Merge pull request #2518 from webknjaz/maintenance/flake8-mccabe-complexity

Enable McCabe complexity check in flake8

.flake8

@@ -12,3 +12,6 @@ ignore =
 	E203
 	setuptools/site-patch.py F821
 	setuptools/py*compat.py F811
+
+# Let's not overcomplicate the code:
+max-complexity = 10

pkg_resources/__init__.py

@@ -697,7 +697,8 @@ class WorkingSet:
             keys2.append(dist.key)
         self._added_new(dist)
 
-    def resolve(self, requirements, env=None, installer=None,
+    # FIXME: 'WorkingSet.resolve' is too complex (11)
+    def resolve(self, requirements, env=None, installer=None,  # noqa: C901
                 replace_conflicting=False, extras=None):
         """List all distributions needed to (recursively) meet `requirements`
 
@@ -1746,7 +1747,8 @@ class ZipProvider(EggProvider):
         timestamp = time.mktime(date_time)
         return timestamp, size
 
-    def _extract_resource(self, manager, zip_path):
+    # FIXME: 'ZipProvider._extract_resource' is too complex (12)
+    def _extract_resource(self, manager, zip_path):  # noqa: C901
 
         if zip_path in self._index():
             for name in self._index()[zip_path]:
@@ -2859,7 +2861,8 @@ class Distribution:
         """Return the EntryPoint object for `group`+`name`, or ``None``"""
         return self.get_entry_map(group).get(name)
 
-    def insert_on(self, path, loc=None, replace=False):
+    # FIXME: 'Distribution.insert_on' is too complex (13)
+    def insert_on(self, path, loc=None, replace=False):  # noqa: C901
         """Ensure self.location is on path
 
         If replace=False (default):

setuptools/archive_util.py

@@ -125,6 +125,56 @@ def unpack_zipfile(filename, extract_dir, progress_filter=default_filter):
                 os.chmod(target, unix_attributes)
 
 
+def _resolve_tar_file_or_dir(tar_obj, tar_member_obj):
+    """Resolve any links and extract link targets as normal files."""
+    while tar_member_obj is not None and (
+            tar_member_obj.islnk() or tar_member_obj.issym()):
+        linkpath = tar_member_obj.linkname
+        if tar_member_obj.issym():
+            base = posixpath.dirname(tar_member_obj.name)
+            linkpath = posixpath.join(base, linkpath)
+            linkpath = posixpath.normpath(linkpath)
+        tar_member_obj = tar_obj._getmember(linkpath)
+
+    is_file_or_dir = (
+        tar_member_obj is not None and
+        (tar_member_obj.isfile() or tar_member_obj.isdir())
+    )
+    if is_file_or_dir:
+        return tar_member_obj
+
+    raise LookupError('Got unknown file type')
+
+
+def _iter_open_tar(tar_obj, extract_dir, progress_filter):
+    """Emit member-destination pairs from a tar archive."""
+    # don't do any chowning!
+    tar_obj.chown = lambda *args: None
+
+    with contextlib.closing(tar_obj):
+        for member in tar_obj:
+            name = member.name
+            # don't extract absolute paths or ones with .. in them
+            if name.startswith('/') or '..' in name.split('/'):
+                continue
+
+            prelim_dst = os.path.join(extract_dir, *name.split('/'))
+
+            try:
+                member = _resolve_tar_file_or_dir(tar_obj, member)
+            except LookupError:
+                continue
+
+            final_dst = progress_filter(name, prelim_dst)
+            if not final_dst:
+                continue
+
+            if final_dst.endswith(os.sep):
+                final_dst = final_dst[:-1]
+
+            yield member, final_dst
+
+
 def unpack_tarfile(filename, extract_dir, progress_filter=default_filter):
     """Unpack tar/tar.gz/tar.bz2 `filename` to `extract_dir`
 
@@ -138,37 +188,17 @@ def unpack_tarfile(filename, extract_dir, progress_filter=default_filter):
         raise UnrecognizedFormat(
             "%s is not a compressed or uncompressed tar file" % (filename,)
         ) from e
-    with contextlib.closing(tarobj):
-        # don't do any chowning!
-        tarobj.chown = lambda *args: None
-        for member in tarobj:
-            name = member.name
-            # don't extract absolute paths or ones with .. in them
-            if not name.startswith('/') and '..' not in name.split('/'):
-                prelim_dst = os.path.join(extract_dir, *name.split('/'))
-
-                # resolve any links and to extract the link targets as normal
-                # files
-                while member is not None and (
-                        member.islnk() or member.issym()):
-                    linkpath = member.linkname
-                    if member.issym():
-                        base = posixpath.dirname(member.name)
-                        linkpath = posixpath.join(base, linkpath)
-                        linkpath = posixpath.normpath(linkpath)
-                    member = tarobj._getmember(linkpath)
 
-                if member is not None and (member.isfile() or member.isdir()):
-                    final_dst = progress_filter(name, prelim_dst)
-                    if final_dst:
-                        if final_dst.endswith(os.sep):
-                            final_dst = final_dst[:-1]
+    for member, final_dst in _iter_open_tar(
+            tarobj, extract_dir, progress_filter,
+    ):
         try:
             # XXX Ugh
             tarobj._extract_member(member, final_dst)
         except tarfile.ExtractError:
             # chown/chmod/mkfifo/mknode/makedev failed
             pass
+
     return True
 
 

setuptools/command/bdist_egg.py

@@ -153,7 +153,7 @@ class bdist_egg(Command):
         self.run_command(cmdname)
         return cmd
 
-    def run(self):
+    def run(self):  # noqa: C901  # is too complex (14)  # FIXME
         # Generate metadata first
         self.run_command("egg_info")
         # We run install_lib before install_data, because some data hacks

setuptools/command/easy_install.py

@@ -226,7 +226,7 @@ class easy_install(Command):
         print(tmpl.format(**locals()))
         raise SystemExit()
 
-    def finalize_options(self):
+    def finalize_options(self):  # noqa: C901  # is too complex (25)  # FIXME
         self.version and self._render_version()
 
         py_version = sys.version.split()[0]
@@ -437,7 +437,7 @@ class easy_install(Command):
     def warn_deprecated_options(self):
         pass
 
-    def check_site_dir(self):
+    def check_site_dir(self):  # noqa: C901  # is too complex (12)  # FIXME
         """Verify that self.install_dir is .pth-capable dir, if needed"""
 
         instdir = normalize_path(self.install_dir)
@@ -713,7 +713,10 @@ class easy_install(Command):
             if getattr(self, attrname) is None:
                 setattr(self, attrname, scheme[key])
 
-    def process_distribution(self, requirement, dist, deps=True, *info):
+    # FIXME: 'easy_install.process_distribution' is too complex (12)
+    def process_distribution(  # noqa: C901
+            self, requirement, dist, deps=True, *info,
+    ):
         self.update_pth(dist)
         self.package_index.add(dist)
         if dist in self.local_index[dist.key]:
@@ -837,12 +840,19 @@ class easy_install(Command):
 
     def install_eggs(self, spec, dist_filename, tmpdir):
         # .egg dirs or files are already built, so just return them
-        if dist_filename.lower().endswith('.egg'):
-            return [self.install_egg(dist_filename, tmpdir)]
-        elif dist_filename.lower().endswith('.exe'):
-            return [self.install_exe(dist_filename, tmpdir)]
-        elif dist_filename.lower().endswith('.whl'):
-            return [self.install_wheel(dist_filename, tmpdir)]
+        installer_map = {
+            '.egg': self.install_egg,
+            '.exe': self.install_exe,
+            '.whl': self.install_wheel,
+        }
+        try:
+            install_dist = installer_map[
+                dist_filename.lower()[-4:]
+            ]
+        except KeyError:
+            pass
+        else:
+            return [install_dist(dist_filename, tmpdir)]
 
         # Anything else, try to extract and build
         setup_base = tmpdir
@@ -887,7 +897,8 @@ class easy_install(Command):
             metadata = EggMetadata(zipimport.zipimporter(egg_path))
         return Distribution.from_filename(egg_path, metadata=metadata)
 
-    def install_egg(self, egg_path, tmpdir):
+    # FIXME: 'easy_install.install_egg' is too complex (11)
+    def install_egg(self, egg_path, tmpdir):  # noqa: C901
         destination = os.path.join(
             self.install_dir,
             os.path.basename(egg_path),
@@ -986,7 +997,8 @@ class easy_install(Command):
         # install the .egg
         return self.install_egg(egg_path, tmpdir)
 
-    def exe_to_egg(self, dist_filename, egg_tmp):
+    # FIXME: 'easy_install.exe_to_egg' is too complex (12)
+    def exe_to_egg(self, dist_filename, egg_tmp):  # noqa: C901
         """Extract a bdist_wininst to the directories an egg would use"""
         # Check for .pth file and set up prefix translations
         prefixes = get_exe_prefixes(dist_filename)
@@ -1184,12 +1196,14 @@ class easy_install(Command):
         cfg_filename = os.path.join(base, 'setup.cfg')
         setopt.edit_config(cfg_filename, settings)
 
-    def update_pth(self, dist):
+    def update_pth(self, dist):  # noqa: C901  # is too complex (11)  # FIXME
         if self.pth_file is None:
             return
 
         for d in self.pth_file[dist.key]:  # drop old entries
-            if self.multi_version or d.location != dist.location:
+            if not self.multi_version and d.location == dist.location:
+                continue
+
             log.info("Removing %s from easy-install.pth file", d)
             self.pth_file.remove(d)
             if d.location in self.shadow_path:
@@ -1207,19 +1221,21 @@ class easy_install(Command):
                 if dist.location not in self.shadow_path:
                     self.shadow_path.append(dist.location)
 
-        if not self.dry_run:
+        if self.dry_run:
+            return
 
         self.pth_file.save()
 
-            if dist.key == 'setuptools':
+        if dist.key != 'setuptools':
+            return
+
         # Ensure that setuptools itself never becomes unavailable!
         # XXX should this check for latest version?
         filename = os.path.join(self.install_dir, 'setuptools.pth')
         if os.path.islink(filename):
             os.unlink(filename)
-                f = open(filename, 'wt')
+        with open(filename, 'wt') as f:
             f.write(self.pth_file.make_relative(dist.location) + '\n')
-                f.close()
 
     def unpack_progress(self, src, dst):
         # Progress filter for unpacking
@@ -1360,7 +1376,9 @@ def get_site_dirs():
     if sys.exec_prefix != sys.prefix:
         prefixes.append(sys.exec_prefix)
     for prefix in prefixes:
-        if prefix:
+        if not prefix:
+            continue
+
         if sys.platform in ('os2emx', 'riscos'):
             sitedirs.append(os.path.join(prefix, "Lib", "site-packages"))
         elif os.sep == '/':
@@ -1378,13 +1396,19 @@ def get_site_dirs():
                 prefix,
                 os.path.join(prefix, "lib", "site-packages"),
             ])
-            if sys.platform == 'darwin':
+        if sys.platform != 'darwin':
+            continue
+
         # for framework builds *only* we add the standard Apple
         # locations. Currently only per-user, but /Library and
         # /Network/Library could be added too
-                if 'Python.framework' in prefix:
+        if 'Python.framework' not in prefix:
+            continue
+
         home = os.environ.get('HOME')
-                    if home:
+        if not home:
+            continue
+
         home_sp = os.path.join(
             home,
             'Library',
@@ -1394,24 +1418,21 @@ def get_site_dirs():
         )
         sitedirs.append(home_sp)
     lib_paths = get_path('purelib'), get_path('platlib')
-    for site_lib in lib_paths:
-        if site_lib not in sitedirs:
-            sitedirs.append(site_lib)
+
+    sitedirs.extend(s for s in lib_paths if s not in sitedirs)
 
     if site.ENABLE_USER_SITE:
         sitedirs.append(site.USER_SITE)
 
-    try:
+    with contextlib.suppress(AttributeError):
         sitedirs.extend(site.getsitepackages())
-    except AttributeError:
-        pass
 
     sitedirs = list(map(normalize_path, sitedirs))
 
     return sitedirs
 
 
-def expand_paths(inputs):
+def expand_paths(inputs):  # noqa: C901  # is too complex (11)  # FIXME
     """Yield sys.path directories that might contain "old-style" packages"""
 
     seen = {}
@@ -1443,12 +1464,17 @@ def expand_paths(inputs):
 
             # Yield existing non-dupe, non-import directory lines from it
             for line in lines:
-                if not line.startswith("import"):
+                if line.startswith("import"):
+                    continue
+
                 line = normalize_path(line.rstrip())
-                    if line not in seen:
+                if line in seen:
+                    continue
+
                 seen[line] = 1
                 if not os.path.isdir(line):
                     continue
+
                 yield line, os.listdir(line)
 
 

setuptools/command/egg_info.py

@@ -8,6 +8,7 @@ from distutils.util import convert_path
 from distutils import log
 import distutils.errors
 import distutils.filelist
+import functools
 import os
 import re
 import sys
@@ -31,7 +32,7 @@ from setuptools.extern import packaging
 from setuptools import SetuptoolsDeprecationWarning
 
 
-def translate_pattern(glob):
+def translate_pattern(glob):  # noqa: C901  # is too complex (14)  # FIXME
     """
     Translate a file path glob like '*.txt' in to a regular expression.
     This differs from fnmatch.translate which allows wildcards to match
@@ -334,70 +335,74 @@ class FileList(_FileList):
         # patterns, (dir and patterns), or (dir_pattern).
         (action, patterns, dir, dir_pattern) = self._parse_template_line(line)
 
+        action_map = {
+            'include': self.include,
+            'exclude': self.exclude,
+            'global-include': self.global_include,
+            'global-exclude': self.global_exclude,
+            'recursive-include': functools.partial(
+                self.recursive_include, dir,
+            ),
+            'recursive-exclude': functools.partial(
+                self.recursive_exclude, dir,
+            ),
+            'graft': self.graft,
+            'prune': self.prune,
+        }
+        log_map = {
+            'include': "warning: no files found matching '%s'",
+            'exclude': (
+                "warning: no previously-included files found "
+                "matching '%s'"
+            ),
+            'global-include': (
+                "warning: no files found matching '%s' "
+                "anywhere in distribution"
+            ),
+            'global-exclude': (
+                "warning: no previously-included files matching "
+                "'%s' found anywhere in distribution"
+            ),
+            'recursive-include': (
+                "warning: no files found matching '%s' "
+                "under directory '%s'"
+            ),
+            'recursive-exclude': (
+                "warning: no previously-included files matching "
+                "'%s' found under directory '%s'"
+            ),
+            'graft': "warning: no directories found matching '%s'",
+            'prune': "no previously-included directories found matching '%s'",
+        }
+
+        try:
+            process_action = action_map[action]
+        except KeyError:
+            raise DistutilsInternalError(
+                "this cannot happen: invalid action '{action!s}'".
+                format(action=action),
+            )
+
         # 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
         # can proceed with minimal error-checking.
-        if action == 'include':
-            self.debug_print("include " + ' '.join(patterns))
-            for pattern in patterns:
-                if not self.include(pattern):
-                    log.warn("warning: no files found matching '%s'", pattern)
-
-        elif action == 'exclude':
-            self.debug_print("exclude " + ' '.join(patterns))
-            for pattern in patterns:
-                if not self.exclude(pattern):
-                    log.warn(("warning: no previously-included files "
-                              "found matching '%s'"), pattern)
 
-        elif action == 'global-include':
-            self.debug_print("global-include " + ' '.join(patterns))
-            for pattern in patterns:
-                if not self.global_include(pattern):
-                    log.warn(("warning: no files found matching '%s' "
-                              "anywhere in distribution"), pattern)
-
-        elif action == 'global-exclude':
-            self.debug_print("global-exclude " + ' '.join(patterns))
-            for pattern in patterns:
-                if not self.global_exclude(pattern):
-                    log.warn(("warning: no previously-included files matching "
-                              "'%s' found anywhere in distribution"),
-                             pattern)
-
-        elif action == 'recursive-include':
-            self.debug_print("recursive-include %s %s" %
-                             (dir, ' '.join(patterns)))
-            for pattern in patterns:
-                if not self.recursive_include(dir, pattern):
-                    log.warn(("warning: no files found matching '%s' "
-                              "under directory '%s'"),
-                             pattern, dir)
-
-        elif action == 'recursive-exclude':
-            self.debug_print("recursive-exclude %s %s" %
-                             (dir, ' '.join(patterns)))
+        action_is_recursive = action.startswith('recursive-')
+        if action in {'graft', 'prune'}:
+            patterns = [dir_pattern]
+        extra_log_args = (dir, ) if action_is_recursive else ()
+        log_tmpl = log_map[action]
+
+        self.debug_print(
+            ' '.join(
+                [action] +
+                ([dir] if action_is_recursive else []) +
+                patterns,
+            )
+        )
         for pattern in patterns:
-                if not self.recursive_exclude(dir, pattern):
-                    log.warn(("warning: no previously-included files matching "
-                              "'%s' found under directory '%s'"),
-                             pattern, dir)
-
-        elif action == 'graft':
-            self.debug_print("graft " + dir_pattern)
-            if not self.graft(dir_pattern):
-                log.warn("warning: no directories found matching '%s'",
-                         dir_pattern)
-
-        elif action == 'prune':
-            self.debug_print("prune " + dir_pattern)
-            if not self.prune(dir_pattern):
-                log.warn(("no previously-included directories found "
-                          "matching '%s'"), dir_pattern)
-
-        else:
-            raise DistutilsInternalError(
-                "this cannot happen: invalid action '%s'" % action)
+            if not process_action(pattern):
+                log.warn(log_tmpl, pattern, *extra_log_args)
 
     def _remove_files(self, predicate):
         """

setuptools/dist.py

@@ -119,7 +119,7 @@ def read_pkg_file(self, file):
 
 
 # Based on Python 3.5 version
-def write_pkg_file(self, file):
+def write_pkg_file(self, file):  # noqa: C901  # is too complex (14)  # FIXME
     """Write the PKG-INFO format data to a file object.
     """
     version = self.get_metadata_version()
@@ -548,7 +548,8 @@ class Distribution(_Distribution):
         req.marker = None
         return req
 
-    def _parse_config_files(self, filenames=None):
+    # FIXME: 'Distribution._parse_config_files' is too complex (14)
+    def _parse_config_files(self, filenames=None):  # noqa: C901
         """
         Adapted from distutils.dist.Distribution.parse_config_files,
         this method provides the same functionality in subtly-improved
@@ -557,14 +558,12 @@ class Distribution(_Distribution):
         from configparser import ConfigParser
 
         # Ignore install directory options if we have a venv
-        if sys.prefix != sys.base_prefix:
-            ignore_options = [
+        ignore_options = [] if sys.prefix == sys.base_prefix else [
             'install-base', 'install-platbase', 'install-lib',
             'install-platlib', 'install-purelib', 'install-headers',
             'install-scripts', 'install-data', 'prefix', 'exec-prefix',
-                'home', 'user', 'root']
-        else:
-            ignore_options = []
+            'home', 'user', 'root',
+        ]
 
         ignore_options = frozenset(ignore_options)
 
@@ -585,7 +584,9 @@ class Distribution(_Distribution):
                 opt_dict = self.get_option_dict(section)
 
                 for opt in options:
-                    if opt != '__name__' and opt not in ignore_options:
+                    if opt == '__name__' or opt in ignore_options:
+                        continue
+
                     val = parser.get(section, opt)
                     opt = opt.replace('-', '_')
                     opt_dict[opt] = (filename, val)
@@ -594,23 +595,26 @@ class Distribution(_Distribution):
             # the original filenames that options come from)
             parser.__init__()
 
+        if 'global' not in self.command_options:
+            return
+
         # If there was a "global" section in the config file, use it
         # to set Distribution options.
 
-        if 'global' in self.command_options:
         for (opt, (src, val)) in self.command_options['global'].items():
             alias = self.negative_opt.get(opt)
-                try:
             if alias:
-                        setattr(self, alias, not strtobool(val))
+                val = not strtobool(val)
             elif opt in ('verbose', 'dry_run'):  # ugh!
-                        setattr(self, opt, strtobool(val))
-                    else:
-                        setattr(self, opt, val)
+                val = strtobool(val)
+
+            try:
+                setattr(self, alias or opt, val)
             except ValueError as e:
                 raise DistutilsOptionError(e) from e
 
-    def _set_command_options(self, command_obj, option_dict=None):
+    # FIXME: 'Distribution._set_command_options' is too complex (14)
+    def _set_command_options(self, command_obj, option_dict=None):  # noqa: C901
         """
         Set the options for 'command_obj' from 'option_dict'.  Basically
         this means copying elements of a dictionary ('option_dict') to

setuptools/glob.py

@@ -47,6 +47,8 @@ def iglob(pathname, recursive=False):
 
 def _iglob(pathname, recursive):
     dirname, basename = os.path.split(pathname)
+    glob_in_dir = glob2 if recursive and _isrecursive(basename) else glob1
+
     if not has_magic(pathname):
         if basename:
             if os.path.lexists(pathname):
@@ -56,13 +58,9 @@ def _iglob(pathname, recursive):
             if os.path.isdir(dirname):
                 yield pathname
         return
+
     if not dirname:
-        if recursive and _isrecursive(basename):
-            for x in glob2(dirname, basename):
-                yield x
-        else:
-            for x in glob1(dirname, basename):
-                yield x
+        yield from glob_in_dir(dirname, basename)
         return
     # `os.path.split()` returns the argument itself as a dirname if it is a
     # drive or UNC path.  Prevent an infinite recursion if a drive or UNC path
@@ -71,12 +69,7 @@ def _iglob(pathname, recursive):
         dirs = _iglob(dirname, recursive)
     else:
         dirs = [dirname]
-    if has_magic(basename):
-        if recursive and _isrecursive(basename):
-            glob_in_dir = glob2
-        else:
-            glob_in_dir = glob1
-    else:
+    if not has_magic(basename):
         glob_in_dir = glob0
     for dirname in dirs:
         for name in glob_in_dir(dirname, basename):

setuptools/installer.py

@@ -51,7 +51,7 @@ def _legacy_fetch_build_egg(dist, req):
     return cmd.easy_install(req)
 
 
-def fetch_build_egg(dist, req):
+def fetch_build_egg(dist, req):  # noqa: C901  # is too complex (16)  # FIXME
     """Fetch an egg needed for building.
 
     Use pip/wheel to fetch/build a wheel."""
@@ -80,20 +80,17 @@ def fetch_build_egg(dist, req):
     if 'allow_hosts' in opts:
         raise DistutilsError('the `allow-hosts` option is not supported '
                              'when using pip to install requirements.')
-    if 'PIP_QUIET' in os.environ or 'PIP_VERBOSE' in os.environ:
-        quiet = False
-    else:
-        quiet = True
+    quiet = 'PIP_QUIET' not in os.environ and 'PIP_VERBOSE' not in os.environ
     if 'PIP_INDEX_URL' in os.environ:
         index_url = None
     elif 'index_url' in opts:
         index_url = opts['index_url'][1]
     else:
         index_url = None
-    if 'find_links' in opts:
-        find_links = _fixup_find_links(opts['find_links'][1])[:]
-    else:
-        find_links = []
+    find_links = (
+        _fixup_find_links(opts['find_links'][1])[:] if 'find_links' in opts
+        else []
+    )
     if dist.dependency_links:
         find_links.extend(dist.dependency_links)
     eggs_dir = os.path.realpath(dist.get_egg_cache_dir())
@@ -112,16 +109,12 @@ def fetch_build_egg(dist, req):
             cmd.append('--quiet')
         if index_url is not None:
             cmd.extend(('--index-url', index_url))
-        if find_links is not None:
-            for link in find_links:
+        for link in find_links or []:
             cmd.extend(('--find-links', link))
         # If requirement is a PEP 508 direct URL, directly pass
         # the URL to pip, as `req @ url` does not work on the
         # command line.
-        if req.url:
-            cmd.append(req.url)
-        else:
-            cmd.append(str(req))
+        cmd.append(req.url or str(req))
         try:
             subprocess.check_call(cmd)
         except subprocess.CalledProcessError as e:

setuptools/msvc.py

@@ -24,6 +24,7 @@ from io import open
 from os import listdir, pathsep
 from os.path import join, isfile, isdir, dirname
 import sys
+import contextlib
 import platform
 import itertools
 import subprocess
@@ -724,8 +725,7 @@ class SystemInfo:
         ms = self.ri.microsoft
         vckeys = (self.ri.vc, self.ri.vc_for_python, self.ri.vs)
         vs_vers = []
-        for hkey in self.ri.HKEYS:
-            for key in vckeys:
+        for hkey, key in itertools.product(self.ri.HKEYS, vckeys):
             try:
                 bkey = winreg.OpenKey(hkey, ms(key), 0, winreg.KEY_READ)
             except (OSError, IOError):
@@ -733,19 +733,15 @@ class SystemInfo:
             with bkey:
                 subkeys, values, _ = winreg.QueryInfoKey(bkey)
                 for i in range(values):
-                        try:
+                    with contextlib.suppress(ValueError):
                         ver = float(winreg.EnumValue(bkey, i)[0])
                         if ver not in vs_vers:
                             vs_vers.append(ver)
-                        except ValueError:
-                            pass
                 for i in range(subkeys):
-                        try:
+                    with contextlib.suppress(ValueError):
                         ver = float(winreg.EnumKey(bkey, i))
                         if ver not in vs_vers:
                             vs_vers.append(ver)
-                        except ValueError:
-                            pass
         return sorted(vs_vers)
 
     def find_programdata_vs_vers(self):
@@ -925,8 +921,8 @@ class SystemInfo:
         """
         return self._use_last_dir_name(join(self.WindowsSdkDir, 'lib'))
 
-    @property
-    def WindowsSdkDir(self):
+    @property  # noqa: C901
+    def WindowsSdkDir(self):  # noqa: C901  # is too complex (12)  # FIXME
         """
         Microsoft Windows SDK directory.
 

setuptools/package_index.py

@@ -320,7 +320,8 @@ class PackageIndex(Environment):
         else:
             self.opener = urllib.request.urlopen
 
-    def process_url(self, url, retrieve=False):
+    # FIXME: 'PackageIndex.process_url' is too complex (14)
+    def process_url(self, url, retrieve=False):  # noqa: C901
         """Evaluate a URL as a possible download, and maybe retrieve it"""
         if url in self.scanned_urls and not retrieve:
             return
@@ -428,32 +429,38 @@ class PackageIndex(Environment):
             dist.precedence = SOURCE_DIST
             self.add(dist)
 
-    def process_index(self, url, page):
-        """Process the contents of a PyPI page"""
-
-        def scan(link):
+    def _scan(self, link):
         # Process a URL to see if it's for a package page
-            if link.startswith(self.index_url):
+        NO_MATCH_SENTINEL = None, None
+        if not link.startswith(self.index_url):
+            return NO_MATCH_SENTINEL
+
         parts = list(map(
             urllib.parse.unquote, link[len(self.index_url):].split('/')
         ))
-                if len(parts) == 2 and '#' not in parts[1]:
+        if len(parts) != 2 or '#' in parts[1]:
+            return NO_MATCH_SENTINEL
+
         # it's a package page, sanitize and index it
         pkg = safe_name(parts[0])
         ver = safe_version(parts[1])
         self.package_pages.setdefault(pkg.lower(), {})[link] = True
         return to_filename(pkg), to_filename(ver)
-            return None, None
+
+    def process_index(self, url, page):
+        """Process the contents of a PyPI page"""
 
         # process an index page into the package-page index
         for match in HREF.finditer(page):
             try:
-                scan(urllib.parse.urljoin(url, htmldecode(match.group(1))))
+                self._scan(urllib.parse.urljoin(url, htmldecode(match.group(1))))
             except ValueError:
                 pass
 
-        pkg, ver = scan(url)  # ensure this page is in the page index
-        if pkg:
+        pkg, ver = self._scan(url)  # ensure this page is in the page index
+        if not pkg:
+            return ""  # no sense double-scanning non-package pages
+
         # process individual package page
         for new_url in find_external_links(url, page):
             # Process the found URL
@@ -468,8 +475,6 @@ class PackageIndex(Environment):
         return PYPI_MD5.sub(
             lambda m: '<a href="%s#md5=%s">%s</a>' % m.group(1, 3, 2), page
         )
-        else:
-            return ""  # no sense double-scanning non-package pages
 
     def need_version_info(self, url):
         self.scan_all(
@@ -591,7 +596,7 @@ class PackageIndex(Environment):
                 spec = parse_requirement_arg(spec)
         return getattr(self.fetch_distribution(spec, tmpdir), 'location', None)
 
-    def fetch_distribution(
+    def fetch_distribution(  # noqa: C901  # is too complex (14)  # FIXME
             self, requirement, tmpdir, force_scan=False, source=False,
             develop_ok=False, local_index=None):
         """Obtain a distribution suitable for fulfilling `requirement`
@@ -762,7 +767,8 @@ class PackageIndex(Environment):
     def reporthook(self, url, filename, blocknum, blksize, size):
         pass  # no-op
 
-    def open_url(self, url, warning=None):
+    # FIXME:
+    def open_url(self, url, warning=None):  # noqa: C901  # is too complex (12)
         if url.startswith('file:'):
             return local_open(url)
         try:

setuptools/ssl_support.py

@@ -56,7 +56,7 @@ if not CertificateError:
         pass
 
 
-if not match_hostname:
+if not match_hostname:  # noqa: C901  # 'If 59' is too complex (21)  # FIXME
 
     def _dnsname_match(dn, hostname, max_wildcards=1):
         """Matching according to RFC 6125, section 6.4.3