Interaction with tox

[clint-lawrence]

tox doesn't pass LOCALAPPDATA to subcommands by default, so when calling py.exe from a tox command, it can't find any runtimes, even when they are installed.

I'm planning to raise in issue on the tox project to pass that env var on windows. Is there is anything else that is needed to ensure tox and py.exe work correctly together?

Background

Installed using version 20.1b1 as documented here https://www.python.org/downloads/release/pymanager-251b1/

Details

I have a python script that is called by tox. This script calls py.exe with a specific python version set. Running this script directly with py.exe works fine as expected. Something like:

import subprocess
subprocess.run(["py.exe", "-V:3.12", "-c", "pass"], check=True)

And a tox file

[testenv]
commands =
    python call_py.py

When running tox, the subprocess call to py.exe fails with following error.

❯ uvx tox
py: commands[0]> python call_py.py
[ERROR] No runtime installed that matches 3.12. Try running "py install 3.12".
Traceback (most recent call last):
  File "C:\Users\clawrence\dev\pymanager\call_py.py", line 3, in <module>
    subprocess.run(["py.exe", "-V:3.12", "-c", "pass"], check=True)
  File "C:\Users\clawrence\AppData\Roaming\uv\python\cpython-3.10.18-windows-x86_64-none\lib\subprocess.py", line 526, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['py.exe', '-V:3.12', '-c', 'pass']' returned non-zero exit status 2684354566.
py: exit 1 (0.80 seconds) C:\Users\clawrence\dev\pymanager> python call_py.py pid=19416
  py: FAIL code 1 (1.08=setup[0.28]+cmd[0.80] seconds)
  evaluation failed :( (1.16 seconds)

~\dev\pymanager via 🐍 v3.14.0 (installer) took 3s
❯ py -V:3.12 -c "pass"

~\dev\pymanager via 🐍 v3.14.0 (installer)
❯ py call_py.py

~\dev\pymanager via 🐍 v3.14.0 (installer)
❯

[zooba]

Hmm, that's a tough question, since a user can put any environment variable they like into their configuration.

The default configuration settings also use %AppData%, but nothing else that isn't PyManager-specific. I also see %TMP% (or %TEMP%) in the sources, and %WINDIR% and %PATH% (but only when installing a new runtime). %SystemRoot% is used to locate Powershell in the rare case that all the other ways of downloading files have failed or been disabled. All of these really need to be set for most Windows apps to be able to function, so it's likely that they're allowed through already.

[clint-lawrence]

Hmm, that's a tough question, since a user can put any environment variable they like into their configuration.

If someone changes the defaults, I think it is reasonable to expect them to also accommodate those changes in how they configure tox. So I don't think anything extra is needed in that case.

The default configuration settings also use %AppData%, but nothing else that isn't PyManager-specific. I also see %TMP% (or %TEMP%) in the sources, and %WINDIR% and %PATH% (but only when installing a new runtime). %SystemRoot% is used to locate Powershell in the rare case that all the other ways of downloading files have failed or been disabled. All of these really need to be set for most Windows apps to be able to function, so it's likely that they're allowed through already.

Yes, tox already passes all of those values you've listed by default.

Thanks for clarifying