pylint a few python scripts and lint in lint.sh (flutter/engine#33675)

engine/src/flutter/.pylintrc

@@ -0,0 +1,254 @@
+[MASTER]
+
+# Specify a configuration file.
+#rcfile=
+
+# Python code to execute, usually for sys.path manipulation such as
+# pygtk.require().
+#init-hook=
+
+# Add files or directories to the blocklist. They should be base names, not
+# paths.
+ignore=CVS,.git,out
+
+# Pickle collected data for later comparisons.
+persistent=yes
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=
+    pylint_quotes
+
+
+# Configure quote preferences.
+string-quote = single-avoid-escape
+triple-quote = double
+docstring-quote = double
+
+
+[MESSAGES CONTROL]
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time.
+#enable=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifier separated by comma (,) or put this option
+# multiple time (only on the command line, not in the configuration file where
+# it should appear only once).
+disable=
+    exec-used,
+    fixme,
+    missing-class-docstring,
+    missing-function-docstring,
+    missing-module-docstring,
+    too-few-public-methods,
+    too-many-branches,
+    too-many-lines,
+    too-many-return-statements,
+    too-many-statements,
+
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html
+output-format=text
+
+# Put messages in a separate file for each module / package specified on the
+# command line instead of printing them on stdout. Reports (if any) will be
+# written in a file name "pylint_global.[txt|html]".
+files-output=no
+
+# Tells whether to display a full report or only the messages
+# CHANGED:
+reports=no
+
+# Activate the evaluation score.
+score=no
+
+# Python expression which should return a note less than 10 (10 is the highest
+# note). You have access to the variables errors warning, statement which
+# respectively contain the number of errors / warnings messages and the total
+# number of statements analyzed. This is used by the global evaluation report
+# (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the beginning of the name of dummy variables
+# (i.e. not used).
+dummy-variables-rgx=_|dummy
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+
+[TYPECHECK]
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# mixin class is detected if its name ends with "mixin" (case insensitive).
+ignore-mixin-members=yes
+
+# List of classes names for which member attributes should not be checked
+# (useful for classes with attributes dynamically set).
+ignored-classes=SQLObject,twisted.internet.reactor,hashlib,google.appengine.api.memcache
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E0201 when accessed. Python regular
+# expressions are accepted.
+generated-members=REQUEST,acl_users,aq_parent,multiprocessing.managers.SyncManager
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=FIXME,XXX,TODO
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=10
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+# yapf is configured (in .style.yapf) to format to a line length of 80, but
+# sometimes it is not successful if a comment or string literal isn't already
+# well-formatted. Therefore, we use pylint to put a hard limit somewhere
+# further out at a point where manual formatting should be done.
+max-line-length=100
+
+# Maximum number of lines in a module
+max-module-lines=1000
+
+# String used as indentation unit. This is usually " " (4 spaces) or "\t" (1
+# tab).
+# CHANGED:
+indent-string='  '
+
+
+[BASIC]
+
+# List of builtins function names that should not be used, separated by a comma
+bad-functions=map,filter,apply,input
+
+# Regular expression which should only match correct module names
+module-rgx=(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$
+
+# Regular expression which should only match correct module level names
+const-rgx=(([A-Z_][A-Z0-9_]*)|(__.*__))$
+
+# Regular expression which should only match correct class names
+class-rgx=[A-Z_][a-zA-Z0-9]+$
+
+# Regular expression which should only match correct function names
+function-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct method names
+method-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct instance attribute names
+attr-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct argument names
+argument-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct variable names
+variable-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct list comprehension /
+# generator expression variable names
+inlinevar-rgx=[A-Za-z_][A-Za-z0-9_]*$
+
+# Good variable names which should always be accepted, separated by a comma
+good-names=i,j,k,ex,Run,_
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=foo,bar,baz,toto,tutu,tata
+
+# Regular expression which should only match functions or classes name which do
+# not require a docstring
+no-docstring-rgx=__.*__
+
+
+[DESIGN]
+
+# Maximum number of arguments for function / method
+max-args=5
+
+# Argument names that match this expression will be ignored. Default to name
+# with leading underscore
+ignored-argument-names=_.*
+
+# Maximum number of locals for function / method body
+max-locals=25
+
+# Maximum number of return / yield for function / method body
+max-returns=6
+
+# Maximum number of branch for function / method body
+max-branchs=12
+
+# Maximum number of statements in function / method body
+max-statements=50
+
+# Maximum number of parents for a class (see R0901).
+max-parents=7
+
+# Maximum number of attributes for a class (see R0902).
+max-attributes=7
+
+# Minimum number of public methods for a class (see R0903).
+min-public-methods=2
+
+# Maximum number of public methods for a class (see R0904).
+max-public-methods=20
+
+
+[CLASSES]
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,__new__,setUp
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=regsub,string,TERMIOS,Bastion,rexec
+
+# Create a graph of every (i.e. internal and external) dependencies in the
+# given file (report RP0402 must not be disabled)
+import-graph=
+
+# Create a graph of external dependencies in the given file (report RP0402 must
+# not be disabled)
+ext-import-graph=
+
+# Create a graph of internal dependencies in the given file (report RP0402 must
+# not be disabled)
+int-import-graph=
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=Exception

engine/src/flutter/build/copy_info_plist.py

@@ -10,33 +10,34 @@ engine.
 
 Precondition: $CWD/../../flutter is the path to the flutter engine repo.
 
-usage: copy_info_plist.py --source <src_path> --destination <dest_path> --bitcode --minversion=<deployment_target>
+usage: copy_info_plist.py --source <src_path> --destination <dest_path>
+                          --bitcode --minversion=<deployment_target>
 """
 
+import argparse
+import os
 import subprocess
 
-import argparse
-import sys
 import git_revision
-import os
 
 
-def GetClangVersion(bitcode):
+def get_clang_version(bitcode):
   clang_executable = str(
       os.path.join(
-          "..", "..", "buildtools", "mac-x64", "clang", "bin", "clang++"
+          '..', '..', 'buildtools', 'mac-x64', 'clang', 'bin', 'clang++'
       )
   )
   if bitcode:
-    clang_executable = "clang++"
-  version = subprocess.check_output([clang_executable, "--version"])
+    clang_executable = 'clang++'
+  version = subprocess.check_output([clang_executable, '--version'])
   return version.splitlines()[0]
 
 
 def main():
 
   parser = argparse.ArgumentParser(
-      description='Copies the Info.plist and adds extra fields to it like the git hash of the engine'
+      description='Copies the Info.plist and adds extra fields to it like the '
+      'git hash of the engine'
   )
 
   parser.add_argument(
@@ -61,19 +62,19 @@ def main():
   args = parser.parse_args()
 
   text = open(args.source).read()
-  engine_path = os.path.join(os.getcwd(), "..", "..", "flutter")
-  revision = git_revision.GetRepositoryVersion(engine_path)
+  engine_path = os.path.join(os.getcwd(), '..', '..', 'flutter')
+  revision = git_revision.get_repository_version(engine_path)
   bitcode = args.bitcode is not None
-  clang_version = GetClangVersion(bitcode)
+  clang_version = get_clang_version(bitcode)
   text = text.format(
       revision=revision,
       clang_version=clang_version,
       min_version=args.minversion
   )
 
-  with open(args.destination, "w") as outfile:
+  with open(args.destination, 'w') as outfile:
     outfile.write(text)
 
 
-if __name__ == "__main__":
+if __name__ == '__main__':
   main()

engine/src/flutter/build/dart/tools/dart_package_name.py

@@ -7,21 +7,20 @@
 """This script outputs the package name specified in the pubspec.yaml"""
 
 import argparse
-import os
 import sys
 
 
 # TODO(johnmccutchan): Use the yaml package to parse.
-def PackageName(line):
-  assert line.startswith("name:")
-  return line.split(":")[1].strip()
+def package_name(line):
+  assert line.startswith('name:')
+  return line.split(':')[1].strip()
 
 
 def main(pubspec_file):
-  source_file = open(pubspec_file, "r")
+  source_file = open(pubspec_file, 'r')
   for line in source_file:
-    if line.startswith("name:"):
-      print(PackageName(line))
+    if line.startswith('name:'):
+      print(package_name(line))
       return 0
   source_file.close()
   # Couldn't find it.
@@ -30,16 +29,16 @@ def main(pubspec_file):
 
 if __name__ == '__main__':
   parser = argparse.ArgumentParser(
-      description="This script outputs the package name specified in the"
-      "pubspec.yaml"
+      description='This script outputs the package name specified in the '
+      'pubspec.yaml'
   )
   parser.add_argument(
-      "--pubspec",
-      dest="pubspec_file",
-      metavar="<pubspec-file>",
+      '--pubspec',
+      dest='pubspec_file',
+      metavar='<pubspec-file>',
       type=str,
       required=True,
-      help="Path to pubspec file"
+      help='Path to pubspec file'
   )
   args = parser.parse_args()
   sys.exit(main(args.pubspec_file))

engine/src/flutter/build/dart/tools/dart_pkg.py

@@ -14,10 +14,10 @@ import shutil
 import subprocess
 import sys
 
-USE_LINKS = sys.platform != "win32"
+USE_LINKS = sys.platform != 'win32'
 
 DART_ANALYZE = os.path.join(
-    os.path.dirname(os.path.abspath(__file__)), "dart_analyze.py"
+    os.path.dirname(os.path.abspath(__file__)), 'dart_analyze.py'
 )
 
 
@@ -38,7 +38,7 @@ def ensure_dir_exists(path):
 def has_pubspec_yaml(paths):
   for path in paths:
     _, filename = os.path.split(path)
-    if 'pubspec.yaml' == filename:
+    if filename == 'pubspec.yaml':
       return True
   return False
 
@@ -47,14 +47,14 @@ def link(from_root, to_root):
   ensure_dir_exists(os.path.dirname(to_root))
   try:
     os.unlink(to_root)
-  except OSError as e:
-    if e.errno == errno.ENOENT:
+  except OSError as err:
+    if err.errno == errno.ENOENT:
       pass
 
   try:
     os.symlink(from_root, to_root)
-  except OSError as e:
-    if e.errno == errno.EEXIST:
+  except OSError as err:
+    if err.errno == errno.EEXIST:
       pass
 
 
@@ -72,7 +72,7 @@ def copy(from_root, to_root, filter_func=None):
     # filter_func expects paths not names, so wrap it to make them absolute.
     wrapped_filter = None
     if filter_func:
-      wrapped_filter = lambda name: filter_func(os.path.join(root, name))
+      wrapped_filter = lambda name, rt=root: filter_func(os.path.join(rt, name))
 
     for name in filter(wrapped_filter, files):
       from_path = os.path.join(root, name)
@@ -101,8 +101,8 @@ def link_if_possible(from_root, to_root):
 def remove_if_exists(path):
   try:
     os.remove(path)
-  except OSError as e:
-    if e.errno != errno.ENOENT:
+  except OSError as err:
+    if err.errno != errno.ENOENT:
       raise
 
 
@@ -112,7 +112,7 @@ def list_files(from_root, filter_func=None):
     # filter_func expects paths not names, so wrap it to make them absolute.
     wrapped_filter = None
     if filter_func:
-      wrapped_filter = lambda name: filter_func(os.path.join(root, name))
+      wrapped_filter = lambda name, rt=root: filter_func(os.path.join(rt, name))
     for name in filter(wrapped_filter, files):
       path = os.path.join(root, name)
       file_list.append(path)
@@ -125,9 +125,9 @@ def remove_broken_symlink(path):
     return
   try:
     link_path = os.readlink(path)
-  except OSError as e:
+  except OSError as err:
     # Path was not a symlink.
-    if e.errno == errno.EINVAL:
+    if err.errno == errno.EINVAL:
       pass
   else:
     if not os.path.exists(link_path):
@@ -144,20 +144,20 @@ def remove_broken_symlinks(root_dir):
 
 
 def analyze_entrypoints(dart_sdk, package_root, entrypoints):
-  cmd = ["python", DART_ANALYZE]
-  cmd.append("--dart-sdk")
+  cmd = ['python', DART_ANALYZE]
+  cmd.append('--dart-sdk')
   cmd.append(dart_sdk)
-  cmd.append("--entrypoints")
+  cmd.append('--entrypoints')
   cmd.extend(entrypoints)
-  cmd.append("--package-root")
+  cmd.append('--package-root')
   cmd.append(package_root)
-  cmd.append("--no-hints")
+  cmd.append('--no-hints')
   try:
     subprocess.check_output(cmd, stderr=subprocess.STDOUT)
-  except subprocess.CalledProcessError as e:
+  except subprocess.CalledProcessError as err:
     print('Failed analyzing %s' % entrypoints)
-    print(e.output)
-    return e.returncode
+    print(err.output)
+    return err.returncode
   return 0
 
 
@@ -248,7 +248,7 @@ def main():
 
   target_dir = os.path.join(args.pkg_directory, args.package_name)
   target_packages_dir = os.path.join(target_dir, 'packages')
-  lib_path = os.path.join(target_dir, "lib")
+  lib_path = os.path.join(target_dir, 'lib')
   ensure_dir_exists(lib_path)
 
   mappings = {}
@@ -312,9 +312,9 @@ def main():
 
   # If any entrypoints are defined, write them to disk so that the analyzer
   # test can find them.
-  with open(args.entries_file, 'w') as f:
+  with open(args.entries_file, 'w') as file:
     for entrypoint in entrypoint_targets:
-      f.write(entrypoint + '\n')
+      file.write(entrypoint + '\n')
 
   # Write stamp file.
   with open(args.stamp_file, 'w'):

engine/src/flutter/build/generate_coverage.py

@@ -12,41 +12,106 @@ import errno
 import shutil
 
 
-def GetLLVMBinDirectory():
+def get_llvm_bin_directory():
   buildtool_dir = os.path.join(
-      os.path.dirname(os.path.realpath(__file__)), "../../buildtools"
+      os.path.dirname(os.path.realpath(__file__)), '../../buildtools'
   )
-  platform_dir = ""
+  platform_dir = ''
   if sys.platform.startswith('linux'):
-    platform_dir = "linux-x64"
+    platform_dir = 'linux-x64'
   elif sys.platform == 'darwin':
-    platform_dir = "mac-x64"
+    platform_dir = 'mac-x64'
   else:
-    raise Exception("Unknown/Unsupported platform.")
+    raise Exception('Unknown/Unsupported platform.')
   llvm_bin_dir = os.path.abspath(
-      os.path.join(buildtool_dir, platform_dir, "clang/bin")
+      os.path.join(buildtool_dir, platform_dir, 'clang/bin')
   )
   if not os.path.exists(llvm_bin_dir):
-    raise Exception("LLVM directory %s double not be located." % llvm_bin_dir)
+    raise Exception('LLVM directory %s double not be located.' % llvm_bin_dir)
   return llvm_bin_dir
 
 
-def MakeDirs(new_dir):
+def make_dirs(new_dir):
   """A wrapper around os.makedirs() that emulates "mkdir -p"."""
   try:
     os.makedirs(new_dir)
-  except OSError as e:
-    if e.errno != errno.EEXIST:
+  except OSError as err:
+    if err.errno != errno.EEXIST:
       raise
 
 
-def RemoveIfExists(path):
+def remove_if_exists(path):
   if os.path.isdir(path) and not os.path.islink(path):
     shutil.rmtree(path)
   elif os.path.exists(path):
     os.remove(path)
 
 
+def collect_profiles(args):
+  raw_profiles = []
+  binaries = []
+
+  # Run all unit tests and collect raw profiles.
+  for test in args.tests:
+    absolute_test_path = os.path.abspath(test)
+    absolute_test_dir = os.path.dirname(absolute_test_path)
+    test_name = os.path.basename(absolute_test_path)
+
+    if not os.path.exists(absolute_test_path):
+      print('Path %s does not exist.' % absolute_test_path)
+      return -1
+
+    unstripped_test_path = os.path.join(
+        absolute_test_dir, 'exe.unstripped', test_name
+    )
+
+    if os.path.exists(unstripped_test_path):
+      binaries.append(unstripped_test_path)
+    else:
+      binaries.append(absolute_test_path)
+
+    raw_profile = absolute_test_path + '.rawprofile'
+
+    remove_if_exists(raw_profile)
+
+    print(
+        'Running test %s to gather profile.' %
+        os.path.basename(absolute_test_path)
+    )
+
+    test_command = [absolute_test_path]
+
+    test_args = ' '.join(args.test_args).split()
+
+    if test_args is not None:
+      test_command += test_args
+
+    subprocess.check_call(test_command, env={'LLVM_PROFILE_FILE': raw_profile})
+
+    if not os.path.exists(raw_profile):
+      print('Could not find raw profile data for unit test run %s.' % test)
+      print('Did you build with the --coverage flag?')
+      return -1
+
+    raw_profiles.append(raw_profile)
+
+  return (binaries, raw_profiles)
+
+
+def merge_profiles(llvm_bin_dir, raw_profiles, output):
+  # Merge all raw profiles into a single profile.
+  profdata_binary = os.path.join(llvm_bin_dir, 'llvm-profdata')
+
+  print('Merging %d raw profile(s) into single profile.' % len(raw_profiles))
+  merged_profile_path = os.path.join(output, 'all.profile')
+  remove_if_exists(merged_profile_path)
+  merge_command = [profdata_binary, 'merge', '-sparse'
+                  ] + raw_profiles + ['-o', merged_profile_path]
+  subprocess.check_call(merge_command)
+  print('Done.')
+  return merged_profile_path
+
+
 def main():
   parser = argparse.ArgumentParser()
 
@@ -86,59 +151,14 @@ def main():
 
   output = os.path.abspath(args.output)
 
-  MakeDirs(output)
+  make_dirs(output)
 
-  generate_all_reports = args.format == "all"
+  generate_all_reports = args.format == 'all'
 
-  raw_profiles = []
-  binaries = []
-
-  # Run all unit tests and collect raw profiles.
-  for test in args.tests:
-    absolute_test_path = os.path.abspath(test)
-    absolute_test_dir = os.path.dirname(absolute_test_path)
-    test_name = os.path.basename(absolute_test_path)
-
-    if not os.path.exists(absolute_test_path):
-      print("Path %s does not exist." % absolute_test_path)
-      return -1
-
-    unstripped_test_path = os.path.join(
-        absolute_test_dir, "exe.unstripped", test_name
-    )
-
-    if os.path.exists(unstripped_test_path):
-      binaries.append(unstripped_test_path)
-    else:
-      binaries.append(absolute_test_path)
-
-    raw_profile = absolute_test_path + ".rawprofile"
-
-    RemoveIfExists(raw_profile)
-
-    print(
-        "Running test %s to gather profile." %
-        os.path.basename(absolute_test_path)
-    )
-
-    test_command = [absolute_test_path]
-
-    test_args = ' '.join(args.test_args).split()
-
-    if test_args is not None:
-      test_command += test_args
-
-    subprocess.check_call(test_command, env={"LLVM_PROFILE_FILE": raw_profile})
-
-    if not os.path.exists(raw_profile):
-      print("Could not find raw profile data for unit test run %s." % test)
-      print("Did you build with the --coverage flag?")
-      return -1
-
-    raw_profiles.append(raw_profile)
+  binaries, raw_profiles = collect_profiles(args)
 
   if len(raw_profiles) == 0:
-    print("No raw profiles could be generated.")
+    print('No raw profiles could be generated.')
     return -1
 
   binaries_flag = []
@@ -146,63 +166,52 @@ def main():
     binaries_flag.append('-object')
     binaries_flag.append(binary)
 
-  llvm_bin_dir = GetLLVMBinDirectory()
+  llvm_bin_dir = get_llvm_bin_directory()
 
-  # Merge all raw profiles into a single profile.
-  profdata_binary = os.path.join(llvm_bin_dir, "llvm-profdata")
-
-  print("Merging %d raw profile(s) into single profile." % len(raw_profiles))
-  merged_profile_path = os.path.join(output, "all.profile")
-  RemoveIfExists(merged_profile_path)
-  merge_command = [profdata_binary, "merge", "-sparse"
-                  ] + raw_profiles + ["-o", merged_profile_path]
-  subprocess.check_call(merge_command)
-  print("Done.")
+  merged_profile_path = merge_profiles(llvm_bin_dir, raw_profiles, output)
 
   if not os.path.exists(merged_profile_path):
-    print("Could not generate or find merged profile %s." % merged_profile_path)
+    print('Could not generate or find merged profile %s.' % merged_profile_path)
     return -1
 
-  llvm_cov_binary = os.path.join(llvm_bin_dir, "llvm-cov")
-  instr_profile_flag = "-instr-profile=%s" % merged_profile_path
-  ignore_flags = "-ignore-filename-regex=third_party|unittest|fixture"
+  llvm_cov_binary = os.path.join(llvm_bin_dir, 'llvm-cov')
+  instr_profile_flag = '-instr-profile=%s' % merged_profile_path
+  ignore_flags = '-ignore-filename-regex=third_party|unittest|fixture'
 
   # Generate the HTML report if specified.
   if generate_all_reports or args.format == 'html':
-    print("Generating HTML report.")
-    show_command = [llvm_cov_binary, "show"] + binaries_flag + [
+    print('Generating HTML report.')
+    subprocess.check_call([llvm_cov_binary, 'show'] + binaries_flag + [
         instr_profile_flag,
-        "-format=html",
-        "-output-dir=%s" % output,
-        "-tab-size=2",
+        '-format=html',
+        '-output-dir=%s' % output,
+        '-tab-size=2',
         ignore_flags,
-    ]
-    subprocess.check_call(show_command)
-    print("Done.")
+    ])
+    print('Done.')
 
   # Generate a report summary if specified.
   if generate_all_reports or args.format == 'summary':
-    print("Generating a summary report.")
-    report_command = [llvm_cov_binary, "report"] + binaries_flag + [
+    print('Generating a summary report.')
+    subprocess.check_call([llvm_cov_binary, 'report'] + binaries_flag + [
         instr_profile_flag,
         ignore_flags,
-    ]
-    subprocess.check_call(report_command)
-    print("Done.")
+    ])
+    print('Done.')
 
   # Generate a lcov summary if specified.
   if generate_all_reports or args.format == 'lcov':
-    print("Generating LCOV report.")
+    print('Generating LCOV report.')
     lcov_file = os.path.join(output, 'coverage.lcov')
-    RemoveIfExists(lcov_file)
-    lcov_command = [llvm_cov_binary, "export"] + binaries_flag + [
-        instr_profile_flag,
-        ignore_flags,
-        "-format=lcov",
-    ]
+    remove_if_exists(lcov_file)
     with open(lcov_file, 'w') as lcov_redirect:
-      subprocess.check_call(lcov_command, stdout=lcov_redirect)
-    print("Done.")
+      subprocess.check_call([llvm_cov_binary, 'export'] + binaries_flag + [
+          instr_profile_flag,
+          ignore_flags,
+          '-format=lcov',
+      ],
+                            stdout=lcov_redirect)
+    print('Done.')
 
   return 0
 

engine/src/flutter/build/get_concurrent_jobs.py

@@ -28,45 +28,46 @@ import sys
 UNITS = {'B': 1, 'KB': 2**10, 'MB': 2**20, 'GB': 2**30, 'TB': 2**40}
 
 
+# pylint: disable=line-too-long
 # See https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex
 # and https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/ns-sysinfoapi-memorystatusex
+# pylint: enable=line-too-long
 class MEMORYSTATUSEX(ctypes.Structure):
   _fields_ = [
-      ("dwLength", ctypes.c_ulong),
-      ("dwMemoryLoad", ctypes.c_ulong),
-      ("ullTotalPhys", ctypes.c_ulonglong),
-      ("ullAvailPhys", ctypes.c_ulonglong),
-      ("ullTotalPageFile", ctypes.c_ulonglong),
-      ("ullAvailPageFile", ctypes.c_ulonglong),
-      ("ullTotalVirtual", ctypes.c_ulonglong),
-      ("ullAvailVirtual", ctypes.c_ulonglong),
-      ("sullAvailExtendedVirtual", ctypes.c_ulonglong),
+      ('dwLength', ctypes.c_ulong),
+      ('dwMemoryLoad', ctypes.c_ulong),
+      ('ullTotalPhys', ctypes.c_ulonglong),
+      ('ullAvailPhys', ctypes.c_ulonglong),
+      ('ullTotalPageFile', ctypes.c_ulonglong),
+      ('ullAvailPageFile', ctypes.c_ulonglong),
+      ('ullTotalVirtual', ctypes.c_ulonglong),
+      ('ullAvailVirtual', ctypes.c_ulonglong),
+      ('sullAvailExtendedVirtual', ctypes.c_ulonglong),
   ]
 
 
-def GetTotalMemory():
+def get_total_memory():
   if sys.platform in ('win32', 'cygwin'):
     stat = MEMORYSTATUSEX(dwLength=ctypes.sizeof(MEMORYSTATUSEX))
     success = ctypes.windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(stat))
     return stat.ullTotalPhys if success else 0
-  elif sys.platform.startswith('linux'):
-    if os.path.exists("/proc/meminfo"):
-      with open("/proc/meminfo") as meminfo:
+  if sys.platform.startswith('linux'):
+    if os.path.exists('/proc/meminfo'):
+      with open('/proc/meminfo') as meminfo:
         memtotal_re = re.compile(r'^MemTotal:\s*(\d*)\s*kB')
         for line in meminfo:
           match = memtotal_re.match(line)
           if match:
             return float(match.group(1)) * 2**10
-  elif sys.platform == 'darwin':
+  if sys.platform == 'darwin':
     try:
       return int(subprocess.check_output(['sysctl', '-n', 'hw.memsize']))
-    except Exception:
+    except:  # pylint: disable=bare-except
       return 0
-  else:
-    return 0
+  return 0
 
 
-def ParseSize(string):
+def parse_size(string):
   i = next(i for (i, c) in enumerate(string) if not c.isdigit())
   number = string[:i].strip()
   unit = string[i:].strip()
@@ -78,12 +79,12 @@ class ParseSizeAction(argparse.Action):
   def __call__(self, parser, args, values, option_string=None):
     sizes = getattr(args, self.dest, [])
     for value in values:
-      (k, v) = value.split('=', 1)
-      sizes.append((k, ParseSize(v)))
+      (k, val) = value.split('=', 1)
+      sizes.append((k, parse_size(val)))
     setattr(args, self.dest, sizes)
 
 
-def Main():
+def main():
   parser = argparse.ArgumentParser()
   parser.add_argument(
       '--memory-per-job',
@@ -95,13 +96,13 @@ def Main():
   )
   parser.add_argument(
       '--reserve-memory',
-      type=ParseSize,
+      type=parse_size,
       default=0,
       help='The amount of memory to be held out of the amount for jobs to use.'
   )
   args = parser.parse_args()
 
-  total_memory = GetTotalMemory()
+  total_memory = get_total_memory()
 
   # Ensure the total memory used in the calculation below is at least 0
   mem_total_bytes = max(0, total_memory - args.reserve_memory)
@@ -109,7 +110,7 @@ def Main():
   # Ensure the number of cpus used in the calculation below is at least 1
   try:
     cpu_cap = multiprocessing.cpu_count()
-  except:
+  except:  # pylint: disable=bare-except
     cpu_cap = 1
 
   concurrent_jobs = {}
@@ -126,4 +127,4 @@ def Main():
 
 
 if __name__ == '__main__':
-  sys.exit(Main())
+  sys.exit(main())

engine/src/flutter/build/git_revision.py

@@ -12,18 +12,18 @@ import os
 import argparse
 
 
-def IsWindows():
+def is_windows():
   os_id = sys.platform
   return os_id.startswith('win32') or os_id.startswith('cygwin')
 
 
-def GetRepositoryVersion(repository):
-  "Returns the Git HEAD for the supplied repository path as a string."
+def get_repository_version(repository):
+  'Returns the Git HEAD for the supplied repository path as a string.'
   if not os.path.exists(repository):
-    raise IOError("path doesn't exist")
+    raise IOError('path does not exist')
 
   git = 'git'
-  if IsWindows():
+  if is_windows():
     git = 'git.bat'
   version = subprocess.check_output([
       git,
@@ -48,7 +48,7 @@ def main():
 
   args = parser.parse_args()
   repository = os.path.abspath(args.repository)
-  version = GetRepositoryVersion(repository)
+  version = get_repository_version(repository)
   print(version.strip())
 
   return 0

engine/src/flutter/build/zip.py

@@ -14,7 +14,7 @@ import sys
 
 def _zip_dir(path, zip_file, prefix):
   path = path.rstrip('/\\')
-  for root, dirs, files in os.walk(path):
+  for root, _, files in os.walk(path):
     for file in files:
       if os.path.islink(os.path.join(root, file)):
         add_symlink(

engine/src/flutter/ci/deps_parser.py

@@ -19,35 +19,35 @@ CHECKOUT_ROOT = os.path.realpath(os.path.join(SCRIPT_DIR, '..'))
 
 
 # Used in parsing the DEPS file.
-class VarImpl(object):
+class VarImpl:
   _env_vars = {
-      "host_cpu": "x64",
-      "host_os": "linux",
+      'host_cpu': 'x64',
+      'host_os': 'linux',
   }
 
   def __init__(self, local_scope):
     self._local_scope = local_scope
 
-  def Lookup(self, var_name):
+  def lookup(self, var_name):
     """Implements the Var syntax."""
-    if var_name in self._local_scope.get("vars", {}):
-      return self._local_scope["vars"][var_name]
+    if var_name in self._local_scope.get('vars', {}):
+      return self._local_scope['vars'][var_name]
     # Inject default values for env variables
     if var_name in self._env_vars:
       return self._env_vars[var_name]
-    raise Exception("Var is not defined: %s" % var_name)
+    raise Exception('Var is not defined: %s' % var_name)
 
 
-def ParseDepsFile(deps_file):
+def parse_deps_file(deps_file):
   local_scope = {}
   var = VarImpl(local_scope)
   global_scope = {
-      'Var': var.Lookup,
+      'Var': var.lookup,
       'deps_os': {},
   }
   # Read the content.
-  with open(deps_file, 'r') as fp:
-    deps_content = fp.read()
+  with open(deps_file, 'r') as file:
+    deps_content = file.read()
 
   # Eval the content.
   exec(deps_content, global_scope, local_scope)
@@ -55,22 +55,22 @@ def ParseDepsFile(deps_file):
   # Extract the deps and filter.
   deps = local_scope.get('deps', {})
   filtered_deps = []
-  for k, v in deps.items():
+  for val in deps.values():
     # We currently do not support packages or cipd which are represented
     # as dictionaries.
-    if isinstance(v, str):
-      filtered_deps.append(v)
+    if isinstance(val, str):
+      filtered_deps.append(val)
 
   return filtered_deps
 
 
-def WriteManifest(deps, manifest_file):
+def write_manifest(deps, manifest_file):
   print('\n'.join(sorted(deps)))
   with open(manifest_file, 'w') as manifest:
     manifest.write('\n'.join(sorted(deps)))
 
 
-def ParseArgs(args):
+def parse_args(args):
   args = args[1:]
   parser = argparse.ArgumentParser(
       description='A script to flatten a gclient DEPS file.'
@@ -94,12 +94,12 @@ def ParseArgs(args):
   return parser.parse_args(args)
 
 
-def Main(argv):
-  args = ParseArgs(argv)
-  deps = ParseDepsFile(args.deps)
-  WriteManifest(deps, args.output)
+def main(argv):
+  args = parse_args(argv)
+  deps = parse_deps_file(args.deps)
+  write_manifest(deps, args.output)
   return 0
 
 
 if __name__ == '__main__':
-  sys.exit(Main(sys.argv))
+  sys.exit(main(sys.argv))

engine/src/flutter/ci/firebase_testlab.py

@@ -11,14 +11,14 @@ import os
 import subprocess
 import sys
 
+BUCKET = 'gs://flutter_firebase_testlab'
 script_dir = os.path.dirname(os.path.realpath(__file__))
 buildroot_dir = os.path.abspath(os.path.join(script_dir, '..', '..'))
 out_dir = os.path.join(buildroot_dir, 'out')
-bucket = 'gs://flutter_firebase_testlab'
 error_re = re.compile(r'[EF]/flutter.+')
 
 
-def RunFirebaseTest(apk, results_dir):
+def run_firebase_test(apk, results_dir):
   # game-loop tests are meant for OpenGL apps.
   # This type of test will give the application a handle to a file, and
   # we'll write the timeline JSON to that file.
@@ -40,7 +40,7 @@ def RunFirebaseTest(apk, results_dir):
           '--timeout',
           '2m',
           '--results-bucket',
-          bucket,
+          BUCKET,
           '--results-dir',
           results_dir,
           '--device',
@@ -53,10 +53,10 @@ def RunFirebaseTest(apk, results_dir):
   return process
 
 
-def CheckLogcat(results_dir):
+def check_logcat(results_dir):
   logcat = subprocess.check_output([
       'gsutil', 'cat',
-      '%s/%s/*/logcat' % (bucket, results_dir)
+      '%s/%s/*/logcat' % (BUCKET, results_dir)
   ])
   if not logcat:
     sys.exit(1)
@@ -68,13 +68,13 @@ def CheckLogcat(results_dir):
     sys.exit(1)
 
 
-def CheckTimeline(results_dir):
-  du = subprocess.check_output([
+def check_timeline(results_dir):
+  gsutil_du = subprocess.check_output([
       'gsutil', 'du',
       '%s/%s/*/game_loop_results/results_scenario_0.json' %
-      (bucket, results_dir)
+      (BUCKET, results_dir)
   ]).strip()
-  if du == '0':
+  if gsutil_du == '0':
     print('Failed to produce a timeline.')
     sys.exit(1)
 
@@ -107,15 +107,16 @@ def main():
                                          cwd=script_dir).strip()
 
   results = []
+  apk = None
   for apk in apks:
     results_dir = '%s/%s/%s' % (
         os.path.basename(apk), git_revision, args.build_id
     )
-    process = RunFirebaseTest(apk, results_dir)
+    process = run_firebase_test(apk, results_dir)
     results.append((results_dir, process))
 
   for results_dir, process in results:
-    for line in iter(process.stdout.readline, ""):
+    for line in iter(process.stdout.readline, ''):
       print(line.strip())
     return_code = process.wait()
     if return_code != 0:
@@ -123,11 +124,11 @@ def main():
       sys.exit(return_code)
 
     print('Checking logcat for %s' % results_dir)
-    CheckLogcat(results_dir)
+    check_logcat(results_dir)
     # scenario_app produces a timeline, but the android image test does not.
     if 'scenario' in apk:
       print('Checking timeline for %s' % results_dir)
-      CheckTimeline(results_dir)
+      check_timeline(results_dir)
 
   return 0
 

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -12,6 +12,7 @@ LIBRARY: txt
 ORIGIN: ../../../flutter/LICENSE
 TYPE: LicenseType.bsd
 FILE: ../../../flutter/.clang-tidy
+FILE: ../../../flutter/.pylintrc
 FILE: ../../../flutter/.style.yapf
 FILE: ../../../flutter/DEPS
 FILE: ../../../flutter/assets/asset_manager.cc

engine/src/flutter/ci/lint.sh

@@ -29,6 +29,7 @@ function follow_links() (
 
 SCRIPT_DIR=$(follow_links "$(dirname -- "${BASH_SOURCE[0]}")")
 SRC_DIR="$(cd "$SCRIPT_DIR/../.."; pwd -P)"
+FLUTTER_DIR="$(cd "$SCRIPT_DIR/.."; pwd -P)"
 DART_BIN="${SRC_DIR}/third_party/dart/tools/sdks/dart-sdk/bin"
 DART="${DART_BIN}/dart"
 
@@ -43,3 +44,10 @@ cd "$SCRIPT_DIR"
   "$SRC_DIR/flutter/tools/clang_tidy/bin/main.dart" \
   --src-dir="$SRC_DIR" \
   "$@"
+
+cd "$FLUTTER_DIR"
+pylint-2.7 --rcfile=.pylintrc \
+  "build/" \
+  "ci/" \
+  "impeller/" \
+  "tools/gn"

engine/src/flutter/impeller/tools/build_metal_library.py

@@ -10,7 +10,7 @@ import os
 import subprocess
 
 
-def MakeDirectories(path):
+def make_directories(path):
   try:
     os.makedirs(path)
   except OSError as exc:
@@ -20,91 +20,91 @@ def MakeDirectories(path):
       raise
 
 
-def Main():
+def main():
   parser = argparse.ArgumentParser()
   parser.add_argument(
-      "--output",
+      '--output',
       type=str,
       required=True,
-      help="The location to generate the Metal library to."
+      help='The location to generate the Metal library to.'
   )
   parser.add_argument(
-      "--depfile", type=str, required=True, help="The location of the depfile."
+      '--depfile', type=str, required=True, help='The location of the depfile.'
   )
   parser.add_argument(
-      "--source",
+      '--source',
       type=str,
-      action="append",
+      action='append',
       required=True,
-      help="The source file to compile. Can be specified multiple times."
+      help='The source file to compile. Can be specified multiple times.'
   )
   parser.add_argument(
-      "--optimize",
-      action="store_true",
+      '--optimize',
+      action='store_true',
       default=False,
-      help="If available optimizations must be applied to the compiled Metal sources."
+      help='If available optimizations must be applied to the compiled Metal sources.'
   )
   parser.add_argument(
-      "--platform",
+      '--platform',
       required=True,
-      choices=["mac", "ios", "ios-simulator"],
-      help="Select the platform."
+      choices=['mac', 'ios', 'ios-simulator'],
+      help='Select the platform.'
   )
 
   args = parser.parse_args()
 
-  MakeDirectories(os.path.dirname(args.depfile))
+  make_directories(os.path.dirname(args.depfile))
 
   command = [
-      "xcrun",
+      'xcrun',
   ]
 
-  if args.platform == "mac":
+  if args.platform == 'mac':
     command += [
-        "-sdk",
-        "macosx",
+        '-sdk',
+        'macosx',
     ]
-  elif args.platform == "ios":
+  elif args.platform == 'ios':
     command += [
-        "-sdk",
-        "iphoneos",
+        '-sdk',
+        'iphoneos',
     ]
-  elif args.platform == "ios-simulator":
+  elif args.platform == 'ios-simulator':
     command += [
-        "-sdk",
-        "iphonesimulator",
+        '-sdk',
+        'iphonesimulator',
     ]
 
   command += [
-      "metal",
+      'metal',
       # These warnings are from generated code and would make no sense to the GLSL
       # author.
-      "-Wno-unused-variable",
+      '-Wno-unused-variable',
       # Both user and system header will be tracked.
-      "-MMD",
-      "-MF",
+      '-MMD',
+      '-MF',
       args.depfile,
-      "-o",
+      '-o',
       args.output,
   ]
 
   # The Metal standard must match the specification in impellerc.
-  if args.platform == "mac":
+  if args.platform == 'mac':
     command += [
-        "--std=macos-metal1.2",
+        '--std=macos-metal1.2',
     ]
-  elif args.platform == "ios":
+  elif args.platform == 'ios':
     command += [
-        "--std=ios-metal1.2",
-        "-mios-version-min=10.0",
+        '--std=ios-metal1.2',
+        '-mios-version-min=10.0',
     ]
 
   if args.optimize:
     command += [
         # Like -Os (and thus -O2), but reduces code size further.
-        "-Oz",
+        '-Oz',
         # Allow aggressive, lossy floating-point optimizations.
-        "-ffast-math",
+        '-ffast-math',
     ]
   else:
     command += [
@@ -112,12 +112,12 @@ def Main():
         # debugging but should be removed from release builds.
         # TODO(chinmaygarde): Use -frecord-sources when CI upgrades to
         # Xcode 13.
-        "-MO",
+        '-MO',
         # Assist the sampling profiler.
-        "-gline-tables-only",
-        "-g",
+        '-gline-tables-only',
+        '-g',
         # Optimize for debuggability.
-        "-Og",
+        '-Og',
     ]
 
   command += args.source
@@ -127,5 +127,5 @@ def Main():
 
 if __name__ == '__main__':
   if sys.platform != 'darwin':
-    raise Exception("This script only runs on Mac")
-  Main()
+    raise Exception('This script only runs on Mac')
+  main()

engine/src/flutter/impeller/tools/check_licenses.py

@@ -6,44 +6,44 @@ import argparse
 import os
 
 
-def ContainsLicenseBlock(source_file):
+def contains_license_block(source_file):
   # This check is somewhat easier than in the engine because all sources need to
   # have the same license.
-  py_license = '''# Copyright 2013 The Flutter Authors. All rights reserved.
+  py_license = """# Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.'''
-  c_license = py_license.replace("#", "//")
+# found in the LICENSE file."""
+  c_license = py_license.replace('#', '//')
 
   # Make sure we don't read the entire file into memory.
   read_size = (max(len(py_license), len(c_license)))
 
-  for license in [c_license, py_license]:
+  for lic in [c_license, py_license]:
     with open(source_file) as source:
-      if source.read(read_size).startswith(license):
+      if source.read(read_size).startswith(lic):
         return True
 
   return False
 
 
-def IsSourceFile(path):
+def is_source_file(path):
   known_extensions = [
-      ".cc",
-      ".cpp",
-      ".c",
-      ".h",
-      ".hpp",
-      ".py",
-      ".sh",
-      ".gn",
-      ".gni",
-      ".glsl",
-      ".sl.h",
-      ".vert",
-      ".frag",
-      ".tesc",
-      ".tese",
-      ".yaml",
-      ".dart",
+      '.cc',
+      '.cpp',
+      '.c',
+      '.h',
+      '.hpp',
+      '.py',
+      '.sh',
+      '.gn',
+      '.gni',
+      '.glsl',
+      '.sl.h',
+      '.vert',
+      '.frag',
+      '.tesc',
+      '.tese',
+      '.yaml',
+      '.dart',
   ]
   for extension in known_extensions:
     if os.path.basename(path).endswith(extension):
@@ -52,29 +52,29 @@ def IsSourceFile(path):
 
 
 # Checks that all source files have the same license preamble.
-def Main():
+def main():
   parser = argparse.ArgumentParser()
   parser.add_argument(
-      "--source-root", type=str, required=True, help="The source root."
+      '--source-root', type=str, required=True, help='The source root.'
   )
   args = parser.parse_args()
 
-  assert (os.path.exists(args.source_root))
+  assert os.path.exists(args.source_root)
 
   source_files = set()
 
-  for root, dirs, files in os.walk(os.path.abspath(args.source_root)):
+  for root, _, files in os.walk(os.path.abspath(args.source_root)):
     for file in files:
       file_path = os.path.join(root, file)
-      if IsSourceFile(file_path):
+      if is_source_file(file_path):
         source_files.add(file_path)
 
   for source_file in source_files:
-    if not ContainsLicenseBlock(source_file):
+    if not contains_license_block(source_file):
       raise Exception(
-          "Could not find valid license block in source ", source_file
+          'Could not find valid license block in source ', source_file
       )
 
 
 if __name__ == '__main__':
-  Main()
+  main()

engine/src/flutter/impeller/tools/xxd.py

@@ -2,15 +2,12 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import sys
-
 import argparse
 import errno
 import os
-import struct
 
 
-def MakeDirectories(path):
+def make_directories(path):
   try:
     os.makedirs(path)
   except OSError as exc:
@@ -22,77 +19,77 @@ def MakeDirectories(path):
 
 # Dump the bytes of file into a C translation unit.
 # This can be used to embed the file contents into a binary.
-def Main():
+def main():
   parser = argparse.ArgumentParser()
   parser.add_argument(
-      "--symbol-name",
+      '--symbol-name',
       type=str,
       required=True,
-      help="The name of the symbol referencing the data."
+      help='The name of the symbol referencing the data.'
   )
   parser.add_argument(
-      "--output-header",
+      '--output-header',
       type=str,
       required=True,
-      help="The header file containing the symbol reference."
+      help='The header file containing the symbol reference.'
   )
   parser.add_argument(
-      "--output-source",
+      '--output-source',
       type=str,
       required=True,
-      help="The source file containing the file bytes."
+      help='The source file containing the file bytes.'
   )
   parser.add_argument(
-      "--source",
+      '--source',
       type=str,
       required=True,
-      help="The source file whose contents to embed in the output source file."
+      help='The source file whose contents to embed in the output source file.'
   )
 
   args = parser.parse_args()
 
-  assert (os.path.exists(args.source))
+  assert os.path.exists(args.source)
 
   output_header = os.path.abspath(args.output_header)
   output_source = os.path.abspath(args.output_source)
   output_header_basename = output_header[output_header.rfind('/') + 1:]
 
-  MakeDirectories(os.path.dirname(output_header))
-  MakeDirectories(os.path.dirname(output_source))
+  make_directories(os.path.dirname(output_header))
+  make_directories(os.path.dirname(output_source))
 
-  with open(args.source, "rb") as source, open(output_source, "w") as output:
+  with open(args.source, 'rb') as source, open(output_source, 'w') as output:
     data_len = 0
-    output.write(f"#include \"{output_header_basename}\"\n")
-    output.write(f"const unsigned char impeller_{args.symbol_name}_data[] =\n")
-    output.write("{\n")
+    output.write(f'#include "{output_header_basename}"\n')
+    output.write(f'const unsigned char impeller_{args.symbol_name}_data[] =\n')
+    output.write('{\n')
     while True:
       byte = source.read(1)
       if not byte:
         break
       data_len += 1
-      output.write(f"{ord(byte)},")
-    output.write("};\n")
+      output.write(f'{ord(byte)},')
+    output.write('};\n')
     output.write(
-        f"const unsigned long impeller_{args.symbol_name}_length = {data_len};\n"
+        f'const unsigned long impeller_{args.symbol_name}_length = {data_len};\n'
     )
 
-  with open(output_header, "w") as output:
-    output.write("#pragma once\n")
-    output.write("#ifdef __cplusplus\n")
-    output.write("extern \"C\" {\n")
-    output.write("#endif\n\n")
+  with open(output_header, 'w') as output:
+    output.write('#pragma once\n')
+    output.write('#ifdef __cplusplus\n')
+    output.write('extern "C" {\n')
+    output.write('#endif\n\n')
 
     output.write(
-        f"extern const unsigned char impeller_{args.symbol_name}_data[];\n"
+        f'extern const unsigned char impeller_{args.symbol_name}_data[];\n'
     )
     output.write(
-        f"extern const unsigned long impeller_{args.symbol_name}_length;\n\n"
+        f'extern const unsigned long impeller_{args.symbol_name}_length;\n\n'
     )
 
-    output.write("#ifdef __cplusplus\n")
-    output.write("}\n")
-    output.write("#endif\n")
+    output.write('#ifdef __cplusplus\n')
+    output.write('}\n')
+    output.write('#endif\n')
 
 
 if __name__ == '__main__':
-  Main()
+  main()

engine/src/flutter/tools/gn

@@ -24,8 +24,6 @@ def get_out_dir(args):
   else:
     target_dir = ['host']
 
-  runtime_mode = args.runtime_mode
-
   target_dir.append(args.runtime_mode)
 
   if args.simulator:
@@ -81,7 +79,7 @@ def to_command_line(gn_args):
     """
 
   def merge(key, value):
-    if type(value) is bool:
+    if isinstance(value, bool):
       return '%s=%s' % (key, 'true' if value else 'false')
     return '%s="%s"' % (key, value)
 
@@ -94,6 +92,7 @@ def cpu_for_target_arch(arch):
     return 'x86'
   if arch in ['x64', 'arm64', 'simarm64', 'simdbc64', 'armsimdbc64']:
     return 'x64'
+  return None
 
 
 def is_host_build(args):
@@ -115,7 +114,7 @@ def can_use_prebuilt_dart(args):
   # platform agnostic artifacts (e.g. kernel snapshots), and a Dart SDK
   # targeting Fuchsia is not needed. So, it is safe to say that the prebuilt
   # Dart SDK in a Fuchsia build is the host prebuilt Dart SDK.
-  if args.target_os == None or args.target_os == 'fuchsia':
+  if args.target_os is None or args.target_os == 'fuchsia':
     if sys.platform.startswith(('cygwin', 'win')):
       prebuilt = 'windows-x64'
     elif sys.platform == 'darwin':
@@ -130,9 +129,9 @@ def can_use_prebuilt_dart(args):
     prebuilt = 'windows-%s' % args.windows_cpu
 
   prebuilts_dir = None
-  if prebuilt != None:
+  if prebuilt is not None:
     prebuilts_dir = os.path.join(SRC_ROOT, 'flutter', 'prebuilts', prebuilt)
-  return prebuilts_dir != None and os.path.isdir(prebuilts_dir)
+  return prebuilts_dir is not None and os.path.isdir(prebuilts_dir)
 
 
 # Returns the host machine operating system.
@@ -148,28 +147,28 @@ def get_host_os():
 # Rosetta. I.e., python3 is an x64 executable and we're on an arm64 Mac.
 def is_rosetta():
   if platform.system() == 'Darwin':
-    p = subprocess.Popen(['sysctl', '-in', 'sysctl.proc_translated'],
-                         stdout=subprocess.PIPE,
-                         stderr=subprocess.STDOUT)
-    output, _ = p.communicate()
+    proc = subprocess.Popen(['sysctl', '-in', 'sysctl.proc_translated'],
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.STDOUT)
+    output, _ = proc.communicate()
     return output.decode('utf-8').strip() == '1'
   return False
 
 
 # Returns the host machine CPU architecture.
-def get_host_cpu(args):
+def get_host_cpu():
   # If gn itself is running under Rosetta on an arm64 Mac, platform.machine()
   # will return x86_64; instead return the underlying host architecture.
   if is_rosetta():
     return 'arm64'
-  m = platform.machine()
-  if m in ['aarch64', 'arm64']:
+  machine = platform.machine()
+  if machine in ['aarch64', 'arm64']:
     return 'arm64'
-  if m in ['x86_64', 'AMD64', 'x64']:
+  if machine in ['x86_64', 'AMD64', 'x64']:
     return 'x64'
-  if m in ['i686', 'i386', 'x86']:
+  if machine in ['i686', 'i386', 'x86']:
     return 'x86'
-  raise Exception('Unknown CPU architecture: %s' % m)
+  raise Exception('Unknown CPU architecture: %s' % machine)
 
 
 # Returns the target CPU architecture.
@@ -182,8 +181,7 @@ def get_target_cpu(args):
   if args.target_os == 'ios':
     if args.simulator:
       return args.simulator_cpu
-    else:
-      return args.ios_cpu
+    return args.ios_cpu
   if args.target_os == 'mac':
     return args.mac_cpu
   if args.target_os == 'linux':
@@ -276,7 +274,7 @@ def to_gn_args(args):
   # Set OS, CPU arch for host or target build.
   if is_host_build(args):
     gn_args['host_os'] = get_host_os()
-    gn_args['host_cpu'] = get_host_cpu(args)
+    gn_args['host_cpu'] = get_host_cpu()
     gn_args['target_os'] = gn_args['host_os']
     gn_args['target_cpu'] = get_target_cpu(args)
     gn_args['dart_target_arch'] = gn_args['target_cpu']
@@ -394,7 +392,8 @@ def to_gn_args(args):
   else:
     if args.goma:
       print(
-          "GOMA usage was specified but can't be found, falling back to local builds. Set the GOMA_DIR environment variable to fix GOMA."
+          "GOMA usage was specified but can't be found, falling back to local "
+          'builds. Set the GOMA_DIR environment variable to fix GOMA.'
       )
     gn_args['use_goma'] = False
     gn_args['goma_dir'] = None
@@ -411,7 +410,7 @@ def to_gn_args(args):
     # Bitcode enabled builds using the current version of the toolchain leak
     # C++ symbols decorated with the availability attribute. Disable these
     # attributes in release modes till the toolchain is updated.
-    gn_args['skia_enable_api_available_macro'] = args.runtime_mode != "release"
+    gn_args['skia_enable_api_available_macro'] = args.runtime_mode != 'release'
 
   if sys.platform == 'darwin' and args.target_os not in ['android', 'fuchsia',
                                                          'wasm']:
@@ -519,8 +518,8 @@ def to_gn_args(args):
   elif args.target_os == 'fuchsia':
     # Read the default target api level from a file so we can update it with a roller
     with open(os.path.join(os.path.dirname(__file__),
-                           'fuchsia/target_api_level')) as f:
-      gn_args['fuchsia_target_api_level'] = int(f.read().strip())
+                           'fuchsia/target_api_level')) as file:
+      gn_args['fuchsia_target_api_level'] = int(file.read().strip())
 
   # Flags for Dart features:
   if args.use_mallinfo2:
@@ -557,8 +556,9 @@ def parse_args(args):
       '--dart-debug',
       default=False,
       action='store_true',
-      help='Enables assertions in the Dart VM. ' +
-      'Does not affect optimization levels. If you need to disable optimizations in Dart, use --full-dart-debug'
+      help='Enables assertions in the Dart VM. Does not affect optimization '
+      'levels. If you need to disable optimizations in Dart, use '
+      '--full-dart-debug'
   )
   parser.add_argument(
       '--no-dart-version-git-info',
@@ -570,8 +570,8 @@ def parse_args(args):
       '--full-dart-debug',
       default=False,
       action='store_true',
-      help='Implies --dart-debug ' +
-      'and also disables optimizations in the Dart VM making it easier to step through VM code in the debugger.'
+      help='Implies --dart-debug and also disables optimizations in the Dart '
+      'VM making it easier to step through VM code in the debugger.'
   )
 
   parser.add_argument(
@@ -635,12 +635,12 @@ def parse_args(args):
   parser.add_argument(
       '--xcode-symlinks',
       action='store_true',
-      help='Set to true for builds targeting macOS or iOS ' +
-      'when using goma. If set, symlinks to the Xcode provided sysroot and SDKs will be created in a generated '
-      +
-      'folder, which will avoid potential backend errors in Fuchsia RBE. Instead of specifying the flag on each invocation '
-      +
-      'the FLUTTER_GOMA_CREATE_XCODE_SYMLINKS environment variable may be set to 1 to achieve the same effect.'
+      help='Set to true for builds targeting macOS or iOS when using goma. If '
+      'set, symlinks to the Xcode provided sysroot and SDKs will be '
+      'created in a generated folder, which will avoid potential backend '
+      'errors in Fuchsia RBE. Instead of specifying the flag on each '
+      'invocation the FLUTTER_GOMA_CREATE_XCODE_SYMLINKS environment '
+      'variable may be set to 1 to achieve the same effect.'
   )
   parser.add_argument(
       '--no-xcode-symlinks',
@@ -856,7 +856,8 @@ def parse_args(args):
       '--trace-gn',
       default=False,
       action='store_true',
-      help='Write a GN trace log (gn_trace.json) in the Chromium tracing format in the build directory.'
+      help='Write a GN trace log (gn_trace.json) in the Chromium tracing '
+      'format in the build directory.'
   )
 
   # Verbose output.
@@ -901,11 +902,11 @@ def main(argv):
   if args.verbose:
     command.append('-v')
 
-  print("Generating GN files in: %s" % out_dir)
+  print('Generating GN files in: %s' % out_dir)
   try:
     gn_call_result = subprocess.call(command, cwd=SRC_ROOT)
   except subprocess.CalledProcessError as exc:
-    print("Failed to generate gn files: ", exc.returncode, exc.output)
+    print('Failed to generate gn files: ', exc.returncode, exc.output)
     sys.exit(1)
 
   return gn_call_result