Fix pylint for the main package

core/.flake8

@@ -1,4 +1,5 @@
 [flake8]
+import-order-style=google
 exclude =
   __pycache__,
   .git,

core/google/__init__.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+"""Google namespace package."""
+
 try:
     import pkg_resources
     pkg_resources.declare_namespace(__name__)

core/google/cloud/__init__.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+"""Google Cloud namespace package."""
+
 try:
     import pkg_resources
     pkg_resources.declare_namespace(__name__)

core/google/cloud/_helpers.py

@@ -17,7 +17,6 @@
 This module is not part of the public API surface.
 """
 
-# Avoid the grpc and google.cloud.grpc collision.
 from __future__ import absolute_import
 
 import calendar
@@ -32,6 +31,8 @@
 import google_auth_httplib2
 
 try:
+    # pylint: disable=ungrouped-imports
+    # We must import google.auth.transport.grpc within this try: catch.
     import grpc
     import google.auth.transport.grpc
 except ImportError:  # pragma: NO COVER
@@ -104,7 +105,7 @@ def top(self):
         :rtype: object
         :returns: the top-most item, or None if the stack is empty.
         """
-        if len(self._stack) > 0:
+        if self._stack:
             return self._stack[-1]
 
 

core/google/cloud/_http.py

@@ -279,7 +279,9 @@ def api_request(self, method, path, query_params=None,
             can allow custom behavior, for example, to defer an HTTP request
             and complete initialization of the object at a later time.
 
-        :raises: Exception if the response code is not 200 OK.
+        :raises ~google.cloud.exceptions.GoogleCloudError: if the response code
+            is not 200 OK.
+        :raises TypeError: if the response content type is not JSON.
         :rtype: dict or str
         :returns: The API response payload, either as a raw string or
                   a dictionary if the response is valid JSON.

core/google/cloud/_testing.py

@@ -14,17 +14,15 @@
 
 """Shared testing utilities."""
 
-
-# Avoid the grpc and google.cloud.grpc collision.
 from __future__ import absolute_import
 
 
 class _Monkey(object):
-    # context-manager for replacing module names in the scope of a test.
+    """Context-manager for replacing module names in the scope of a test."""
 
     def __init__(self, module, **kw):
         self.module = module
-        if len(kw) == 0:  # pragma: NO COVER
+        if not kw:  # pragma: NO COVER
             raise ValueError('_Monkey was used with nothing to monkey-patch')
         self.to_restore = {key: getattr(module, key) for key in kw}
         for key, value in kw.items():
@@ -68,8 +66,12 @@ def _tempdir_mgr():
     return _tempdir_mgr
 
 
+# pylint: disable=invalid-name
+# Retain _tempdir as a constant for backwards compatibility despite
+# being an invalid name.
 _tempdir = _tempdir_maker()
 del _tempdir_maker
+# pylint: enable=invalid-name
 
 
 class _GAXBaseAPI(object):
@@ -79,7 +81,8 @@ class _GAXBaseAPI(object):
     def __init__(self, **kw):
         self.__dict__.update(kw)
 
-    def _make_grpc_error(self, status_code, trailing=None):
+    @staticmethod
+    def _make_grpc_error(status_code, trailing=None):
         from grpc._channel import _RPCState
         from google.cloud.exceptions import GrpcRendezvous
 
@@ -111,6 +114,7 @@ def __init__(self, *pages, **kwargs):
         self.page_token = kwargs.get('page_token')
 
     def next(self):
+        """Iterate to the next page."""
         import six
         return six.next(self._pages)
 

core/google/cloud/client.py

@@ -64,7 +64,7 @@ def from_service_account_json(cls, json_credentials_path, *args, **kwargs):
 
         :rtype: :class:`_ClientFactoryMixin`
         :returns: The client created with the retrieved JSON credentials.
-        :raises: :class:`TypeError` if there is a conflict with the kwargs
+        :raises TypeError: if there is a conflict with the kwargs
                  and the credentials created by the factory.
         """
         if 'credentials' in kwargs:

core/google/cloud/future/operation.py

@@ -34,7 +34,7 @@ class Operation(base.PollingFuture):
             initial operation.
         refresh (Callable[[], Operation]): A callable that returns the
             latest state of the operation.
-        cancel (Callable[[], None]), A callable that tries to cancel
+        cancel (Callable[[], None]): A callable that tries to cancel
             the operation.
         result_type (type): The protobuf type for the operation's result.
         metadata_type (type): The protobuf type for the operation's

core/google/cloud/iam.py

@@ -226,14 +226,14 @@ def to_api_repr(self):
         if self.version is not None:
             resource['version'] = self.version
 
-        if len(self._bindings) > 0:
+        if self._bindings:
             bindings = resource['bindings'] = []
             for role, members in sorted(self._bindings.items()):
-                if len(members) > 0:
+                if members:
                     bindings.append(
                         {'role': role, 'members': sorted(set(members))})
 
-            if len(bindings) == 0:
+            if not bindings:
                 del resource['bindings']
 
         return resource

core/google/cloud/iterator.py

@@ -242,7 +242,8 @@ def _page_iter(self, increment):
                           results per page while an items iterator will want
                           to increment per item.
 
-        Yields :class:`Page` instances.
+        :rtype: :class:`Page`
+        :returns: pages
         """
         page = self._next_page()
         while page is not None:
@@ -387,6 +388,8 @@ def _get_next_page_response(self):
 
         :rtype: dict
         :returns: The parsed JSON response of the next page's contents.
+
+        :raises ValueError: If the HTTP method is not ``GET`` or ``POST``.
         """
         params = self._get_query_params()
         if self._HTTP_METHOD == 'GET':

core/google/cloud/operation.py

@@ -50,7 +50,7 @@ def register_type(klass, type_url=None):
     :param type_url: (Optional) URL naming the type. If not provided,
                      infers the URL from the type descriptor.
 
-    :raises: ValueError if a registration already exists for the URL.
+    :raises ValueError: if a registration already exists for the URL.
     """
     if type_url is None:
         type_url = _compute_type_url(klass)
@@ -258,7 +258,7 @@ def poll(self):
 
         :rtype: bool
         :returns: A boolean indicating if the current operation has completed.
-        :raises: :class:`~exceptions.ValueError` if the operation
+        :raises ValueError: if the operation
                  has already completed.
         """
         if self.complete:

core/nox.py

@@ -50,7 +50,8 @@ def lint(session):
     serious code quality issues.
     """
     session.interpreter = 'python3.6'
-    session.install('flake8', 'pylint', 'gcp-devrel-py-tools')
+    session.install(
+        'flake8', 'flake8-import-order', 'pylint', 'gcp-devrel-py-tools')
     session.install('.')
     session.run('flake8', 'google/cloud/core')
     session.run(