`site.getsitepackages` function returns a non-existent path (depending on the `prefixes` value).

[mbyrnepr2]

Bug report

Bug description:

Hi! 👋 My goal was to find the site-packages path for a venv on a machine (a 3rd-party SAST tool at work requires to know the site-packages location).

I'm probably misusing the site.getsitepackages function but nevertheless I thought that it shouldn't return a site-packages path before first checking it exists.

Thank you and have a good one!

import site


print(
    site.getsitepackages(prefixes=["/a/non/existant/venv/path"])
)

['/a/non/existant/venv/path/lib/python3.14/site-packages']

https://docs.python.org/3.15/library/site.html#site.getsitepackages

CPython versions tested on:

3.15

Operating systems tested on:

macOS

Linked PRs

• gh-156517: Clarify that site.getsitepackages() doesn't check for existance #156524
• [3.15] gh-156517: Clarify that site.getsitepackages() doesn't check for existance (GH-156524) #156648
• [3.14] gh-156517: Clarify that site.getsitepackages() doesn't check for existance (GH-156524) #156649
• [3.13] gh-156517: Clarify that site.getsitepackages() doesn't check for existance (GH-156524) #156650

[StanFromIreland]

Hi! Thanks for the report, however site.getsitepackages() just does path computations, and never checks for existence. That's left to site.addsitepackages(), which skips the candidates that don't exist.

However, I think this can be clarified in the documentation, so I wrote #156524. Could you please review?