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 _cygwin_patch(filename: StrPath): # pragma: nocover
"""
Contrary to POSIX 2008, on Cygwin, getcwd (3) contains
symlink components. Using
os.path.abspath() works around this limitation. A fix in os.getcwd()
would probably better, in Cygwin even more so, except
that this seems to be by design...
"""
return os.path.abspath(filename) if sys.platform == 'cygwin' else filename
def normpath(filename: StrPath) -> str:
"""Normalize a file/dir name for comparison purposes."""
return os.path.normcase(os.path.realpath(os.path.normpath(_cygwin_patch(filename))))
@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
|