bpo-40592: shutil.which will not return None anymore if ; is the last char in PATHEXT (GH-20088)

shutil.which will not return None anymore for empty str in PATHEXT
Empty PATHEXT will now be defaulted to _WIN_DEFAULT_PATHEXT
This commit is contained in:
Christopher Marchfelder 2020-10-23 12:08:24 +02:00 committed by GitHub
parent 345cd37abe
commit da6f098188
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3 changed files with 24 additions and 1 deletions

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@ -53,6 +53,9 @@ COPY_BUFSIZE = 1024 * 1024 if _WINDOWS else 64 * 1024
_USE_CP_SENDFILE = hasattr(os, "sendfile") and sys.platform.startswith("linux")
_HAS_FCOPYFILE = posix and hasattr(posix, "_fcopyfile") # macOS
# CMD defaults in Windows 10
_WIN_DEFAULT_PATHEXT = ".COM;.EXE;.BAT;.CMD;.VBS;.JS;.WS;.MSC"
__all__ = ["copyfileobj", "copyfile", "copymode", "copystat", "copy", "copy2",
"copytree", "move", "rmtree", "Error", "SpecialFileError",
"ExecError", "make_archive", "get_archive_formats",
@ -1415,7 +1418,9 @@ def which(cmd, mode=os.F_OK | os.X_OK, path=None):
path.insert(0, curdir)
# PATHEXT is necessary to check on Windows.
pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
pathext_source = os.getenv("PATHEXT") or _WIN_DEFAULT_PATHEXT
pathext = [ext for ext in pathext_source.split(os.pathsep) if ext]
if use_bytes:
pathext = [os.fsencode(ext) for ext in pathext]
# See if the given file matches any of the expected path extensions.

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@ -1849,6 +1849,23 @@ class TestWhich(BaseTest, unittest.TestCase):
rv = shutil.which(program, path=self.temp_dir)
self.assertEqual(rv, temp_filexyz.name)
# Issue 40592: See https://bugs.python.org/issue40592
@unittest.skipUnless(sys.platform == "win32", 'test specific to Windows')
def test_pathext_with_empty_str(self):
ext = ".xyz"
temp_filexyz = tempfile.NamedTemporaryFile(dir=self.temp_dir,
prefix="Tmp2", suffix=ext)
self.addCleanup(temp_filexyz.close)
# strip path and extension
program = os.path.basename(temp_filexyz.name)
program = os.path.splitext(program)[0]
with os_helper.EnvironmentVarGuard() as env:
env['PATHEXT'] = f"{ext};" # note the ;
rv = shutil.which(program, path=self.temp_dir)
self.assertEqual(rv, temp_filexyz.name)
class TestWhichBytes(TestWhich):
def setUp(self):

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@ -0,0 +1 @@
:func:`shutil.which` now ignores empty entries in :envvar:`PATHEXT` instead of treating them as a match.