bpo-35755: shutil.which() uses os.confstr("CS_PATH") (GH-12858)
shutil.which() and distutils.spawn.find_executable() now use
os.confstr("CS_PATH") if available instead of os.defpath, if the PATH
environment variable is not set.
Don't use os.confstr("CS_PATH") nor os.defpath if the PATH
environment variable is set to an empty string to mimick Unix 'which'
command behavior.
Changes:
* find_executable() now starts by checking for the executable in the
current working directly case. Add an explicit
"if not path: return None".
* Add tests for PATH='' (empty string), PATH=':' and for PATHEXT.diff --git a/Lib/distutils/spawn.py b/Lib/distutils/spawn.py
index 5387688..8883272 100644
--- a/Lib/distutils/spawn.py
+++ b/Lib/distutils/spawn.py
@@ -172,21 +172,32 @@
A string listing directories separated by 'os.pathsep'; defaults to
os.environ['PATH']. Returns the complete filename or None if not found.
"""
- if path is None:
- path = os.environ.get('PATH', os.defpath)
-
- paths = path.split(os.pathsep)
- base, ext = os.path.splitext(executable)
-
+ _, ext = os.path.splitext(executable)
if (sys.platform == 'win32') and (ext != '.exe'):
executable = executable + '.exe'
- if not os.path.isfile(executable):
- for p in paths:
- f = os.path.join(p, executable)
- if os.path.isfile(f):
- # the file exists, we have a shot at spawn working
- return f
- return None
- else:
+ if os.path.isfile(executable):
return executable
+
+ if path is None:
+ path = os.environ.get('PATH', None)
+ if path is None:
+ try:
+ path = os.confstr("CS_PATH")
+ except (AttributeError, ValueError):
+ # os.confstr() or CS_PATH is not available
+ path = os.defpath
+ # bpo-35755: Don't use os.defpath if the PATH environment variable is
+ # set to an empty string to mimick Unix which command behavior
+
+ # PATH='' doesn't match, whereas PATH=':' looks in the current directory
+ if not path:
+ return None
+
+ paths = path.split(os.pathsep)
+ for p in paths:
+ f = os.path.join(p, executable)
+ if os.path.isfile(f):
+ # the file exists, we have a shot at spawn working
+ return f
+ return None
diff --git a/Lib/distutils/tests/test_spawn.py b/Lib/distutils/tests/test_spawn.py
index 0d45538..f9ae69e 100644
--- a/Lib/distutils/tests/test_spawn.py
+++ b/Lib/distutils/tests/test_spawn.py
@@ -87,11 +87,52 @@
rv = find_executable(dont_exist_program , path=tmp_dir)
self.assertIsNone(rv)
- # test os.defpath: missing PATH environment variable
+ # PATH='': no match, except in the current directory
with test_support.EnvironmentVarGuard() as env:
- with mock.patch('distutils.spawn.os.defpath', tmp_dir):
- env.pop('PATH')
+ env['PATH'] = ''
+ with unittest.mock.patch('distutils.spawn.os.confstr',
+ return_value=tmp_dir, create=True), \
+ unittest.mock.patch('distutils.spawn.os.defpath',
+ tmp_dir):
+ rv = find_executable(program)
+ self.assertIsNone(rv)
+ # look in current directory
+ with test_support.change_cwd(tmp_dir):
+ rv = find_executable(program)
+ self.assertEqual(rv, program)
+
+ # PATH=':': explicitly looks in the current directory
+ with test_support.EnvironmentVarGuard() as env:
+ env['PATH'] = os.pathsep
+ with unittest.mock.patch('distutils.spawn.os.confstr',
+ return_value='', create=True), \
+ unittest.mock.patch('distutils.spawn.os.defpath', ''):
+ rv = find_executable(program)
+ self.assertIsNone(rv)
+
+ # look in current directory
+ with test_support.change_cwd(tmp_dir):
+ rv = find_executable(program)
+ self.assertEqual(rv, program)
+
+ # missing PATH: test os.confstr("CS_PATH") and os.defpath
+ with test_support.EnvironmentVarGuard() as env:
+ env.pop('PATH', None)
+
+ # without confstr
+ with unittest.mock.patch('distutils.spawn.os.confstr',
+ side_effect=ValueError,
+ create=True), \
+ unittest.mock.patch('distutils.spawn.os.defpath',
+ tmp_dir):
+ rv = find_executable(program)
+ self.assertEqual(rv, filename)
+
+ # with confstr
+ with unittest.mock.patch('distutils.spawn.os.confstr',
+ return_value=tmp_dir, create=True), \
+ unittest.mock.patch('distutils.spawn.os.defpath', ''):
rv = find_executable(program)
self.assertEqual(rv, filename)