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- from __future__ import annotations
-
- import contextlib
- import os
- import sys
- from typing import TYPE_CHECKING, TypeVar, Union
-
- from more_itertools import unique_everseen
-
- if TYPE_CHECKING:
- from typing_extensions import TypeAlias
-
- StrPath: TypeAlias = Union[str, os.PathLike[str]] # Same as _typeshed.StrPath
- StrPathT = TypeVar("StrPathT", bound=Union[str, os.PathLike[str]])
-
-
- def ensure_directory(path):
- """Ensure that the parent directory of `path` exists"""
- dirname = os.path.dirname(path)
- os.makedirs(dirname, exist_ok=True)
-
-
- def same_path(p1: StrPath, p2: StrPath) -> bool:
- """Differs from os.path.samefile because it does not require paths to exist.
- Purely string based (no comparison between i-nodes).
- >>> same_path("a/b", "./a/b")
- True
- >>> same_path("a/b", "a/./b")
- True
- >>> same_path("a/b", "././a/b")
- True
- >>> same_path("a/b", "./a/b/c/..")
- True
- >>> same_path("a/b", "../a/b/c")
- False
- >>> same_path("a", "a/b")
- False
- """
- return normpath(p1) == normpath(p2)
-
-
- def normpath(filename: StrPath) -> str:
- """Normalize a file/dir name for comparison purposes."""
- # See pkg_resources.normalize_path for notes about cygwin
- file = os.path.abspath(filename) if sys.platform == 'cygwin' else filename
- return os.path.normcase(os.path.realpath(os.path.normpath(file)))
-
-
- @contextlib.contextmanager
- def paths_on_pythonpath(paths):
- """
- Add the indicated paths to the head of the PYTHONPATH environment
- variable so that subprocesses will also see the packages at
- these paths.
-
- Do this in a context that restores the value on exit.
-
- >>> getfixture('monkeypatch').setenv('PYTHONPATH', 'anything')
- >>> with paths_on_pythonpath(['foo', 'bar']):
- ... assert 'foo' in os.environ['PYTHONPATH']
- ... assert 'anything' in os.environ['PYTHONPATH']
- >>> os.environ['PYTHONPATH']
- 'anything'
-
- >>> getfixture('monkeypatch').delenv('PYTHONPATH')
- >>> with paths_on_pythonpath(['foo', 'bar']):
- ... assert 'foo' in os.environ['PYTHONPATH']
- >>> os.environ.get('PYTHONPATH')
- """
- nothing = object()
- orig_pythonpath = os.environ.get('PYTHONPATH', nothing)
- current_pythonpath = os.environ.get('PYTHONPATH', '')
- try:
- prefix = os.pathsep.join(unique_everseen(paths))
- to_join = filter(None, [prefix, current_pythonpath])
- new_path = os.pathsep.join(to_join)
- if new_path:
- os.environ['PYTHONPATH'] = new_path
- yield
- finally:
- if orig_pythonpath is nothing:
- os.environ.pop('PYTHONPATH', None)
- else:
- os.environ['PYTHONPATH'] = orig_pythonpath
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