uv managed python fails installing sasl dependency with python 3.9.18

[ignacio-amaya-rovio]

Summary

How to reproduce

uvx --python 3.9.18 sasl

Error

Error contains the following:

      [stderr]
      <string>:34: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
      <string>:35: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
      sasl/saslwrapper.cpp:624:10: fatal error: 'ios' file not found
        624 | #include "ios"
            |          ^~~~~
      1 error generated.
      error: command '/usr/bin/c++' failed with exit code 1

      hint: This usually indicates a problem with the package or the build environment.

Impact

Installing the same library with pyenv python 3.9.18 works fine. This prevents me migrating some projects to use uv.

Platform

macOS 15.3.2 arm64

Version

uv 0.6.3 (a0b9f22 2025-02-24)

Python version

Python 3.9.18

[zanieb]

When you use pyenv, I presume the package is still built from source? Can you share logs for that?

[ignacio-amaya-rovio]

With pyenv I set in ~/.config/uv/uv.toml the following setting so that it would use pyenv python:

python-preference = "only-system"

Then running the same command uvx --python 3.9.18 sasl I get the following:

❯ uvx --python 3.9.18 sasl
      Built sasl==0.3.1
Installed 2 packages in 18ms
The executable `sasl` was not found.
warning: Package `sasl` does not provide any executables.

Package was properly installed and a warning is printed as there is no executable as expected.