Fix python linter errors and add linter checks to CI

Internal CI systems and the new GitHub CI system were out of sync,
with the external system not doing any linting.  Further, the internal
system was using an internal-only linter for Python.

This creates a script for Python linting based on the open-source
pylint tool, checks in the Google Style Guide's pylintrc file, creates
a custom action for linting and adds it to the existing workflows,
fixes pre-existing linter errors in Python scripts, and updates pylint
overrides.

b/190743862

Change-Id: Iff1f5d4690b32479af777ded0834c31c2161bd10

.github/workflows/README.md

@@ -1,6 +1,10 @@
 # GitHub Actions CI
 
 ## Actions
+ - `custom-actions/lint-packager`:
+   Lints Shaka Packager.  You must pass `fetch-depth: 2` to `actions/checkout`
+   in order to provide enough history for the linter to tell which files have
+   changed.
  - `custom-actions/build-packager`:
    Builds Shaka Packager.  Leaves build artifacts in the "artifacts" folder.
    Requires OS-dependent and build-dependent inputs.

.github/workflows/build_and_test.yaml

@@ -16,7 +16,26 @@ on:
         required: False
 
 jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+        with:
+          path: src
+          ref: ${{ github.event.inputs.ref || github.ref }}
+          # This makes the merge base available for the C++ linter, so that it
+          # can tell which files have changed.
+          fetch-depth: 2
+
+      - name: Lint
+        uses: ./src/.github/workflows/custom-actions/lint-packager
+
   build_and_test:
+    # Doesn't really "need" it, but let's not waste time on an expensive matrix
+    # build step just to cancel it because of a linter error.
+    needs: lint
     strategy:
       matrix:
         os: ["ubuntu-latest", "macos-latest", "windows-latest"]

.github/workflows/custom-actions/lint-packager/action.yaml

@@ -0,0 +1,33 @@
+name: Lint Shaka Packager
+
+description: |
+  A reusable action to lint Shaka Packager source.
+  When checking out source, you must use 'fetch-depth: 2' in actions/checkout,
+  or else the linter won't have another revision to compare to.
+
+runs:
+  using: composite
+  steps:
+    - name: Lint
+      shell: bash
+      run: |
+        cd src/
+        echo "::group::Installing git-clang-format"
+        wget https://raw.githubusercontent.com/llvm-mirror/clang/master/tools/clang-format/git-clang-format
+        sudo install -m 755 git-clang-format /usr/local/bin/git-clang-format
+        rm git-clang-format
+        echo "::endgroup::"
+        echo "::group::Check clang-format for C++ sources"
+        # NOTE: --binary forces use of global clang-format (which works) instead
+        # of depot_tools clang-format (which doesn't).
+        # NOTE: Must use base.sha instead of base.ref, since we don't have
+        # access to the branch name that base.ref would give us.
+        # NOTE: Must also use fetch-depth: 2 in actions/checkout to have access
+        # to the base ref for comparison.
+        packager/tools/git/check_formatting.py \
+            --binary /usr/bin/clang-format \
+            ${{ github.event.pull_request.base.sha || 'HEAD^' }}
+        echo "::endgroup::"
+        echo "::group::Check pylint for Python sources"
+        packager/tools/git/check_pylint.py
+        echo "::endgroup::"

.github/workflows/github_release.yaml

@@ -91,8 +91,25 @@ jobs:
           body_path: RELEASE_NOTES.md
           draft: true
 
+  lint:
+    needs: setup
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+        with:
+          path: src
+          ref: ${{ needs.setup.outputs.tag }}
+          # This makes the merge base available for the C++ linter, so that it
+          # can tell which files have changed.
+          fetch-depth: 2
+
+      - name: Lint
+        uses: ./src/.github/workflows/custom-actions/lint-packager
+
   build_and_test:
-    needs: [setup, draft_release]
+    needs: [setup, lint, draft_release]
     strategy:
       matrix:
         os: ["ubuntu-latest", "macos-latest", "windows-latest"]

gyp_packager.py

@@ -39,7 +39,7 @@ checkout_dir = os.path.dirname(os.path.realpath(__file__))
 src_dir = os.path.join(checkout_dir, 'packager')
 
 # Workaround the dynamic path.
-# pylint: disable=g-import-not-at-top,g-bad-import-order
+# pylint: disable=wrong-import-position
 
 sys.path.insert(0, os.path.join(src_dir, 'build'))
 import gyp_helper

kokoro/windows/build.bat

@@ -1,6 +1,7 @@
 :: Copyright 2017 Google Inc. All Rights Reserved.
 set ROOTDIR=%cd%
 set PACKAGERDIR=%ROOTDIR%\git\src
+set PATH=c:\Python35;%PATH%
 
 set GYP_DEFINES="target_arch=%PLATFORM%"
 if "%PLATFORM%"=="x64" (

packager/app/test/packager_test.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Copyright 2014 Google Inc. All Rights Reserved.
 #
@@ -131,23 +131,19 @@ class DiffFilesPolicy(object):
       actual_file = os.path.join(out_dir, diff_file)
       expected_file = os.path.join(gold_dir, diff_file)
 
-      output, error = self._GitDiff(expected_file, actual_file)
+      output = self._GitDiff(expected_file, actual_file)
 
       # If this is an MP4 file, get a better looking diff.
-      if ((output or error) and
+      if (output and
           os.path.splitext(actual_file)[1] in {'.mp4', '.m4s'}):
-        new_output, new_error = self._Mp4Diff(
+        new_output = self._Mp4Diff(
             out_dir, expected_file, actual_file)
 
         output = new_output or output
-        error = new_error or error
 
       if output:
         failure_messages += [output.decode('utf8')]
 
-      if error:
-        failure_messages += [error.decode('utf8')]
-
     if self._exact:
       for diff_file in self._allowed_diff_files:
         if diff_file not in diff.diff_files:
@@ -166,8 +162,7 @@ class DiffFilesPolicy(object):
         file_a,
         file_b
     ]
-    p = subprocess.Popen(cmd, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
-    return p.communicate()
+    return subprocess.check_output(cmd)
 
   def _Mp4Diff(self, out_dir, file_a, file_b):
     dump_a = os.path.join(out_dir, os.path.basename(file_a) + '.dump.expected')
@@ -262,7 +257,7 @@ def GetSegmentedExtension(base_extension):
 class PackagerAppTest(unittest.TestCase):
 
   def setUp(self):
-    super(PackagerAppTest, self).setUp()
+    super().setUp()
     self.packager = packager_app.PackagerApp()
     self.tmp_dir = tempfile.mkdtemp()
     self.test_data_dir = os.path.join(test_env.SRC_DIR, 'packager', 'media',
@@ -294,7 +289,7 @@ class PackagerAppTest(unittest.TestCase):
   def tearDown(self):
     if test_env.options.remove_temp_files_after_test:
       shutil.rmtree(self.tmp_dir)
-    super(PackagerAppTest, self).tearDown()
+    super().tearDown()
 
   def _GetStream(self,
                  descriptor,

packager/tools/git/check_pylint.py

@@ -0,0 +1,43 @@
+#!/usr/bin/python3
+"""Lints all Python sources in the repo, excluding third-party code."""
+
+import os
+import subprocess
+
+import pylint.lint
+
+def ShouldLintFile(path):
+  """Returns True if this path should be linted."""
+  excluded_folders = [
+      'third_party',
+      'protoc_wrapper',
+      'ycm_extra_conf',
+  ]
+
+  if (not path.endswith('.py') or
+      any(f in path for f in excluded_folders)):
+    return False
+
+  return True
+
+def GetPyFileList():
+  """Yield the paths of Python source files that should be linted."""
+  output = subprocess.check_output(['git', 'ls-files'], text=True)
+
+  for path in output.split('\n'):
+    if ShouldLintFile(path):
+      yield path
+
+def main():
+  """Lint Python source files.
+
+  Pylint will exit with a non-zero status if there are any failures."""
+  dir_name = os.path.dirname(__file__)
+  rc_path = os.path.join(dir_name, 'pylintrc')
+
+  py_files = list(GetPyFileList())
+  # Run will call sys.exit, so no explicit call to sys.exit is used here.
+  pylint.lint.Run(['--rcfile={}'.format(rc_path)] + py_files)
+
+if __name__ == '__main__':
+  main()

packager/tools/git/pylintrc

@@ -0,0 +1,441 @@
+# This Pylint rcfile contains a best-effort configuration to uphold the
+# best-practices and style described in the Google Python style guide:
+#   https://google.github.io/styleguide/pyguide.html
+#
+# Its canonical open-source location is:
+#   https://google.github.io/styleguide/pylintrc
+
+[MASTER]
+
+# Files or directories to be skipped. They should be base names, not paths.
+ignore=third_party
+
+# Files or directories matching the regex patterns are skipped. The regex
+# matches against base names, not paths.
+ignore-patterns=
+
+# Pickle collected data for later comparisons.
+persistent=no
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+# Use multiple processes to speed up Pylint.
+jobs=4
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+
+[MESSAGES CONTROL]
+
+# Only show warnings with the listed confidence levels. Leave empty to show
+# all. Valid levels: HIGH, INFERENCE, INFERENCE_FAILURE, UNDEFINED
+confidence=
+
+# 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 (only on the command line, not in the configuration file where
+# it should appear only once). See also the "--disable" option for examples.
+#enable=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once).You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use"--disable=all --enable=classes
+# --disable=W"
+disable=abstract-method,
+        apply-builtin,
+        arguments-differ,
+        attribute-defined-outside-init,
+        backtick,
+        bad-option-value,
+        basestring-builtin,
+        buffer-builtin,
+        c-extension-no-member,
+        consider-using-enumerate,
+        cmp-builtin,
+        cmp-method,
+        coerce-builtin,
+        coerce-method,
+        delslice-method,
+        div-method,
+        duplicate-code,
+        eq-without-hash,
+        execfile-builtin,
+        file-builtin,
+        filter-builtin-not-iterating,
+        fixme,
+        getslice-method,
+        global-statement,
+        hex-method,
+        idiv-method,
+        implicit-str-concat-in-sequence,
+        import-error,
+        import-self,
+        import-star-module-level,
+        inconsistent-return-statements,
+        input-builtin,
+        intern-builtin,
+        invalid-str-codec,
+        locally-disabled,
+        long-builtin,
+        long-suffix,
+        map-builtin-not-iterating,
+        misplaced-comparison-constant,
+        missing-function-docstring,
+        metaclass-assignment,
+        next-method-called,
+        next-method-defined,
+        no-absolute-import,
+        no-else-break,
+        no-else-continue,
+        no-else-raise,
+        no-else-return,
+        no-init,  # added
+        no-member,
+        no-name-in-module,
+        no-self-use,
+        nonzero-method,
+        oct-method,
+        old-division,
+        old-ne-operator,
+        old-octal-literal,
+        old-raise-syntax,
+        parameter-unpacking,
+        print-statement,
+        raising-string,
+        range-builtin-not-iterating,
+        raw_input-builtin,
+        rdiv-method,
+        reduce-builtin,
+        relative-import,
+        reload-builtin,
+        round-builtin,
+        setslice-method,
+        signature-differs,
+        standarderror-builtin,
+        suppressed-message,
+        sys-max-int,
+        too-few-public-methods,
+        too-many-ancestors,
+        too-many-arguments,
+        too-many-boolean-expressions,
+        too-many-branches,
+        too-many-instance-attributes,
+        too-many-locals,
+        too-many-nested-blocks,
+        too-many-public-methods,
+        too-many-return-statements,
+        too-many-statements,
+        trailing-newlines,
+        unichr-builtin,
+        unicode-builtin,
+        unnecessary-pass,
+        unpacking-in-except,
+        useless-else-on-loop,
+        useless-object-inheritance,
+        useless-suppression,
+        using-cmp-argument,
+        wrong-import-order,
+        xrange-builtin,
+        zip-builtin-not-iterating,
+
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html. You can also give a reporter class, eg
+# mypackage.mymodule.MyReporterClass.
+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]". This option is deprecated
+# and it will be removed in Pylint 2.0.
+files-output=no
+
+# Tells whether to display a full report or only the messages
+reports=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)
+
+# Template used to display messages. This is a python new-style format string
+# used to format the message information. See doc for all details
+#msg-template=
+
+
+[BASIC]
+
+# Good variable names which should always be accepted, separated by a comma
+good-names=main,_
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Include a hint for the correct naming format with invalid-name
+include-naming-hint=no
+
+# List of decorators that produce properties, such as abc.abstractproperty. Add
+# to this list to register other decorators that produce valid properties.
+property-classes=abc.abstractproperty,cached_property.cached_property,cached_property.threaded_cached_property,cached_property.cached_property_with_ttl,cached_property.threaded_cached_property_with_ttl
+
+# Regular expression matching correct function names
+function-rgx=^(?:(?P<exempt>setUp|tearDown|setUpModule|tearDownModule)|(?P<camel_case>_?[A-Z][a-zA-Z0-9]*)|(?P<snake_case>_?[a-z][a-z0-9_]*))$
+
+# Regular expression matching correct variable names
+variable-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct constant names
+const-rgx=^(_?[A-Z][A-Z0-9_]*|__[a-z0-9_]+__|_?[a-z][a-z0-9_]*)$
+
+# Regular expression matching correct attribute names
+attr-rgx=^_{0,2}[a-z][a-z0-9_]*$
+
+# Regular expression matching correct argument names
+argument-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct class attribute names
+class-attribute-rgx=^(_?[A-Z][A-Z0-9_]*|__[a-z0-9_]+__|_?[a-z][a-z0-9_]*)$
+
+# Regular expression matching correct inline iteration names
+inlinevar-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct class names
+class-rgx=^_?[A-Z][a-zA-Z0-9]*$
+
+# Regular expression matching correct module names
+module-rgx=^(_?[a-z][a-z0-9_]*|__init__)$
+
+# Regular expression matching correct method names
+method-rgx=(?x)^(?:(?P<exempt>_[a-z0-9_]+__|runTest|setUp|tearDown|setUpTestCase|tearDownTestCase|setupSelf|tearDownClass|setUpClass|(test|assert)_*[A-Z0-9][a-zA-Z0-9_]*|next)|(?P<camel_case>_{0,2}[A-Z][a-zA-Z0-9_]*)|(?P<snake_case>_{0,2}[a-z][a-z0-9_]*))$
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=(__.*__|main|test.*|.*test|.*Test)$
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=10
+
+
+[TYPECHECK]
+
+# List of decorators that produce context managers, such as
+# contextlib.contextmanager. Add to this list to register other decorators that
+# produce valid context managers.
+contextmanager-decorators=contextlib.contextmanager,contextlib2.contextmanager
+
+# 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 module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis. It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=
+
+# List of class names for which member attributes should not be checked (useful
+# for classes with dynamically set attributes). This supports the use of
+# qualified names.
+ignored-classes=optparse.Values,thread._local,_thread._local
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+max-line-length=80
+
+# TODO(https://github.com/PyCQA/pylint/issues/3352): Direct pylint to exempt
+# lines made too long by directives to pytype.
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=(?x)(
+  ^\s*(\#\ )?<?https?://\S+>?$|
+  ^\s*(from\s+\S+\s+)?import\s+.+$)
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=yes
+
+# List of optional constructs for which whitespace checking is disabled. `dict-
+# separator` is used to allow tabulation in dicts, etc.: {1  : 1,\n222: 2}.
+# `trailing-comma` allows a space between comma and closing bracket: (a, ).
+# `empty-line` allows space-only lines.
+no-space-check=
+
+# Maximum number of lines in a module
+max-module-lines=99999
+
+# String used as indentation unit.  The internal Google style guide mandates 2
+# spaces.  Google's externaly-published style guide says 4, consistent with
+# PEP 8.  Here, we use 2 spaces, for conformity with many open-sourced Google
+# projects (like TensorFlow).
+indent-string='  '
+
+# Number of spaces of indent required inside a hanging  or continued line.
+indent-after-paren=4
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=TODO
+
+
+[STRING]
+
+# This flag controls whether inconsistent-quotes generates a warning when the
+# character used as a quote delimiter is used inconsistently within a module.
+check-quote-consistency=yes
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the name of dummy variables (i.e. expectedly
+# not used).
+dummy-variables-rgx=^\*{0,2}(_$|unused_|dummy_)
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,_cb
+
+# List of qualified module names which can have objects that can redefine
+# builtins.
+redefining-builtins-modules=six,six.moves,past.builtins,future.builtins,functools
+
+
+[LOGGING]
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format
+logging-modules=logging,absl.logging,tensorflow.io.logging
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+# Ignore imports when computing similarities.
+ignore-imports=no
+
+
+[SPELLING]
+
+# Spelling dictionary name. Available dictionaries: none. To make it working
+# install python-enchant package.
+spelling-dict=
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to indicated private dictionary in
+# --spelling-private-dict-file option instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=regsub,
+                   TERMIOS,
+                   Bastion,
+                   rexec,
+                   sets
+
+# 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=
+
+# Force import order to recognize a module as part of the standard
+# compatibility libraries.
+known-standard-library=
+
+# Force import order to recognize a module as part of a third party library.
+known-third-party=enchant, absl
+
+# Analyse import fallback blocks. This can be used to support both Python 2 and
+# 3 compatible code, which means that the block might have code that exists
+# only in one or another interpreter, leading to false positives when analysed.
+analyse-fallback-blocks=no
+
+
+[CLASSES]
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,
+                      __new__,
+                      setUp
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,
+                  _fields,
+                  _replace,
+                  _source,
+                  _make
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls,
+                            class_
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=StandardError,
+                       Exception,
+                       BaseException

packager/tools/pssh/pssh-box.py

@@ -7,6 +7,10 @@
 
 """A utility to parse and generate PSSH boxes."""
 
+# This file itself is considered an invalid module name because of the dash in
+# the filename: pssh-box.py
+# pylint: disable=invalid-name
+
 from __future__ import print_function
 
 import argparse
@@ -26,7 +30,8 @@ assert os.path.exists(_proto_path), (
 sys.path.insert(0, _proto_path)
 sys.path.insert(0, _widevine_proto_path)
 
-import widevine_pssh_data_pb2  # pylint: disable=g-import-not-at-top
+# pylint: disable=wrong-import-position
+import widevine_pssh_data_pb2
 
 COMMON_SYSTEM_ID = base64.b16decode('1077EFECC0B24D02ACE33C1E52E2FB4B')
 WIDEVINE_SYSTEM_ID = base64.b16decode('EDEF8BA979D64ACEA3C827DCD51D21ED')

packager/version/generate_version_string.py

@@ -11,30 +11,9 @@ from __future__ import print_function
 
 import subprocess
 
-# To support python version before 2.7, which does not have
-# subprocess.check_output.
-if 'check_output' not in dir(subprocess):
-
-  def check_output_implementation(*popenargs, **kwargs):
-    """Implement check_output if it is not available."""
-    if 'stdout' in kwargs:
-      raise ValueError('stdout argument not allowed, it will be overridden.')
-    process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
-    output, unused_err = process.communicate()
-    retcode = process.poll()
-    if retcode:
-      cmd = kwargs.get('args')
-      if cmd is None:
-        cmd = popenargs[0]
-      raise subprocess.CalledProcessError(retcode, cmd)
-    return output
-
-  subprocess.check_output = check_output_implementation
-
 if __name__ == '__main__':
   try:
-    version_tag = subprocess.check_output(
-        'git tag --points-at HEAD',
+    version_tag = subprocess.check_output('git tag --points-at HEAD',
         stderr=subprocess.STDOUT, shell=True).rstrip()
   except subprocess.CalledProcessError as e:
     # git tag --points-at is not supported in old versions of git. Just ignore
@@ -42,8 +21,7 @@ if __name__ == '__main__':
     version_tag = None
 
   try:
-    version_hash = subprocess.check_output(
-        'git rev-parse --short HEAD',
+    version_hash = subprocess.check_output('git rev-parse --short HEAD',
         stderr=subprocess.STDOUT, shell=True).rstrip()
   except subprocess.CalledProcessError as e:
     version_hash = 'unknown-version'