Name of Failure:

activate-authawsvenv.sh fails on windows-2022-latest-small hosts, because uv provisions CPython 3.15.0 and the locked pydantic-core==2.46.5 ships no cp315 wheel.

Link to task:

https://spruce.corp.mongodb.com/task/dot_net_driver_aws_auth_tests_windows__version~latest_os~windows_64_topology~standalone_framework~net100_aws_auth_tests_0961577b226da3716fd434cc9f77023b3fca020c_26_10_27_01_28_53

Context of when and why the failure occurred:

uv finds no usable interpreter on these Windows hosts, so it downloads the newest managed CPython, which is now 3.15.0. The auth_aws group pulls in pydantic-core through pyop → oic → pydantic-settings → pydantic. The root pyproject's no-build-package setting for pydantic-core (DRIVERS-3649) correctly stops a source build, so venv setup fails. Linux and macOS hosts are unaffected, because uv uses a system 3.10–3.12 interpreter there. The C# Driver MONGODB-AWS tasks on Windows have failed on every run since about 2026-10-22. The drivers-tools' repo own CI doesn't run test-auth-aws on Windows, so it stays green. Its Windows test-csfle also gets 3.15.0 but doesn't need pydantic-core.

pydantic-core 2.50.1 (2026-10-11) ships cp315 wheels for Windows.

Desired state: auth_aws venv setup succeeds on Windows hosts, and MONGODB-AWS tasks there pass.

Stack trace:

[2026/10/26 21:50:19.449] Using CPython 3.15.0
[2026/10/26 21:52:22.471] error: Distribution `pydantic-core==2.46.5 @ registry+https://pypi.org/simple` can't be installed because it is marked as `--no-build` but has no binary distribution