrainedDeferredNode
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/mypy/checker.py", line 12, in <module>
    import mypy.checkexpr
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/mypy/checkexpr.py", line 15, in <module>
    import mypy.errorcodes as codes
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/checkouts/latest/mypy/errorcodes.py", line 11, in <module>
    from mypy_extensions import mypyc_attr
ModuleNotFoundError: No module named 'mypy_extensions'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/envs/latest/lib/python3.11/site-packages/sphinx/cmd/build.py", line 414, in build_main
    app = Sphinx(
          ^^^^^^^
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/envs/latest/lib/python3.11/site-packages/sphinx/application.py", line 291, in __init__
    self.setup_extension(extension)
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/envs/latest/lib/python3.11/site-packages/sphinx/application.py", line 489, in setup_extension
    self.registry.load_extension(self, extname)
  File "/home/docs/checkouts/readthedocs.org/user_builds/mypy/envs/latest/lib/python3.11/site-packages/sphinx/registry.py", line 544, in load_extension
    raise ExtensionError(
sphinx.errors.ExtensionError: Could not import extension docs.source.html_builder (exception: No module named 'mypy_extensions')