uv does not install dynamic build dependencies before preparing metadata

[sbidoul]

It seems get_requires_for_build_wheel is not invoked before prepare_metadata_for_build_wheel.

This means dynamic build dependencies are not installed before preparing metadata.

Here is a reproducer.

uv pip install -v --no-deps "odoo-addon-mis_builder @ git+https://github.com/OCA/mis-builder@16.0#subdirectory=setup/mis_builder"

This fails about an invalid Name metadata, where it should succeed. This is most likely because the dynamic build dependency setuptools-odoo which is declared in setup.py has not been installed in the build environment.

With setuptools, setup_requires entries are returned by get_requires_for_build_wheel and must be installed before preparing metadata.

[halflings]

This is maybe related to an issue I'm encountering (trying to install the LLM finetuning lib axolotl):

(.venv) ➜  axolotl-finetuning uv pip install "axolotl[flash-attn,deepspeed] @ git+https://github.com/OpenAccess-AI-Collective/axolotl"
 Updated https://github.com/OpenAccess-AI-Collective/axolotl (5a5d474)
 Updated https://github.com/huggingface/peft.git (8db74d4)                      error: Failed to download and build: flash-attn==2.5.0
  Caused by: Failed to build: flash-attn==2.5.0
  Caused by: Build backend failed to determine metadata through `prepare_metadata_for_build_wheel`:
--- stdout:

--- stderr:
Traceback (most recent call last):
  File "<string>", line 10, in <module>
  File "/tmp/.tmpSjTNqD/.venv/lib/python3.11/site-packages/setuptools/build_meta.py", line 366, in prepare_metadata_for_build_wheel
    self.run_setup()
  File "/tmp/.tmpSjTNqD/.venv/lib/python3.11/site-packages/setuptools/build_meta.py", line 480, in run_setup
    super().run_setup(setup_script=setup_script)
  File "/tmp/.tmpSjTNqD/.venv/lib/python3.11/site-packages/setuptools/build_meta.py", line 311, in run_setup
    exec(code, locals())
  File "<string>", line 9, in <module>
ModuleNotFoundError: No module named 'packaging'
---

Running "uv pip install packaging" separately doesn't resolve this.

[charliermarsh]

@sbidoul - Thank you for this. I thought it was safe to skip get_requires_for_build_wheel when using the default backend but clearly not! Will fix.

[stillmatic]

the minimal repro for this is uv pip install flash-attn (https://github.com/Dao-AILab/flash-attention/tree/main?tab=readme-ov-file#installation-and-features)

[charliermarsh]

I think the solutions may be different. mis_builder I can fix trivially by ensuring we call get_requires_for_build_wheel in all cases. But flash-attn is still failing...

python -m build . also fails on flash-attn, which makes me think it's a problem with the package's declared metadata. And in fact, it looks like their setup script requires packaging (https://github.com/Dao-AILab/flash-attention/blob/5cdabc2809095b98c311283125c05d222500c8ff/setup.py#L9C6-L9C15), but that's not going to be available at the time the script runs (since the script itself declares it as a dependency at the very bottom).

[ilkersigirci]

The official way to install flash-attn is using pip install flash-attn --no-build-isolation. Will there be similar feature for uv? I can't use the current state of uv for my ML projects, because it doesn't allow me to install flash-attn

[zanieb]

We might want to track that use-case in a separate issue.

[Taytay]

@zanieb : Done here: #1715