mypy: set no_implicit_optional

The current version of PEP-484 indicates that
type checkers should not allow implicit optional
parameters.

- https://www.python.org/dev/peps/pep-0484/#union-types
- python/mypy#9091

Change-Id: I49e5729a4d754934e861d4d0fd25fd8b2a80602e

cinder/backup/api.py

@@ -119,12 +119,12 @@ def delete(self,
 
     def get_all(self,
                 context: context.RequestContext,
-                search_opts: dict = None,
-                marker: str = None,
-                limit: int = None,
-                offset: int = None,
-                sort_keys: List[str] = None,
-                sort_dirs: List[str] = None) -> 'objects.BackupList':
+                search_opts: Optional[dict] = None,
+                marker: Optional[str] = None,
+                limit: Optional[int] = None,
+                offset: Optional[int] = None,
+                sort_keys: Optional[List[str]] = None,
+                sort_dirs: Optional[List[str]] = None) -> 'objects.BackupList':
         context.authorize(policy.GET_ALL_POLICY)
 
         search_opts = search_opts or {}
@@ -223,10 +223,10 @@ def create(self,
                volume_id: str,
                container: str,
                incremental: bool = False,
-               availability_zone: str = None,
+               availability_zone: Optional[str] = None,
                force: bool = False,
                snapshot_id: Optional[str] = None,
-               metadata: dict = None) -> 'objects.Backup':
+               metadata: Optional[dict] = None) -> 'objects.Backup':
         """Make the RPC call to create a volume backup."""
         volume = self.volume_api.get(context, volume_id)
         context.authorize(policy.CREATE_POLICY, target_obj=volume)
@@ -365,8 +365,8 @@ def create(self,
     def restore(self,
                 context: context.RequestContext,
                 backup_id: str,
-                volume_id: str = None,
-                name: str = None) -> dict:
+                volume_id: Optional[str] = None,
+                name: Optional[str] = None) -> dict:
         """Make the RPC call to restore a volume backup."""
         backup = self.get(context, backup_id)
         context.authorize(policy.RESTORE_POLICY, target_obj=backup)

cinder/coordination.py

@@ -21,7 +21,7 @@
 import os
 import re
 import sys
-from typing import Callable
+from typing import Callable, Optional  # noqa: H301
 import uuid
 
 import decorator
@@ -56,7 +56,7 @@ class Coordinator(object):
         meaningful prefix.
     """
 
-    def __init__(self, agent_id: str = None, prefix: str = ''):
+    def __init__(self, agent_id: Optional[str] = None, prefix: str = ''):
         self.coordinator = None
         self.agent_id = agent_id or str(uuid.uuid4())
         self.started = False

cinder/exception.py

@@ -22,7 +22,7 @@
 
 """
 
-from typing import Union
+from typing import Optional, Union  # noqa: H301
 
 from oslo_log import log as logging
 from oslo_versionedobjects import exception as obj_exc
@@ -72,7 +72,7 @@ class CinderException(Exception):
     headers: dict = {}
     safe = False
 
-    def __init__(self, message: Union[str, tuple] = None, **kwargs):
+    def __init__(self, message: Optional[Union[str, tuple]] = None, **kwargs):
         self.kwargs = kwargs
         self.kwargs['message'] = message
 

cinder/image/image_utils.py

@@ -183,10 +183,11 @@ def _get_qemu_convert_luks_cmd(src: str,
                                src_format: Optional[str] = None,
                                out_subformat: Optional[str] = None,
                                cache_mode: Optional[str] = None,
-                               prefix: tuple = None,
+                               prefix: Optional[tuple] = None,
                                cipher_spec: Optional[dict] = None,
                                passphrase_file: Optional[str] = None,
-                               src_passphrase_file: str = None) -> List[str]:
+                               src_passphrase_file: Optional[str] = None) \
+        -> List[str]:
 
     cmd = ['qemu-img', 'convert']
 
@@ -214,14 +215,15 @@ def _get_qemu_convert_luks_cmd(src: str,
 def _get_qemu_convert_cmd(src: str,
                           dest: str,
                           out_format: str,
-                          src_format: str = None,
-                          out_subformat: str = None,
-                          cache_mode: str = None,
-                          prefix: tuple = None,
-                          cipher_spec: dict = None,
-                          passphrase_file: str = None,
+                          src_format: Optional[str] = None,
+                          out_subformat: Optional[str] = None,
+                          cache_mode: Optional[str] = None,
+                          prefix: Optional[tuple] = None,
+                          cipher_spec: Optional[dict] = None,
+                          passphrase_file: Optional[str] = None,
                           compress: bool = False,
-                          src_passphrase_file: str = None) -> List[str]:
+                          src_passphrase_file: Optional[str] = None) \
+        -> List[str]:
 
     if src_passphrase_file is not None:
         if passphrase_file is None:
@@ -314,13 +316,13 @@ def _convert_image(prefix: tuple,
                    source: str,
                    dest: str,
                    out_format: str,
-                   out_subformat: str = None,
-                   src_format: str = None,
+                   out_subformat: Optional[str] = None,
+                   src_format: Optional[str] = None,
                    run_as_root: bool = True,
-                   cipher_spec: dict = None,
-                   passphrase_file: str = None,
+                   cipher_spec: Optional[dict] = None,
+                   passphrase_file: Optional[str] = None,
                    compress: bool = False,
-                   src_passphrase_file: str = None) -> None:
+                   src_passphrase_file: Optional[str] = None) -> None:
     """Convert image to other format.
 
     NOTE: If the qemu-img convert command fails and this function raises an
@@ -421,14 +423,14 @@ def _convert_image(prefix: tuple,
 def convert_image(source: str,
                   dest: str,
                   out_format: str,
-                  out_subformat: str = None,
-                  src_format: str = None,
+                  out_subformat: Optional[str] = None,
+                  src_format: Optional[str] = None,
                   run_as_root: bool = True,
                   throttle=None,
-                  cipher_spec: dict = None,
-                  passphrase_file: str = None,
+                  cipher_spec: Optional[dict] = None,
+                  passphrase_file: Optional[str] = None,
                   compress: bool = False,
-                  src_passphrase_file: str = None) -> None:
+                  src_passphrase_file: Optional[str] = None) -> None:
     if not throttle:
         throttle = throttling.Throttle.get_default()
     with throttle.subcommand(source, dest) as throttle_cmd:
@@ -447,7 +449,7 @@ def convert_image(source: str,
 def resize_image(source: str,
                  size: int,
                  run_as_root: bool = False,
-                 file_format: str = None) -> None:
+                 file_format: Optional[str] = None) -> None:
     """Changes the virtual size of the image."""
     cmd: Tuple[str, ...]
     if file_format:
@@ -805,7 +807,7 @@ def upload_volume(context: context.RequestContext,
                   volume_format: str = 'raw',
                   run_as_root: bool = True,
                   compress: bool = True,
-                  store_id: str = None,
+                  store_id: Optional[str] = None,
                   base_image_ref: Optional[str] = None) -> None:
     # NOTE: You probably want to use volume_utils.upload_volume(),
     # not this function.

cinder/scheduler/base_weight.py

@@ -29,8 +29,8 @@
 
 
 def normalize(weight_list: List[float],
-              minval: float = None,
-              maxval: float = None) -> Iterable[float]:
+              minval: Optional[float] = None,
+              maxval: Optional[float] = None) -> Iterable[float]:
     """Normalize the values in a list between 0 and 1.0.
 
     The normalization is made regarding the lower and upper values present in

cinder/scheduler/filter_scheduler.py

@@ -485,7 +485,8 @@ def _find_valid_backends(self,
 
     def _get_weighted_candidates_by_group_type(
             self, context: context.RequestContext, group_spec: dict,
-            group_filter_properties: dict = None) -> List[WeighedHost]:
+            group_filter_properties: Optional[dict] = None) \
+            -> List[WeighedHost]:
         """Finds backends that supports the group type.
 
         Returns a list of backends that meet the required specs,

cinder/scheduler/host_manager.py

@@ -72,7 +72,7 @@
 
 class ReadOnlyDict(abc.Mapping):
     """A read-only dict."""
-    def __init__(self, source: Union[dict, 'ReadOnlyDict'] = None):
+    def __init__(self, source: Optional[Union[dict, 'ReadOnlyDict']] = None):
         self.data: dict
         if source is not None:
             self.data = dict(source)

cinder/utils.py

@@ -234,7 +234,7 @@ def check_metadata_properties(
             raise exception.InvalidVolumeMetadataSize(reason=msg)
 
 
-def last_completed_audit_period(unit: str = None) -> \
+def last_completed_audit_period(unit: Optional[str] = None) -> \
         Tuple[Union[datetime.datetime, datetime.timedelta],
               Union[datetime.datetime, datetime.timedelta]]:
     """This method gives you the most recently *completed* audit period.
@@ -374,7 +374,9 @@ def monkey_patch() -> None:
                         decorator("%s.%s" % (module, key), func))
 
 
-def make_dev_path(dev: str, partition: str = None, base: str = '/dev') -> str:
+def make_dev_path(dev: str,
+                  partition: Optional[str] = None,
+                  base: str = '/dev') -> str:
     """Return a path to a particular device.
 
     >>> make_dev_path('xvdc')
@@ -434,7 +436,8 @@ def robust_file_write(directory: str, filename: str, data: str) -> None:
 
 
 @contextlib.contextmanager
-def temporary_chown(path: str, owner_uid: int = None) -> Iterator[None]:
+def temporary_chown(path: str,
+                    owner_uid: Optional[int] = None) -> Iterator[None]:
     """Temporarily chown a path.
 
     :params owner_uid: UID of temporary owner (defaults to current user)
@@ -493,7 +496,7 @@ def get_file_size(path: str) -> int:
 
 def _get_disk_of_partition(
         devpath: str,
-        st: os.stat_result = None) -> Tuple[str, os.stat_result]:
+        st: Optional[os.stat_result] = None) -> Tuple[str, os.stat_result]:
     """Gets a disk device path and status from partition path.
 
     Returns a disk device path from a partition device path, and stat for
@@ -558,7 +561,7 @@ def get_blkdev_major_minor(path: str,
 
 
 def check_string_length(value: str, name: str, min_length: int = 0,
-                        max_length: int = None,
+                        max_length: Optional[int] = None,
                         allow_all_spaces: bool = True) -> None:
     """Check the length of specified string.
 
@@ -684,7 +687,7 @@ def convert_str(text: Union[str, bytes]) -> str:
 
 
 def build_or_str(elements: Union[None, str, Iterable[str]],
-                 str_format: str = None) -> str:
+                 str_format: Optional[str] = None) -> str:
     """Builds a string of elements joined by 'or'.
 
     Will join strings with the 'or' word and if a str_format is provided it

cinder/volume/api.py

@@ -219,10 +219,10 @@ def create(self,
                name: Optional[str],
                description: Optional[str],
                snapshot: Optional[objects.Snapshot] = None,
-               image_id: str = None,
+               image_id: Optional[str] = None,
                volume_type: Optional[objects.VolumeType] = None,
                metadata: Optional[dict] = None,
-               availability_zone: str = None,
+               availability_zone: Optional[str] = None,
                source_volume: Optional[objects.Volume] = None,
                scheduler_hints=None,
                source_replica=None,
@@ -1154,7 +1154,7 @@ def _create_snapshot_in_db_options(
             name: str,
             description: str,
             cgsnapshot_id: str,
-            group_snapshot_id: str = None) -> Dict[str, Any]:
+            group_snapshot_id: Optional[str] = None) -> Dict[str, Any]:
         options = {'volume_id': volume['id'],
                    'cgsnapshot_id': cgsnapshot_id,
                    'group_snapshot_id': group_snapshot_id,
@@ -1175,7 +1175,7 @@ def create_snapshot(
             volume: objects.Volume,
             name: str,
             description: str,
-            metadata: Dict[str, Any] = None,
+            metadata: Optional[Dict[str, Any]] = None,
             cgsnapshot_id: Optional[str] = None,
             group_snapshot_id: Optional[str] = None,
             allow_in_use: bool = False) -> objects.Snapshot:
@@ -1192,7 +1192,7 @@ def create_snapshot_force(
             volume: objects.Volume,
             name: str,
             description: str,
-            metadata: Dict[str, Any] = None) -> objects.Snapshot:
+            metadata: Optional[Dict[str, Any]] = None) -> objects.Snapshot:
         result = self._create_snapshot(context, volume, name, description,
                                        True, metadata)
         LOG.info("Snapshot force create request issued successfully.",

cinder/volume/drivers/rbd.py

@@ -159,11 +159,11 @@ class RBDVolumeProxy(object):
     def __init__(self,
                  driver: 'RBDDriver',
                  name: str,
-                 pool: str = None,
-                 snapshot: str = None,
+                 pool: Optional[str] = None,
+                 snapshot: Optional[str] = None,
                  read_only: bool = False,
                  remote: Optional[Dict[str, str]] = None,
-                 timeout: int = None,
+                 timeout: Optional[int] = None,
                  client: 'rados.Rados' = None,
                  ioctx: 'rados.Ioctx' = None):
         self._close_conn = not (client and ioctx)
@@ -205,7 +205,9 @@ def __getattr__(self, attrib: str):
 
 class RADOSClient(object):
     """Context manager to simplify error handling for connecting to ceph."""
-    def __init__(self, driver: 'RBDDriver', pool: str = None) -> None:
+    def __init__(self,
+                 driver: 'RBDDriver',
+                 pool: Optional[str] = None) -> None:
         self.driver = driver
         self.cluster, self.ioctx = driver._connect_to_rados(pool)
 
@@ -246,7 +248,7 @@ class RBDDriver(driver.CloneableImageVD, driver.MigrateVD,
     STORAGE_PROTOCOL = 'ceph'
 
     def __init__(self,
-                 active_backend_id: str = None,
+                 active_backend_id: Optional[str] = None,
                  *args,
                  **kwargs) -> None:
         super(RBDDriver, self).__init__(*args, **kwargs)
@@ -1531,9 +1533,9 @@ def _demote_volumes(self,
             result.append(demoted)
         return result
 
-    def _get_failover_target_config(self,
-                                    secondary_id: str = None) -> Tuple[str,
-                                                                       dict]:
+    def _get_failover_target_config(
+            self,
+            secondary_id: Optional[str] = None) -> Tuple[str, dict]:
         if not secondary_id:
             # In auto mode exclude failback and active
             candidates = set(self._target_names).difference(
@@ -1587,7 +1589,7 @@ def failover_completed(self,
     def failover_host(self,
                       context: context.RequestContext,
                       volumes: List[Volume],
-                      secondary_id: str = None,
+                      secondary_id: Optional[str] = None,
                       groups: Optional[List] = None) -> Tuple[str,
                                                               List[Volume],
                                                               List]:

cinder/volume/flows/api/create_volume.py

@@ -257,7 +257,8 @@ def _extract_availability_zones(
             snapshot,
             source_volume,
             group: Optional[dict],
-            volume_type: Dict[str, Any] = None) -> Tuple[List[str], bool]:
+            volume_type: Optional[Dict[str, Any]] = None) -> Tuple[List[str],
+                                                                   bool]:
         """Extracts and returns a validated availability zone list.
 
         This function will extract the availability zone (if not provided) from

cinder/volume/rpcapi.py

@@ -146,8 +146,8 @@ class VolumeAPI(rpc.RPCAPI):
     BINARY = constants.VOLUME_BINARY
 
     def _get_cctxt(self,
-                   host: str = None,
-                   version: Union[str, Tuple[str, ...]] = None,
+                   host: Optional[str] = None,
+                   version: Optional[Union[str, Tuple[str, ...]]] = None,
                    **kwargs) -> rpc.RPCAPI:
         if host:
             server = volume_utils.extract_host(host)