Build error with uv

[demidenm]

Unsure what this bug(?) classifies under, but adding here in the event it is helpful for someone else. I have been using uv environment management for python. My workflow worked fine 3-4 weeks ago. Today, I would get the error:

Using CPython 3.13.2
Creating virtual environment at: .venv
...
× Failed to build pyzmq==27.0.0
  ├─▶ The build backend returned an error
  ╰─▶ Call to scikit_build_core.build.build_wheel failed (exit status: 1)
...
/tmp/tmp476q9wkj/build/_src/_zmq.c:15:6: error: #error Cython requires Python 3.8+.
         15 |     #error Cython requires Python 3.8+.
            |      ^~~~~
      ninja: build stopped: subcommand failed.

      [stderr]

Forcing uv to use python 3.12 didnt resolve the issue. Tried several other things to no avail. Updating my pyproject.toml file by reverting to v.26.4.0 worked:
dependencies = [
"pyzmq==26.4.0", # avoids build error with 27.0.0
....
]

[minrk]

Can you share the os and arch and the exact command used? A full repro example would really help, too, if that's possible.

[demidenm]

Added a light repo which I use to setup an env: https://github.com/demidenm/bidssm_groupmodill . If you remove/comment out this line in the .toml file, it continuously caused the error.

Running on:

uname -a
Linux sh04-04n21.int 3.10.0-1160.119.1.el7.tuxcare.els17.x86_64 #1 SMP Mon Feb 24 04:58:14 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

The error occurs when I run the setup file:

bash setup_uv.sh