Fix a couple refurb warnings (#4172)

pkg_resources/__init__.py

@@ -407,20 +407,18 @@ def get_provider(moduleOrReq):
     return _find_adapter(_provider_factories, loader)(module)
 
 
-def _macos_vers(_cache=[]):
-    if not _cache:
-        version = platform.mac_ver()[0]
-        # fallback for MacPorts
-        if version == '':
-            plist = '/System/Library/CoreServices/SystemVersion.plist'
-            if os.path.exists(plist):
-                with open(plist, 'rb') as fh:
-                    plist_content = plistlib.load(fh)
-                if 'ProductVersion' in plist_content:
-                    version = plist_content['ProductVersion']
-
-        _cache.append(version.split('.'))
-    return _cache[0]
+@functools.lru_cache(maxsize=None)
+def _macos_vers():
+    version = platform.mac_ver()[0]
+    # fallback for MacPorts
+    if version == '':
+        plist = '/System/Library/CoreServices/SystemVersion.plist'
+        if os.path.exists(plist):
+            with open(plist, 'rb') as fh:
+                plist_content = plistlib.load(fh)
+            if 'ProductVersion' in plist_content:
+                version = plist_content['ProductVersion']
+    return version.split('.')
 
 
 def _macos_arch(machine):
@@ -2422,12 +2420,9 @@ def _cygwin_patch(filename):  # pragma: nocover
     return os.path.abspath(filename) if sys.platform == 'cygwin' else filename
 
 
-def _normalize_cached(filename, _cache={}):
-    try:
-        return _cache[filename]
-    except KeyError:
-        _cache[filename] = result = normalize_path(filename)
-        return result
+@functools.lru_cache(maxsize=None)
+def _normalize_cached(filename):
+    return normalize_path(filename)
 
 
 def _is_egg_path(path):

pkg_resources/tests/test_pkg_resources.py

@@ -344,7 +344,9 @@ def fake_open(file, *args, **kwargs):
 
     # Ensure that the _macos_vers works correctly
     with mock.patch('builtins.open', mock.Mock(side_effect=fake_open)) as m:
-        assert pkg_resources._macos_vers([]) == ["11", "4"]
+        pkg_resources._macos_vers.cache_clear()
+        assert pkg_resources._macos_vers() == ["11", "4"]
+        pkg_resources._macos_vers.cache_clear()
 
     m.assert_called()
 

setuptools/build_meta.py

@@ -121,7 +121,7 @@ def _file_with_extension(directory, extension):
         raise ValueError(
             'No distribution was found. Ensure that `setup.py` '
             'is not empty and that it calls `setup()`.'
-        )
+        ) from None
     return file
 
 

setuptools/command/build_ext.py

@@ -157,7 +157,7 @@ def get_ext_filename(self, fullname):
 
         if fullname in self.ext_map:
             ext = self.ext_map[fullname]
-            use_abi3 = getattr(ext, 'py_limited_api') and get_abi3_suffix()
+            use_abi3 = ext.py_limited_api and get_abi3_suffix()
             if use_abi3:
                 filename = filename[: -len(so_ext)]
                 so_ext = get_abi3_suffix()

setuptools/command/build_py.py

@@ -288,7 +288,7 @@ def exclude_data_files(self, package, src_dir, files):
         return list(unique_everseen(keepers))
 
     @staticmethod
-    def _get_platform_patterns(spec, package, src_dir, extra_patterns=[]):
+    def _get_platform_patterns(spec, package, src_dir, extra_patterns=()):
         """
         yield platform-specific path patterns (suitable for glob
         or fn_match) from a glob-based spec (such as

setuptools/command/editable_wheel.py

@@ -19,7 +19,7 @@
 from contextlib import suppress
 from enum import Enum
 from inspect import cleandoc
-from itertools import chain
+from itertools import chain, starmap
 from pathlib import Path
 from tempfile import TemporaryDirectory
 from typing import (
@@ -606,7 +606,7 @@ def _simple_layout(
     layout = {pkg: find_package_path(pkg, package_dir, project_dir) for pkg in packages}
     if not layout:
         return set(package_dir) in ({}, {""})
-    parent = os.path.commonpath([_parent_path(k, v) for k, v in layout.items()])
+    parent = os.path.commonpath(starmap(_parent_path, layout.items()))
     return all(
         _path.same_path(Path(parent, *key.split('.')), value)
         for key, value in layout.items()

setuptools/command/egg_info.py

@@ -385,9 +385,8 @@ def process_template_line(self, line):
         try:
             process_action = action_map[action]
         except KeyError:
-            raise DistutilsInternalError(
-                "this cannot happen: invalid action '{action!s}'".format(action=action),
-            )
+            msg = f"Invalid MANIFEST.in: unknown action {action!r} in {line!r}"
+            raise DistutilsInternalError(msg) from None
 
         # OK, now we know that the action is valid and we have the
         # right number of words on the line for that action -- so we

setuptools/command/sdist.py

@@ -105,7 +105,7 @@ class NoValue:
             yield
         finally:
             if orig_val is not NoValue:
-                setattr(os, 'link', orig_val)
+                os.link = orig_val
 
     def add_defaults(self):
         super().add_defaults()

setuptools/command/test.py

@@ -132,7 +132,7 @@ def with_project_on_sys_path(self, func):
             func()
 
     @contextlib.contextmanager
-    def project_on_sys_path(self, include_dists=[]):
+    def project_on_sys_path(self, include_dists=()):
         self.run_command('egg_info')
 
         # Build extensions in-place

setuptools/config/_validate_pyproject/error_reporting.py

@@ -24,7 +24,7 @@
     "must not be there",
 )
 
-_NEED_DETAILS = {"anyOf", "oneOf", "anyOf", "contains", "propertyNames", "not", "items"}
+_NEED_DETAILS = {"anyOf", "oneOf", "allOf", "contains", "propertyNames", "not", "items"}
 
 _CAMEL_CASE_SPLITTER = re.compile(r"\W+|([A-Z][^A-Z\W]*)")
 _IDENTIFIER = re.compile(r"^[\w_]+$", re.I)

setuptools/config/setupcfg.py

@@ -283,8 +283,8 @@ def __setitem__(self, option_name, value):
 
         try:
             current_value = getattr(target_obj, option_name)
-        except AttributeError:
-            raise KeyError(option_name)
+        except AttributeError as e:
+            raise KeyError(option_name) from e
 
         if current_value:
             # Already inhabited. Skipping.
@@ -582,11 +582,11 @@ def _parse_version(self, value):
             # accidentally include newlines and other unintended content
             try:
                 Version(version)
-            except InvalidVersion:
+            except InvalidVersion as e:
                 raise OptionError(
                     f'Version loaded from {value} does not '
                     f'comply with PEP 440: {version}'
-                )
+                ) from e
 
             return version
 

setuptools/monkey.py

@@ -130,7 +130,7 @@ def patch_func(replacement, target_mod, func_name):
 
 
 def get_unpatched_function(candidate):
-    return getattr(candidate, 'unpatched')
+    return candidate.unpatched
 
 
 def patch_for_msvc_specialized_compiler():

setuptools/tests/config/test_setupcfg.py

@@ -957,17 +957,13 @@ class TestExternalSetters:
     # pbr or something else setting these values.
     def _fake_distribution_init(self, dist, attrs):
         saved_dist_init(dist, attrs)
-        # see self._DISTUTUILS_UNSUPPORTED_METADATA
-        setattr(dist.metadata, 'long_description_content_type', 'text/something')
+        # see self._DISTUTILS_UNSUPPORTED_METADATA
+        dist.metadata.long_description_content_type = 'text/something'
         # Test overwrite setup() args
-        setattr(
-            dist.metadata,
-            'project_urls',
-            {
-                'Link One': 'https://example.com/one/',
-                'Link Two': 'https://example.com/two/',
-            },
-        )
+        dist.metadata.project_urls = {
+            'Link One': 'https://example.com/one/',
+            'Link Two': 'https://example.com/two/',
+        }
         return None
 
     @patch.object(_Distribution, '__init__', autospec=True)

setuptools/tests/test_build_meta.py

@@ -30,9 +30,9 @@
 
 
 class BuildBackendBase:
-    def __init__(self, cwd='.', env={}, backend_name='setuptools.build_meta'):
+    def __init__(self, cwd='.', env=None, backend_name='setuptools.build_meta'):
         self.cwd = cwd
-        self.env = env
+        self.env = env or {}
         self.backend_name = backend_name
 
 

setuptools/tests/test_easy_install.py

@@ -1195,7 +1195,7 @@ def create_setup_requires_package(
     version='0.1',
     make_package=make_trivial_sdist,
     setup_py_template=None,
-    setup_attrs={},
+    setup_attrs=None,
     use_setup_cfg=(),
 ):
     """Creates a source tree under path for a trivial test package that has a
@@ -1213,7 +1213,8 @@ def create_setup_requires_package(
         'setup_requires': ['%s==%s' % (distname, version)],
         'dependency_links': [os.path.abspath(path)],
     }
-    test_setup_attrs.update(setup_attrs)
+    if setup_attrs:
+        test_setup_attrs.update(setup_attrs)
 
     test_pkg = os.path.join(path, 'test_pkg')
     os.mkdir(test_pkg)

setuptools/tests/test_msvc14.py

@@ -57,7 +57,7 @@ def test_get_vc2017(self):
         # This function cannot be mocked, so pass it if we find VS 2017
         # and mark it skipped if we do not.
         version, path = _msvccompiler._msvc14_find_vc2017()
-        if os.environ.get('APPVEYOR_BUILD_WORKER_IMAGE', '') in ['Visual Studio 2017']:
+        if os.environ.get('APPVEYOR_BUILD_WORKER_IMAGE', '') == 'Visual Studio 2017':
             assert version
         if version:
             assert version >= 15

setuptools/tests/test_sdist.py

@@ -658,7 +658,7 @@ def test_sdist_with_latin1_encoded_filename(self):
         else:
             # The Latin-1 filename should have been skipped
             filename = filename.decode('latin-1')
-            filename not in cmd.filelist.files
+            assert filename not in cmd.filelist.files
 
     _EXAMPLE_DIRECTIVES = {
         "setup.cfg - long_description and version": """

setuptools/tests/test_setuptools.py

@@ -61,13 +61,13 @@ def f1():
         assert dep.extract_constant(fc, 'q', -1) is None
 
         # constant assigned
-        dep.extract_constant(fc, 'x', -1) == "test"
+        assert dep.extract_constant(fc, 'x', -1) == "test"
 
         # expression assigned
-        dep.extract_constant(fc, 'y', -1) == -1
+        assert dep.extract_constant(fc, 'y', -1) == -1
 
         # recognized name, not assigned
-        dep.extract_constant(fc, 'z', -1) is None
+        assert dep.extract_constant(fc, 'z', -1) is None
 
     def testFindModule(self):
         with pytest.raises(ImportError):

tools/build_launchers.py

@@ -118,8 +118,8 @@ def get_msbuild():
     ]
     try:
         return subprocess.check_output(cmd, encoding='utf-8', text=True).strip()
-    except subprocess.CalledProcessError:
-        raise SystemExit("Unable to find MSBuild; check Visual Studio install")
+    except subprocess.CalledProcessError as e:
+        raise SystemExit("Unable to find MSBuild; check Visual Studio install") from e
 
 
 def do_build(arena, platform, target):