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