uv python list fails if a pyenv-win install is included in the windows registry

[DavidCEllis]

If a version of python is installed via pyenv with the --register flag then subsequently uv will fail to list python installs as it attempts to query metadata of a file that does not exist.

It looks like this is caused because uv makes the assumption that py --list-paths will return paths with only <major>.<minor> version information while pyenv installs are shown with <major>.<minor>.<micro>¹. The regex is then capturing the <micro> part of the version as part of the path to the python executable.

uv/crates/uv-python/src/py_launcher.rs

Lines 36 to 39 in bbcd10d

	static PY_LIST_PATHS: LazyLock<Regex> = LazyLock::new(|| {
	// Without the `R` flag, paths have trailing \r
	Regex::new(r"(?mR)^ -(?:V:)?(\d).(\d+)-?(?:arm)?\d*\s*\*?\s*(.*)$").unwrap()
	});

Commands:

pyenv install 3.12.5 --register
uv python list

Full output:

C:\>uv --version
uv 0.3.2 (c5440001c 2024-08-23)

C:\>py --list
No installed Pythons found!

C:\>uv python list
cpython-3.12.5-windows-x86_64-none     <download available>
cpython-3.11.9-windows-x86_64-none     <download available>
cpython-3.10.14-windows-x86_64-none    <download available>
cpython-3.9.19-windows-x86_64-none     <download available>
cpython-3.8.19-windows-x86_64-none     <download available>
pypy-3.7.13-windows-x86_64-none        <download available>

C:\>pyenv install 3.12.5 --register
:: [Info] ::  Mirror: https://www.python.org/ftp/python
:: [Installing] ::  3.12.5 ...
:: [Info] :: completed! 3.12.5

C:\>py --list-paths
 -V:3.12.5 *      C:\Users\ducks\.pyenv\pyenv-win\versions\3.12.5\python.exe

C:\>uv python list
error: Failed to query Python interpreter
  Caused by: failed to query metadata of file `C:\.5 *      C:\Users\ducks\.pyenv\pyenv-win\versions\3.12.5\python.exe`
  Caused by: The filename, directory name, or volume label syntax is incorrect. (os error 123)

Example of py --list-paths output with multiple versions of python installed and registered with pyenv and some regular installs.²

 -V:3.13.0rc1 *   C:\Users\ducks\.pyenv\pyenv-win\versions\3.13.0rc1\python.exe
 -V:3.12.5        C:\Users\ducks\.pyenv\pyenv-win\versions\3.12.5\python.exe
 -V:3.12.5-win32  C:\Users\ducks\.pyenv\pyenv-win\versions\3.12.5-win32\python.exe
 -V:3.12          C:\Users\ducks\AppData\Local\Programs\Python\Python312\python.exe
 -V:3.12-32       C:\Users\ducks\AppData\Local\Programs\Python\Python312-32\python.exe
 -V:3.11.9        C:\Users\ducks\.pyenv\pyenv-win\versions\3.11.9\python.exe
 -V:3.10.11       C:\Users\ducks\.pyenv\pyenv-win\versions\3.10.11\python.exe
 -V:3.9.13        C:\Users\ducks\.pyenv\pyenv-win\versions\3.9.13\python.exe
 -V:3.8.10        C:\Users\ducks\.pyenv\pyenv-win\versions\3.8.10\python.exe

Footnotes

1. It looks like py is just using the key names to get the version rather than the value of Version or SysVersion in the registry. ↩

2. This also lead to me finding out that pyenv-win registers 32bit python installs as 64bit which I've reported as a bug there. ↩

[charliermarsh]

Thank you!