[Python] Update linter rules

In swiftlang/swift@d5326bf,
@practicalswift updated the Swift project to no longer ignore
individual linter rules globally. Update the SwiftPM project to do the
same.

In addition, fix all remaining linter rule violations. Most of these
involved splitting up lines. One spot involved using `endswith()` with
a tuple argument to check against multiple suffixes at once.

To lint the Python code in the project:

    $ flake8

To install flake8:

    $ pip install flake8

See https://flake8.readthedocs.org/en/latest/ for details.

Author: modocache

.pep8

@@ -1,3 +1,3 @@
 [flake8]
 filename = *.py,bootstrap
-ignore = E101,E111,E128,E265,E302,E402,E501,W191
+max-line-length = 80

Utilities/bootstrap

@@ -42,17 +42,18 @@ import subprocess
 import sys
 import tempfile
 
-###
 
 def note(message):
     print("%s: note: %s" % (os.path.basename(sys.argv[0]), message))
     sys.stdout.flush()
 
+
 def error(message):
     print("%s: error: %s" % (os.path.basename(sys.argv[0]), message))
     sys.stdout.flush()
     raise SystemExit(1)
 
+
 def mkdir_p(path):
     """
     mkdir_p(path)
@@ -67,6 +68,7 @@ def mkdir_p(path):
         if e.errno != errno.EEXIST:
             raise
 
+
 # FIXME: Consider eliminating this once the build task format supports node
 # hashing.
 def write_file_if_changed(path, data):
@@ -94,9 +96,12 @@ g_num_cpus = os.sysconf("SC_NPROCESSORS_ONLN")
 g_default_sysroot = None
 if platform.system() == 'Darwin':
     g_platform_path = subprocess.check_output(
-        ["xcrun", "--sdk", "macosx", "--show-sdk-platform-path"], universal_newlines=True).strip()
+        ["xcrun", "--sdk", "macosx", "--show-sdk-platform-path"],
+        universal_newlines=True).strip()
     g_default_sysroot = subprocess.check_output(
-        ["xcrun", "--sdk", "macosx", "--show-sdk-path"], universal_newlines=True).strip()
+        ["xcrun", "--sdk", "macosx", "--show-sdk-path"],
+        universal_newlines=True).strip()
+
 
 class Target(object):
     @property
@@ -168,22 +173,27 @@ class Target(object):
         print("    outputs: %s" % json.dumps(
             [compile_swift_node, module_path] + swift_objects), file=output)
         print("    module-name: %s" % json.dumps(module_name), file=output)
-        print("    module-output-path: %s" % json.dumps(module_path), file=output)
-        print("    sources: %s" % json.dumps(
-            self.swift_sources), file=output)
+        print("    module-output-path: %s" % json.dumps(module_path),
+              file=output)
+        print("    sources: %s" % json.dumps(self.swift_sources), file=output)
         print("    objects: %s" % json.dumps(swift_objects), file=output)
         print("    import-paths: %s" % json.dumps(
             [module_dir]), file=output)
-        print("    other-args: %s" % json.dumps(' '.join(other_args)), file=output)
+        print("    other-args: %s" % json.dumps(' '.join(other_args)),
+              file=output)
         print("    temps-path: %s" % json.dumps(target_build_dir), file=output)
         print("    is-library: %s" % json.dumps(
             str(bool(self.is_library)).lower()), file=output)
         print(file=output)
 
+
 # currently only returns the targets parsed from the manifest
 def parse_manifest():
-    # we have a *very* strict format for our manifest to make parsing more robust
-    pattern = re.compile(r'Target\(.*?name: "(.*?)",\n *dependencies: (\[.*?\])\)', re.DOTALL|re.MULTILINE)
+    # we have a *very* strict format for our manifest to make parsing more
+    # robust
+    pattern = re.compile(
+        r'Target\(.*?name: "(.*?)",\n *dependencies: (\[.*?\])\)',
+        re.DOTALL | re.MULTILINE)
     manifest_data = open(os.path.join(g_project_root, "Package.swift")).read()
 
     def convert(match):
@@ -198,7 +208,8 @@ def parse_manifest():
             try:
                 return next(a for a in targets if a.name == targetName)
             except StopIteration:
-                # this target is not explicit in the manifest: it is an implicit target
+                # this target is not explicit in the manifest: it is an
+                # implicit target
                 b = Target(targetName)
                 targets.append(b)
                 return b
@@ -207,6 +218,7 @@ def parse_manifest():
     # fill dependency graph and set dependencies back to strings
     def convert(target):
         myset = set()
+
         def recurse(root):
             deps = []
             for dep in root.dependencies:
@@ -224,6 +236,7 @@ g_source_root = os.path.join(g_project_root, "Sources")
 targets = parse_manifest()
 target_map = dict((t.name, t) for t in targets)
 
+
 def create_bootstrap_files(sandbox_path, args):
     # Write out the build file.
     output = StringIO()
@@ -284,7 +297,8 @@ def create_bootstrap_files(sandbox_path, args):
         print("  %s:" % json.dumps(predecessor_node), file=output)
         print("    tool: phony", file=output)
         print("    inputs: %s" % json.dumps(
-            [target_map[name].virtual_node for name in target.dependencies]), file=output)
+            [target_map[name].virtual_node for name in target.dependencies]),
+            file=output)
         print("    outputs: %s" % json.dumps([predecessor_node]), file=output)
         print(file=output)
 
@@ -307,7 +321,8 @@ def create_bootstrap_files(sandbox_path, args):
         else:
             link_output_path = os.path.join(bin_dir, target.name)
 
-            link_command = [args.swiftc_path, '-o', pipes.quote(link_output_path)]
+            link_command = [args.swiftc_path,
+                            '-o', pipes.quote(link_output_path)]
             if args.sysroot:
                 link_command.extend(["-sdk", args.sysroot])
             if platform.system() == 'Darwin':
@@ -325,7 +340,10 @@ def create_bootstrap_files(sandbox_path, args):
         # Write out the link command.
         print("  %s:" % json.dumps(target.linked_virtual_node), file=output)
         print("    tool: shell", file=output)
-        print("    description: Link %s" % (target.name if target.is_library else link_output_path,), file=output)
+        if target.is_library:
+            print("    description: Link %s" % target.name, file=output)
+        else:
+            print("    description: Link %s" % link_output_path, file=output)
         print("    inputs: %s" % json.dumps(
             link_input_nodes + objects + linked_libraries), file=output)
         print("    outputs: %s" % json.dumps(
@@ -338,13 +356,15 @@ def create_bootstrap_files(sandbox_path, args):
         print("    tool: phony", file=output)
         print("    inputs: %s" % json.dumps(
             [target.linked_virtual_node]), file=output)
-        print("    outputs: %s" % json.dumps([target.virtual_node]), file=output)
+        print("    outputs: %s" % json.dumps([target.virtual_node]),
+              file=output)
         print(file=output)
 
     # Write the output file.
     write_file_if_changed(os.path.join(sandbox_path, "build.swift-build"),
                           output.getvalue())
 
+
 def process_runtime_libraries(build_path, args, bootstrap=False):
     if bootstrap:
         module_input_path = os.path.join(
@@ -391,7 +411,8 @@ def process_runtime_libraries(build_path, args, bootstrap=False):
         # error.
         tf = tempfile.NamedTemporaryFile(suffix=".swift")
         cmds = subprocess.check_output(
-            cmd + [tf.name, "-###"], universal_newlines=True).strip().split("\n")
+            cmd + [tf.name, "-###"],
+            universal_newlines=True).strip().split("\n")
 
         # Get the link command 'swiftc' used.
         link_cmd = shlex.split(cmds[-1])
@@ -408,10 +429,12 @@ def process_runtime_libraries(build_path, args, bootstrap=False):
             raise SystemExit("unable to understand 'swiftc' driver commands")
         del link_cmd[idx - 1]
         cmd = [arg for arg in link_cmd
-               if arg.endswith("swift_begin.o") or arg.endswith("swift_end.o") or (not arg.endswith(".o") and not arg.endswith(".autolink"))]
+               if arg.endswith(("swift_begin.o", "swift_end.o")) or
+               (not arg.endswith((".o", ".autolink")))]
     subprocess.check_call(cmd)
     return (runtime_module_path, runtime_lib_path)
 
+
 def get_swift_build_tool_path():
     # Search for a 'swift-build-tool' to use.
 
@@ -428,7 +451,8 @@ def get_swift_build_tool_path():
 
     # Next, search for it in PATH.
     try:
-        return subprocess.check_output(["which", "swift-build-tool"], universal_newlines=True).strip()
+        return subprocess.check_output(["which", "swift-build-tool"],
+                                       universal_newlines=True).strip()
     except:
         pass
 
@@ -446,6 +470,7 @@ def get_swift_build_tool_path():
     # If all else failed, report an error.
     error("unable to find 'swift-build-tool' tool for bootstrap build")
 
+
 def main():
     parser = argparse.ArgumentParser(
         usage="%(prog)s [options] [clean|all|test|install]",
@@ -517,9 +542,11 @@ def main():
     args.sbt_path = os.path.abspath(
         args.sbt_path or get_swift_build_tool_path())
 
-    # Due to bug in Xcode where SWIFT_EXEC is not set correctly by downloadable toolchain
+    # Due to bug in Xcode where SWIFT_EXEC is not set correctly by downloadable
+    # toolchain
     if os.getenv("XCODE_DEFAULT_TOOLCHAIN_OVERRIDE"):
-        args.swiftc = os.path.join(os.getenv("XCODE_DEFAULT_TOOLCHAIN_OVERRIDE"), "usr/bin/swiftc")
+        args.swiftc = os.path.join(
+            os.getenv("XCODE_DEFAULT_TOOLCHAIN_OVERRIDE"), "usr/bin/swiftc")
 
     # Create or update the bootstrap files.
     create_bootstrap_files(sandbox_path, args)
@@ -561,7 +588,7 @@ def main():
     if args.sysroot:
         env_cmd.append("SYSROOT=" + args.sysroot)
 
-    # We need to embed an RPATH so swift-{build,test} can find the core 
+    # We need to embed an RPATH so swift-{build,test} can find the core
     # libraries.
     if platform.system() == 'Linux':
         embed_rpath = "$ORIGIN/../lib/swift/linux"