mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-25 07:05:13 +00:00
40 lines
1.6 KiB
Python
40 lines
1.6 KiB
Python
"""
|
|
This is a Nix-specific module for discovering modules built with Nix.
|
|
|
|
The module recursively adds paths that are on `NIX_PYTHONPATH` to `sys.path`. In
|
|
order to process possible `.pth` files `site.addsitedir` is used.
|
|
|
|
The paths listed in `PYTHONPATH` are added to `sys.path` afterwards, but they
|
|
will be added before the entries we add here and thus take precedence.
|
|
|
|
Note the `NIX_PYTHONPATH` environment variable is unset in order to prevent leakage.
|
|
|
|
Similarly, this module listens to the environment variable `NIX_PYTHONEXECUTABLE`
|
|
and sets `sys.executable` to its value.
|
|
"""
|
|
import site
|
|
import sys
|
|
import os
|
|
import functools
|
|
|
|
paths = os.environ.pop('NIX_PYTHONPATH', None)
|
|
if paths:
|
|
functools.reduce(lambda k, p: site.addsitedir(p, k), paths.split(':'), site._init_pathinfo())
|
|
|
|
# Check whether we are in a venv or virtualenv.
|
|
# For Python 3 we check whether our `base_prefix` is different from our current `prefix`.
|
|
# For Python 2 we check whether the non-standard `real_prefix` is set.
|
|
# https://stackoverflow.com/questions/1871549/determine-if-python-is-running-inside-virtualenv
|
|
in_venv = (sys.version_info.major == 3 and sys.prefix != sys.base_prefix) or (sys.version_info.major == 2 and hasattr(sys, "real_prefix"))
|
|
|
|
if not in_venv:
|
|
executable = os.environ.pop('NIX_PYTHONEXECUTABLE', None)
|
|
prefix = os.environ.pop('NIX_PYTHONPREFIX', None)
|
|
|
|
if 'PYTHONEXECUTABLE' not in os.environ and executable is not None:
|
|
sys.executable = executable
|
|
if prefix is not None:
|
|
# Sysconfig does not like it when sys.prefix is set to None
|
|
sys.prefix = sys.exec_prefix = prefix
|
|
site.PREFIXES.insert(0, prefix)
|