Use a python script to define Pylint config rather than an ini file (#69)

2 files changed, 254 insertions, 0 deletions

diff --git a/scripts/.gitignore b/scripts/.gitignore
new file mode 100644
index 0000000..3596d32
--- /dev/null
+++ b/scripts/.gitignore
@@ -0,0 +1,3 @@
+# Generated files
+pylintrc
+pylintrc.test
diff --git a/scripts/run_pylint.py b/scripts/run_pylint.py
new file mode 100644
index 0000000..ed994ff
--- /dev/null
+++ b/scripts/run_pylint.py
@@ -0,0 +1,251 @@
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""This script runs Pylint on the specified source.
+
+Before running Pylint, it generates a Pylint configuration on
+the fly based on programmatic defaults.
+"""
+
+from __future__ import print_function
+
+import collections
+import copy
+import io
+import os
+import subprocess
+import sys
+
+import six
+
+
+_SCRIPTS_DIR = os.path.abspath(os.path.dirname(__file__))
+PRODUCTION_RC = os.path.join(_SCRIPTS_DIR, 'pylintrc')
+TEST_RC = os.path.join(_SCRIPTS_DIR, 'pylintrc.test')
+
+_PRODUCTION_RC_ADDITIONS = {
+    'MESSAGES CONTROL': {
+        'disable': [
+            'I',
+            'import-error',
+            'no-member',
+            'protected-access',
+            'redefined-variable-type',
+            'similarities',
+        ],
+    },
+}
+_PRODUCTION_RC_REPLACEMENTS = {
+    'MASTER': {
+        'ignore': ['CVS', '.git', '.cache', '.tox', '.nox'],
+        'load-plugins': 'pylint.extensions.check_docs',
+    },
+    'REPORTS': {
+        'reports': 'no',
+    },
+    'BASIC': {
+        'method-rgx': '[a-z_][a-z0-9_]{2,40}$',
+        'function-rgx': '[a-z_][a-z0-9_]{2,40}$',
+    },
+    'TYPECHECK': {
+        'ignored-modules': ['six', 'google.protobuf'],
+    },
+    'DESIGN': {
+        'min-public-methods': '0',
+        'max-args': '10',
+        'max-attributes': '15',
+    },
+}
+_TEST_RC_ADDITIONS = copy.deepcopy(_PRODUCTION_RC_ADDITIONS)
+_TEST_RC_ADDITIONS['MESSAGES CONTROL']['disable'].extend([
+    'missing-docstring',
+    'no-self-use',
+    'redefined-outer-name',
+    'unused-argument',
+])
+_TEST_RC_REPLACEMENTS = copy.deepcopy(_PRODUCTION_RC_REPLACEMENTS)
+_TEST_RC_REPLACEMENTS.setdefault('BASIC', {})
+_TEST_RC_REPLACEMENTS['BASIC'].update({
+    'good-names': ['i', 'j', 'k', 'ex', 'Run', '_', 'fh'],
+    'method-rgx': '[a-z_][a-z0-9_]{2,80}$',
+    'function-rgx': '[a-z_][a-z0-9_]{2,80}$',
+})
+IGNORED_FILES = ()
+
+_ERROR_TEMPLATE = 'Pylint failed on {} with status {:d}.'
+_LINT_FILESET_MSG = (
+    'Keyword arguments rc_filename and description are both '
+    'required. No other keyword arguments are allowed.')
+
+
+def get_default_config():
+    """Get the default Pylint configuration.
+
+    .. note::
+
+        The output of this function varies based on the current version of
+        Pylint installed.
+
+    Returns:
+        str: The default Pylint configuration.
+    """
+    # Swallow STDERR if it says
+    # "No config file found, using default configuration"
+    result = subprocess.check_output(['pylint', '--generate-rcfile'],
+                                     stderr=subprocess.PIPE)
+    # On Python 3, this returns bytes (from STDOUT), so we
+    # convert to a string.
+    return result.decode('utf-8')
+
+
+def read_config(contents):
+    """Reads pylintrc config into native ConfigParser object.
+
+    Args:
+        contents (str): The contents of the file containing the INI config.
+
+    Returns
+        ConfigParser.ConfigParser: The parsed configuration.
+    """
+    file_obj = io.StringIO(contents)
+    config = six.moves.configparser.ConfigParser()
+    config.readfp(file_obj)
+    return config
+
+
+def _transform_opt(opt_val):
+    """Transform a config option value to a string.
+
+    If already a string, do nothing. If an iterable, then
+    combine into a string by joining on ",".
+
+    Args:
+        opt_val (Union[str, list]): A config option's value.
+
+    Returns:
+        str: The option value converted to a string.
+    """
+    if isinstance(opt_val, (list, tuple)):
+        return ','.join(opt_val)
+    else:
+        return opt_val
+
+
+def lint_fileset(*dirnames, **kwargs):
+    """Lints a group of files using a given rcfile.
+
+    Keyword arguments are
+
+    * ``rc_filename`` (``str``): The name of the Pylint config RC file.
+    * ``description`` (``str``): A description of the files and configuration
+                                 currently being run.
+
+    Args:
+        dirnames (tuple): Directories to run Pylint in.
+        kwargs: The keyword arguments. The only keyword arguments
+            are ``rc_filename`` and ``description`` and both
+            are required.
+
+    Raises:
+        KeyError: If the wrong keyword arguments are used.
+    """
+    try:
+        rc_filename = kwargs['rc_filename']
+        description = kwargs['description']
+        if len(kwargs) != 2:
+            raise KeyError
+    except KeyError:
+        raise KeyError(_LINT_FILESET_MSG)
+
+    pylint_shell_command = ['pylint', '--rcfile', rc_filename]
+    pylint_shell_command.extend(dirnames)
+    status_code = subprocess.call(pylint_shell_command)
+    if status_code != 0:
+        error_message = _ERROR_TEMPLATE.format(description, status_code)
+        print(error_message, file=sys.stderr)
+        sys.exit(status_code)
+
+
+def make_rc(base_cfg, target_filename,
+            additions=None, replacements=None):
+    """Combines a base rc and additions into single file.
+
+    Args:
+        base_cfg (ConfigParser.ConfigParser): The configuration we are
+            merging into.
+        target_filename (str): The filename where the new configuration
+            will be saved.
+        additions (dict): (Optional) The values added to the configuration.
+        replacements (dict): (Optional) The wholesale replacements for
+            the new configuration.
+
+    Raises:
+        KeyError: if one of the additions or replacements does not
+            already exist in the current config.
+    """
+    # Set-up the mutable default values.
+    if additions is None:
+        additions = {}
+    if replacements is None:
+        replacements = {}
+
+    # Create fresh config, which must extend the base one.
+    new_cfg = six.moves.configparser.ConfigParser()
+    # pylint: disable=protected-access
+    new_cfg._sections = copy.deepcopy(base_cfg._sections)
+    new_sections = new_cfg._sections
+    # pylint: enable=protected-access
+
+    for section, opts in additions.items():
+        curr_section = new_sections.setdefault(
+            section, collections.OrderedDict())
+        for opt, opt_val in opts.items():
+            curr_val = curr_section.get(opt)
+            if curr_val is None:
+                raise KeyError('Expected to be adding to existing option.')
+            curr_val = curr_val.rstrip(',')
+            opt_val = _transform_opt(opt_val)
+            curr_section[opt] = '%s, %s' % (curr_val, opt_val)
+
+    for section, opts in replacements.items():
+        curr_section = new_sections.setdefault(
+            section, collections.OrderedDict())
+        for opt, opt_val in opts.items():
+            curr_val = curr_section.get(opt)
+            if curr_val is None:
+                raise KeyError('Expected to be replacing existing option.')
+            opt_val = _transform_opt(opt_val)
+            curr_section[opt] = '%s' % (opt_val,)
+
+    with open(target_filename, 'w') as file_obj:
+        new_cfg.write(file_obj)
+
+
+def main():
+    """Script entry point. Lints both sets of files."""
+    default_config = read_config(get_default_config())
+    make_rc(default_config, PRODUCTION_RC,
+            additions=_PRODUCTION_RC_ADDITIONS,
+            replacements=_PRODUCTION_RC_REPLACEMENTS)
+    make_rc(default_config, TEST_RC,
+            additions=_TEST_RC_ADDITIONS,
+            replacements=_TEST_RC_REPLACEMENTS)
+    lint_fileset('google', rc_filename=PRODUCTION_RC,
+                 description='Library')
+    lint_fileset('tests', 'system_tests', rc_filename=TEST_RC,
+                 description='Test')
+
+
+if __name__ == '__main__':
+    main()