Support flash attention flash-attn --no-build-isolation with uv sync #6437
Description
I get the following error despite installation flash attention was successful via uv add flash-attn --no-build-isolation. See #6402. Is there anyway to honor the no-build-isolation when doing uv sync? I imagine the idea is to mark the flash-attn dependencies somehow and run it with no-build-isolation after all the other dependencies have been installed.
pyproject.toml and uv.lock are here: https://gist.github.com/vwxyzjn/fba2c7ffac8e6c923ffe912a872ec9a8
open-instruct git:(uv) ✗ uv sync
Using Python 3.12.5
Creating virtualenv at: .venv
⠦ fire==0.6.0 error: Failed to download and build `flash-attn==2.6.3`
Caused by: Build backend failed to determine extra requires with `build_wheel()` with exit status: 1
--- stdout:
--- stderr:
Traceback (most recent call last):
File "<string>", line 14, in <module>
File "/home/costa/.cache/uv/builds-v0/.tmpLR2n19/lib/python3.12/site-packages/setuptools/build_meta.py", line 332, in get_requires_for_build_wheel
return self._get_build_requires(config_settings, requirements=[])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/costa/.cache/uv/builds-v0/.tmpLR2n19/lib/python3.12/site-packages/setuptools/build_meta.py", line 302, in _get_build_requires
self.run_setup()
File "/home/costa/.cache/uv/builds-v0/.tmpLR2n19/lib/python3.12/site-packages/setuptools/build_meta.py", line 502, in run_setup
super().run_setup(setup_script=setup_script)
File "/home/costa/.cache/uv/builds-v0/.tmpLR2n19/lib/python3.12/site-packages/setuptools/build_meta.py", line 318, in run_setup
exec(code, locals())
File "<string>", line 21, in <module>
ModuleNotFoundError: No module named 'torch'
---
Caused by: This error likely indicates that flash-attn==2.6.3 depends on torch, but doesn't declare it as a build dependency. If flash-attn==2.6.3 is a first-party package, consider adding torch to its `build-system.requires`. Otherwise, `uv pip install torch` into the environment and re-run with `--no-build-isolation`.