Adds a python formatter (flutter#33797)

* Adds a python formatter

* Apply format

.style.yapf

@@ -0,0 +1,11 @@
+[style]
+based_on_style = yapf
+# Defined in https://github.com/google/yapf/blob/20d0c8f1774cf3843f4032f3e9ab02338bf98c75/yapf/yapflib/style.py#L326
+# Docs and full list of knobs:
+# https://github.com/google/yapf#knobs
+split_before_first_argument = true
+blank_line_before_module_docstring = true
+# dedent_closing_brackets is required by coalesce_brackets
+dedent_closing_brackets = true
+coalesce_brackets = true
+each_dict_entry_on_separate_line = false

DEPS

@@ -173,6 +173,9 @@ deps = {
   'src/third_party/boringssl':
    Var('github_git') + '/dart-lang/boringssl_gen.git' + '@' + Var('dart_boringssl_gen_rev'),
 
+  'src/third_party/yapf':
+  Var('github_git') + '/google/yapf' + '@' + '212c5b5ad8e172d2d914ae454c121c89cccbcb35',
+
   'src/third_party/boringssl/src':
    'https://boringssl.googlesource.com/boringssl.git' + '@' + Var('dart_boringssl_rev'),
 

build/android_artifacts.py

@@ -24,8 +24,13 @@ def cp_files(args):
 
 def main():
   parser = argparse.ArgumentParser()
-  parser.add_argument('-i', dest='input_pairs', nargs=2, action='append',
-      help='The input file and its destination.')
+  parser.add_argument(
+      '-i',
+      dest='input_pairs',
+      nargs=2,
+      action='append',
+      help='The input file and its destination.'
+  )
   cp_files(parser.parse_args())
   return 0
 

build/copy_info_plist.py

@@ -20,34 +20,60 @@
 import git_revision
 import os
 
-def GetClangVersion(bitcode) :
-  clang_executable = str(os.path.join("..", "..", "buildtools", "mac-x64", "clang", "bin", "clang++"))
+
+def GetClangVersion(bitcode):
+  clang_executable = str(
+      os.path.join(
+          "..", "..", "buildtools", "mac-x64", "clang", "bin", "clang++"
+      )
+  )
   if bitcode:
     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('--source', help='Path to Info.plist source template', type=str, required=True)
-  parser.add_argument('--destination', help='Path to destination Info.plist', type=str, required=True)
-  parser.add_argument('--bitcode', help='Built with bitcode', action='store_true')
-  parser.add_argument('--minversion', help='Minimum device OS version like "9.0"', type=str)
+  parser.add_argument(
+      '--source',
+      help='Path to Info.plist source template',
+      type=str,
+      required=True
+  )
+  parser.add_argument(
+      '--destination',
+      help='Path to destination Info.plist',
+      type=str,
+      required=True
+  )
+  parser.add_argument(
+      '--bitcode', help='Built with bitcode', action='store_true'
+  )
+  parser.add_argument(
+      '--minversion', help='Minimum device OS version like "9.0"', type=str
+  )
 
   args = parser.parse_args()
 
   text = open(args.source).read()
   engine_path = os.path.join(os.getcwd(), "..", "..", "flutter")
   revision = git_revision.GetRepositoryVersion(engine_path)
-  bitcode = args.bitcode is not None;
+  bitcode = args.bitcode is not None
   clang_version = GetClangVersion(bitcode)
-  text = text.format(revision = revision, clang_version = clang_version, min_version = args.minversion)
+  text = text.format(
+      revision=revision,
+      clang_version=clang_version,
+      min_version=args.minversion
+  )
 
   with open(args.destination, "w") as outfile:
     outfile.write(text)
 
+
 if __name__ == "__main__":
   main()

build/dart/tools/dart_package_name.py

@@ -10,11 +10,13 @@
 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 main(pubspec_file):
   source_file = open(pubspec_file, "r")
   for line in source_file:
@@ -25,15 +27,19 @@ def main(pubspec_file):
   # Couldn't find it.
   return -1
 
+
 if __name__ == '__main__':
   parser = argparse.ArgumentParser(
       description="This script outputs the package name specified in the"
-                  "pubspec.yaml")
-  parser.add_argument("--pubspec",
-                      dest="pubspec_file",
-                      metavar="<pubspec-file>",
-                      type=str,
-                      required=True,
-                      help="Path to pubspec file")
+      "pubspec.yaml"
+  )
+  parser.add_argument(
+      "--pubspec",
+      dest="pubspec_file",
+      metavar="<pubspec-file>",
+      type=str,
+      required=True,
+      help="Path to pubspec file"
+  )
   args = parser.parse_args()
   sys.exit(main(args.pubspec_file))

build/dart/tools/dart_pkg.py

@@ -16,8 +16,10 @@
 
 USE_LINKS = sys.platform != "win32"
 
-DART_ANALYZE = os.path.join(os.path.dirname(os.path.abspath(__file__)),
-                            "dart_analyze.py")
+DART_ANALYZE = os.path.join(
+    os.path.dirname(os.path.abspath(__file__)), "dart_analyze.py"
+)
+
 
 def dart_filter(path):
   if os.path.isdir(path):
@@ -142,7 +144,7 @@ def remove_broken_symlinks(root_dir):
 
 
 def analyze_entrypoints(dart_sdk, package_root, entrypoints):
-  cmd = [ "python", DART_ANALYZE ]
+  cmd = ["python", DART_ANALYZE]
   cmd.append("--dart-sdk")
   cmd.append(dart_sdk)
   cmd.append("--entrypoints")
@@ -161,60 +163,84 @@ def analyze_entrypoints(dart_sdk, package_root, entrypoints):
 
 def main():
   parser = argparse.ArgumentParser(description='Generate a dart-pkg')
-  parser.add_argument('--dart-sdk',
-                      action='store',
-                      metavar='dart_sdk',
-                      help='Path to the Dart SDK.')
-  parser.add_argument('--package-name',
-                      action='store',
-                      metavar='package_name',
-                      help='Name of package',
-                      required=True)
-  parser.add_argument('--pkg-directory',
-                      metavar='pkg_directory',
-                      help='Directory where dart_pkg should go',
-                      required=True)
-  parser.add_argument('--package-root',
-                      metavar='package_root',
-                      help='packages/ directory',
-                      required=True)
-  parser.add_argument('--stamp-file',
-                      metavar='stamp_file',
-                      help='timestamp file',
-                      required=True)
-  parser.add_argument('--entries-file',
-                      metavar='entries_file',
-                      help='script entries file',
-                      required=True)
-  parser.add_argument('--package-sources',
-                      metavar='package_sources',
-                      help='Package sources',
-                      nargs='+')
-  parser.add_argument('--package-entrypoints',
-                      metavar='package_entrypoints',
-                      help='Package entry points for analyzer',
-                      nargs='*',
-                      default=[])
-  parser.add_argument('--sdk-ext-directories',
-                      metavar='sdk_ext_directories',
-                      help='Directory containing .dart sources',
-                      nargs='*',
-                      default=[])
-  parser.add_argument('--sdk-ext-files',
-                      metavar='sdk_ext_files',
-                      help='List of .dart files that are part of sdk_ext.',
-                      nargs='*',
-                      default=[])
-  parser.add_argument('--sdk-ext-mappings',
-                      metavar='sdk_ext_mappings',
-                      help='Mappings for SDK extension libraries.',
-                      nargs='*',
-                      default=[])
-  parser.add_argument('--read_only',
-                      action='store_true',
-                      dest='read_only',
-                      help='Package is a read only package.',
-                      default=False)
+  parser.add_argument(
+      '--dart-sdk',
+      action='store',
+      metavar='dart_sdk',
+      help='Path to the Dart SDK.'
+  )
+  parser.add_argument(
+      '--package-name',
+      action='store',
+      metavar='package_name',
+      help='Name of package',
+      required=True
+  )
+  parser.add_argument(
+      '--pkg-directory',
+      metavar='pkg_directory',
+      help='Directory where dart_pkg should go',
+      required=True
+  )
+  parser.add_argument(
+      '--package-root',
+      metavar='package_root',
+      help='packages/ directory',
+      required=True
+  )
+  parser.add_argument(
+      '--stamp-file',
+      metavar='stamp_file',
+      help='timestamp file',
+      required=True
+  )
+  parser.add_argument(
+      '--entries-file',
+      metavar='entries_file',
+      help='script entries file',
+      required=True
+  )
+  parser.add_argument(
+      '--package-sources',
+      metavar='package_sources',
+      help='Package sources',
+      nargs='+'
+  )
+  parser.add_argument(
+      '--package-entrypoints',
+      metavar='package_entrypoints',
+      help='Package entry points for analyzer',
+      nargs='*',
+      default=[]
+  )
+  parser.add_argument(
+      '--sdk-ext-directories',
+      metavar='sdk_ext_directories',
+      help='Directory containing .dart sources',
+      nargs='*',
+      default=[]
+  )
+  parser.add_argument(
+      '--sdk-ext-files',
+      metavar='sdk_ext_files',
+      help='List of .dart files that are part of sdk_ext.',
+      nargs='*',
+      default=[]
+  )
+  parser.add_argument(
+      '--sdk-ext-mappings',
+      metavar='sdk_ext_mappings',
+      help='Mappings for SDK extension libraries.',
+      nargs='*',
+      default=[]
+  )
+  parser.add_argument(
+      '--read_only',
+      action='store_true',
+      dest='read_only',
+      help='Package is a read only package.',
+      default=False
+  )
   args = parser.parse_args()
 
   # We must have a pubspec.yaml.
@@ -233,14 +259,16 @@ def main():
   sdkext_path = os.path.join(lib_path, '_sdkext')
   if mappings:
     with open(sdkext_path, 'w') as stream:
-      json.dump(mappings, stream, sort_keys=True,
-                indent=2, separators=(',', ': '))
+      json.dump(
+          mappings, stream, sort_keys=True, indent=2, separators=(',', ': ')
+      )
   else:
     remove_if_exists(sdkext_path)
 
   # Copy or symlink package sources into pkg directory.
-  common_source_prefix = os.path.dirname(os.path.commonprefix(
-      args.package_sources))
+  common_source_prefix = os.path.dirname(
+      os.path.commonprefix(args.package_sources)
+  )
   for source in args.package_sources:
     relative_source = os.path.relpath(source, common_source_prefix)
     target = os.path.join(target_dir, relative_source)
@@ -263,8 +291,9 @@ def main():
       target = os.path.join(sdk_ext_dir, relative_source)
       copy_or_link(source, target)
 
-  common_source_prefix = os.path.dirname(os.path.commonprefix(
-      args.sdk_ext_files))
+  common_source_prefix = os.path.dirname(
+      os.path.commonprefix(args.sdk_ext_files)
+  )
   for source in args.sdk_ext_files:
     relative_source = os.path.relpath(source, common_source_prefix)
     target = os.path.join(sdk_ext_dir, relative_source)
@@ -293,5 +322,6 @@ def main():
 
   return 0
 
+
 if __name__ == '__main__':
   sys.exit(main())