[CI/Build] Add support for Python 3.13

[mgoin]

FIX #12083

Tested that basic vllm serve works

uv venv --python 3.13 ~/venvs/py313
source ~/venvs/py313/bin/activate
VLLM_USE_PRECOMPILED=1 uv pip install -U -e . --torch-backend=cu128
vllm serve Qwen/Qwen3-0.6B
...
(APIServer pid=2520745) INFO:     Application startup complete.

Dependencies that are blockers for python 3.13 support:

• xformers (xformers==0.0.31 supports python 3.13, however this requires torch==2.7.1 https://github.com/facebookresearch/xformers/releases/tag/v0.0.31)
• ray (it seems blocking until 2.45 comes out [Core] Python 3.13 wheel ray-project/ray#49738 (comment))
• xgrammar (issue Python 3.13 wheel mlc-ai/xgrammar#193)
• torchaudio==2.5.1 (resolved by Update to torch==2.6.0 #12721)
• vllm-flash-attn (Add python 3.13 support to CMakeLists.txt flash-attention#47)

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[Ryp]

I think you'd also need a matching PR on https://github.com/vllm-project/flash-attention/blob/main/CMakeLists.txt#L22

Run locally with TORCH_CUDA_ARCH_LIST="Auto" VLLM_BUILD_DIR=build pip install -v --no-clean --no-build-isolation -e . and you should run into the error if you didn't patch this part.

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @mgoin.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[manueldeprada]

ray-project/ray#49738

ray already has 3.13 nightly builds, stable wheel coming with next release probably

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @mgoin.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[Ryp]

Can you please update the blocker list? Sound like xgrammar is not longer an issue since we're on 0.1.15 now: #14563
Also python 3.13 is now supported in flash attention as well!

[21m1n]

bumped into this error when i pip install vllm in a newly created environment.

python version 3.13.0

Collecting numba==0.60.0 (from vllm)
  Using cached numba-0.60.0.tar.gz (2.7 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  error: subprocess-exited-with-error
  
  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [24 lines of output]
      Traceback (most recent call last):
        File "/home/zimin/miniconda3/envs/vllm/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 389, in <module>
          main()
          ~~~~^^
        File "/home/zimin/miniconda3/envs/vllm/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 373, in main
          json_out["return_val"] = hook(**hook_input["kwargs"])
                                   ~~~~^^^^^^^^^^^^^^^^^^^^^^^^
        File "/home/zimin/miniconda3/envs/vllm/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 143, in get_requires_for_build_wheel
          return hook(config_settings)
        File "/tmp/pip-build-env-moyn66y8/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 334, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=[])
                 ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-moyn66y8/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 304, in _get_build_requires
          self.run_setup()
          ~~~~~~~~~~~~~~^^
        File "/tmp/pip-build-env-moyn66y8/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 522, in run_setup
          super().run_setup(setup_script=setup_script)
          ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-moyn66y8/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 320, in run_setup
          exec(code, locals())
          ~~~~^^^^^^^^^^^^^^^^
        File "<string>", line 51, in <module>
        File "<string>", line 48, in _guard_py_ver
      RuntimeError: Cannot install on Python version 3.13.2; only versions >=3.9,<3.13 are supported.
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× Getting requirements to build wheel did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

[mgoin]

Updated the list and it seems like ray is still going to be a blocker until 2.45 comes out ray-project/ray#49738 (comment)

[dan-and]

Also numba needs to be 0.62 to work with python 3.13

[manueldeprada]

@mgoin ray 2.45 is out :)