grpcio build fails (Python 3.13, Windows): client_side_weighted_round_robin.upb_minitable.c : fatal error C1083: Cannot open compiler generated file: '': Invalid argument

[SamuelMarks]

What version of gRPC and what language are you using?

1.62.1 with Python

Also tried with: https://pypi.org/project/grpcio/#history

• 1.59.3
• 1.58.0
• 1.57.0
• 1.56.2
• 1.55.3

What operating system (Linux, Windows,...) and version?

Windows 11

What runtime / compiler are you using (e.g. python version or version of gcc)

Python 3.13.0a5 with MSVC 19.39.33523

What did you do?

0. Open x64 Native Tools Command Prompt for VS 2022 (also tried with Developer Command Prompt for VS 2022)
1. Activate Python 3.13.0a5 virtualenv
2. Extend INCLUDE environment variable with location of Python.h
3. py -m pip install grpcio

What did you expect to see?

Build to work

What did you see instead?

client_side_weighted_round_robin.upb_minitable.c
  third_party\upb\upb/message/internal/array.h(123): warning C4334: '<<': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
  third_party\upb\upb/message/accessors.h(316): warning C4267: 'function': conversion from 'size_t' to 'int', possible loss of data
  Local\Temp\pip-install-r5xfmgbx\grpcio_a3fe1474c8d548e08cb988c668e52887\src\core\ext\upb-gen\envoy\extensions\load_balancing_policies\client_side_weighted_round_robin\v3\client_side_weighted_round_robin.upb_minitable.c : fatal error C1083: Cannot open compiler generated file: '': Invalid argument

stdout.log
stderr.log

Anything else we should know about your project / environment?

[XuanWang-Amos]

Hi, Python 3.13 is not officially supported yet, we'll add the support later this year.

[XuanWang-Amos]

Since it's related to core file, @yashykt or @veblush can one of you take a look?