Unable to install mamba-ssm with uv

[kszlim]

# in an environment with all mamba-ssm requirements installed, cuda, torch, etc.
uv pip install mamba-ssm # will fail

uv version:
uv 0.2.11 on linux

Error:

uv pip install mamba-ssm
⠙ mamba-ssm==2.0.4                                                                                                                                                                                                                                            error: Failed to download and build `mamba-ssm==2.0.4`
  Caused by: Failed to build: `mamba-ssm==2.0.4`
  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 "/path/to/home/.cache/uv/environments-v0/.tmpnxysd8/lib/python3.12/site-packages/setuptools/build_meta.py", line 325, in get_requires_for_build_wheel
    return self._get_build_requires(config_settings, requirements=['wheel'])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/path/to/home/.cache/uv/environments-v0/.tmpnxysd8/lib/python3.12/site-packages/setuptools/build_meta.py", line 295, in _get_build_requires
    self.run_setup()
  File "/path/to/home/.cache/uv/environments-v0/.tmpnxysd8/lib/python3.12/site-packages/setuptools/build_meta.py", line 487, in run_setup
    super().run_setup(setup_script=setup_script)
  File "/path/to/home/.cache/uv/environments-v0/.tmpnxysd8/lib/python3.12/site-packages/setuptools/build_meta.py", line 311, in run_setup
    exec(code, locals())
  File "<string>", line 8, in <module>
ModuleNotFoundError: No module named 'packaging'

[kidrahahjo]

I get a similar error when I try to install with pip directly, I suspect this is unrelated to uv. But I will let the maintainers suggest

[Update]

When I manually install packaging, pip works but uv still can't resolve packaging

[kszlim]

I've managed to get it installed with pip before, it does require that you pip install packaging first though.

[konstin]

For packages like this one that doesn't declare its build dependencies, you need to install packaging manually and use --no-build-isolation.

[kszlim]

@konstin I believe that packaging is declared as a build dep here? But I could be misunderstanding.

Using uv as you've directed did manage to work for me, however, I'm trying to get it to work with pixi, which might need some work upstream. Thanks!

[konstin]

The install_requires are declared at the bottom of the setup.py, but packaging is imported at the top, before we get to install_requires. The solution is to add a pyproject.toml with a [build-system] table so uv can install the dependencies of setup.py before running setup.py. You can find more information on build backends here, many more details about the build-system vs. setup.py and how pyproject.toml solves it are described in PEP 517.

[zanieb]

See #2252 — build isolation will become the default in pip in the future too.