Disable implicit introduction of Optional via default parameter.

Citing PEP 484 (Type Hints):

    A past version of this PEP allowed type checkers to assume an optional
    type when the default value is None, as in this code:

        def handle_employee(e: Employee = None): ...

    This would have been treated as equivalent to:

        def handle_employee(e: Optional[Employee] = None) -> None: ...

    This is no longer the recommended behavior.  Type checkers should move
    towards requiring the optional type to be made explicit.

Currently mypy has the old behavior as the default, but this will probably
changed soon, see python/mypy#9091.

Change-Id: I7349f50345ba98337b821a5a2006c60dfe342341

cmk/base/api/agent_based/utils.py

@@ -150,9 +150,9 @@ def check_levels(
     *,
     levels_upper=None,  # tpye: Optional[Tuple[float, float]]
     levels_lower=None,  # tpye: Optional[Tuple[float, float]]
-    metric_name: str = None,
-    render_func: Callable[[float], str] = None,
-    label: str = None,
+    metric_name: Optional[str] = None,
+    render_func: Optional[Callable[[float], str]] = None,
+    label: Optional[str] = None,
     boundaries: Optional[Tuple[Optional[float], Optional[float]]] = None,
 ) -> Generator[Union[Result, Metric], None, None]:
     """Generic function for checking a value against levels.

cmk/base/check_api_utils.py

@@ -36,8 +36,8 @@ class Service:
     def __init__(self,
                  item: Item,
                  parameters: LegacyCheckParameters = None,
-                 service_labels: DiscoveredServiceLabels = None,
-                 host_labels: DiscoveredHostLabels = None) -> None:
+                 service_labels: Optional[DiscoveredServiceLabels] = None,
+                 host_labels: Optional[DiscoveredHostLabels] = None) -> None:
         self.item = item
         self.parameters = parameters
         self.service_labels = service_labels or DiscoveredServiceLabels()

cmk/base/check_utils.py

@@ -63,7 +63,7 @@ def __init__(
         item: Item,
         description: str,
         parameters: LegacyCheckParameters,
-        service_labels: DiscoveredServiceLabels = None,
+        service_labels: Optional[DiscoveredServiceLabels] = None,
     ) -> None:
         self._check_plugin_name = check_plugin_name
         self._item = item

cmk/base/crash_reporting.py

@@ -35,9 +35,10 @@ def type(cls) -> str:
         return "base"
 
     @classmethod
-    def from_exception(cls,
-                       details: Dict = None,
-                       type_specific_attributes: Dict = None) -> crash_reporting.ABCCrashReport:
+    def from_exception(
+            cls,
+            details: Optional[Dict] = None,
+            type_specific_attributes: Optional[Dict] = None) -> crash_reporting.ABCCrashReport:
         return super(CMKBaseCrashReport, cls).from_exception(details={
             "argv": sys.argv,
             "env": dict(os.environ),

cmk/base/modes/__init__.py

@@ -201,13 +201,13 @@ class Option:
     def __init__(self,
                  long_option: str,
                  short_help: str,
-                 short_option: str = None,
+                 short_option: Optional[str] = None,
                  argument: bool = False,
-                 argument_descr: str = None,
-                 argument_conv: ConvertFunction = None,
+                 argument_descr: Optional[str] = None,
+                 argument_conv: Optional[ConvertFunction] = None,
                  argument_optional: bool = False,
                  count: bool = False,
-                 handler_function: OptionFunction = None) -> None:
+                 handler_function: Optional[OptionFunction] = None) -> None:
         # TODO: This disable is needed because of a pylint bug. Remove one day.
         super(Option, self).__init__()  # pylint: disable=bad-super-call
         self.long_option = long_option
@@ -290,14 +290,12 @@ def __init__(self,
                  short_option: Optional[OptionName] = None,
                  argument: bool = False,
                  argument_descr: Optional[str] = None,
-                 argument_conv: ConvertFunction = None,
+                 argument_conv: Optional[ConvertFunction] = None,
                  argument_optional: bool = False,
                  long_help: Optional[List[str]] = None,
                  needs_config: bool = True,
                  needs_checks: bool = True,
                  sub_options: Optional[List[Option]] = None) -> None:
-        # TODO: This disable is needed because of a pylint bug. Remove one day.
-        # pylint: disable=bad-super-call
         super(Mode, self).__init__(long_option,
                                    short_help,
                                    short_option,

cmk/ec/actions.py

@@ -8,7 +8,7 @@
 import os
 import subprocess
 import time
-from typing import Any, Dict, Set
+from typing import Any, Dict, Optional, Set
 
 import cmk.utils.debug
 import cmk.utils.defines
@@ -262,7 +262,7 @@ def to_string(v: Any) -> str:
 def do_notify(event_server: Any,
               logger: Logger,
               event: Any,
-              username: bool = None,
+              username: Optional[bool] = None,
               is_cancelling: bool = False) -> None:
     if _core_has_notifications_disabled(event, logger):
         return

cmk/gui/background_job.py

@@ -271,7 +271,7 @@ class BackgroundJob:
     # TODO: Make this an abstract property
     job_prefix = "unnamed-job"
 
-    def __init__(self, job_id: str, logger: logging.Logger = None, **kwargs: Any) -> None:
+    def __init__(self, job_id: str, logger: Optional[logging.Logger] = None, **kwargs: Any) -> None:
         super(BackgroundJob, self).__init__()
         self._job_id = job_id
         self._job_base_dir = BackgroundJobDefines.base_dir

cmk/gui/breadcrumb.py

@@ -21,7 +21,7 @@
 
 
 class Breadcrumb(MutableSequence[BreadcrumbItem]):
-    def __init__(self, items: Iterable[BreadcrumbItem] = None):
+    def __init__(self, items: Optional[Iterable[BreadcrumbItem]] = None):
         super().__init__()
         self._items: List[BreadcrumbItem] = list(items) if items else []
 

cmk/gui/forms.py

@@ -42,7 +42,7 @@ def edit_dictionaries(dictionaries: 'List[Tuple[str, Union[Transform, Dictionary
                       validate: Optional[Callable[[Any], None]] = None,
                       buttontext: Optional[str] = None,
                       title: Optional[str] = None,
-                      buttons: List[Tuple[str, str, str]] = None,
+                      buttons: Optional[List[Tuple[str, str, str]]] = None,
                       method: str = "GET",
                       preview: bool = False,
                       varprefix: str = "",

cmk/gui/htmllib.py

@@ -1812,7 +1812,7 @@ def body_end(self) -> None:
 
     def begin_form(self,
                    name: str,
-                   action: str = None,
+                   action: Optional[str] = None,
                    method: str = "GET",
                    onsubmit: Optional[str] = None,
                    add_transid: bool = True) -> None:
@@ -1857,7 +1857,9 @@ def add_form_var(self, varname: str) -> None:
     # field to the form - *if* they are not used in any input
     # field. (this is the reason why you must not add any further
     # input fields after this method has been called).
-    def hidden_fields(self, varlist: List[str] = None, add_action_vars: bool = False) -> None:
+    def hidden_fields(self,
+                      varlist: Optional[List[str]] = None,
+                      add_action_vars: bool = False) -> None:
         if varlist is not None:
             for var in varlist:
                 self.hidden_field(var, self.request.var(var, ""))
@@ -1870,7 +1872,7 @@ def hidden_fields(self, varlist: List[str] = None, add_action_vars: bool = False
     def hidden_field(self,
                      var: str,
                      value: HTMLTagValue,
-                     id_: str = None,
+                     id_: Optional[str] = None,
                      add_var: bool = False,
                      class_: CSSSpec = None) -> None:
         self.write_html(
@@ -1879,7 +1881,7 @@ def hidden_field(self,
     def render_hidden_field(self,
                             var: str,
                             value: HTMLTagValue,
-                            id_: str = None,
+                            id_: Optional[str] = None,
                             add_var: bool = False,
                             class_: CSSSpec = None) -> HTML:
         if value is None:
@@ -2102,7 +2104,7 @@ def text_input(self,
                    cssclass: str = "text",
                    size: Union[None, str, int] = None,
                    label: Optional[str] = None,
-                   id_: str = None,
+                   id_: Optional[str] = None,
                    submit: Optional[str] = None,
                    try_max_width: bool = False,
                    read_only: bool = False,
@@ -2224,7 +2226,7 @@ def password_input(self,
                        cssclass: str = "text",
                        size: Union[None, str, int] = None,
                        label: Optional[str] = None,
-                       id_: str = None,
+                       id_: Optional[str] = None,
                        submit: Optional[str] = None,
                        try_max_width: bool = False,
                        read_only: bool = False,

cmk/gui/plugins/dashboard/utils.py

@@ -581,7 +581,7 @@ def _transform_builtin_dashboards() -> None:
 def copy_view_into_dashlet(dashlet: DashletConfig,
                            nr: DashletId,
                            view_name: str,
-                           add_context: VisualContext = None,
+                           add_context: Optional[VisualContext] = None,
                            load_from_all_views: bool = False) -> None:
     permitted_views = get_permitted_views()
 

cmk/gui/plugins/openapi/restful_objects/constructors.py

@@ -679,7 +679,7 @@ def collection_item(
     )
 
 
-def serve_json(data: Serializable, profile: Dict[str, str] = None) -> Response:
+def serve_json(data: Serializable, profile: Optional[Dict[str, str]] = None) -> Response:
     content_type = 'application/json'
     if profile is not None:
         content_type += ';profile="%s"' % (profile,)

cmk/gui/plugins/openapi/restful_objects/decorators.py

@@ -68,14 +68,14 @@ def _reduce_to_primitives(
 def endpoint_schema(path: str,
                     name: EndpointName,
                     method: HTTPMethod = 'get',
-                    parameters: Sequence[AnyParameterAndReference] = None,
+                    parameters: Optional[Sequence[AnyParameterAndReference]] = None,
                     content_type: str = 'application/json',
                     output_empty: bool = False,
                     response_schema: ResponseSchema = None,
                     request_schema: RequestSchema = None,
                     request_body_required: bool = True,
                     error_schema: Schema = ApiError,
-                    etag: ETagBehaviour = None,
+                    etag: Optional[ETagBehaviour] = None,
                     will_do_redirects: bool = False,
                     **options: dict):
     """Mark the function as a REST-API endpoint.

cmk/gui/plugins/openapi/restful_objects/type_defs.py

@@ -3,8 +3,7 @@
 # Copyright (C) 2020 tribe29 GmbH - License: GNU General Public License v2
 # This file is part of Checkmk (https://checkmk.com). It is subject to the terms and
 # conditions defined in the file COPYING, which is part of this source code package.
-from typing import Callable, Dict, Any, Optional, Sequence, Tuple, Type, Union, List, Literal, \
-    TypedDict
+from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Tuple, Type, TypedDict, Union
 
 from marshmallow import Schema  # type: ignore[import]
 
@@ -133,15 +132,15 @@
 
 
 def _translate_to_openapi_keys(
-    name: str = None,
-    location: LocationType = None,
+    name: Optional[str] = None,
+    location: Optional[LocationType] = None,
     description: Optional[str] = None,
-    required: bool = None,
-    example: str = None,
-    allow_emtpy: bool = None,
-    schema_type: OpenAPISchemaType = None,
+    required: Optional[bool] = None,
+    example: Optional[str] = None,
+    allow_emtpy: Optional[bool] = None,
+    schema_type: Optional[OpenAPISchemaType] = None,
     schema_string_pattern: Optional[str] = None,
-    schema_string_format: str = None,
+    schema_string_format: Optional[str] = None,
     schema_num_minimum: Optional[int] = None,
     schema_num_maximum: Optional[int] = None,
 ):
@@ -201,15 +200,15 @@ def __init__(self, *seq, **kwargs):
 
     def __call__(
         self,
-        name: str = None,
-        description: str = None,
-        location: LocationType = None,
-        required: bool = None,
-        allow_empty: bool = None,
-        example: str = None,
-        schema_type: OpenAPISchemaType = None,
-        schema_string_pattern: str = None,
-        schema_string_format: str = None,
+        name: Optional[str] = None,
+        description: Optional[str] = None,
+        location: Optional[LocationType] = None,
+        required: Optional[bool] = None,
+        allow_empty: Optional[bool] = None,
+        example: Optional[str] = None,
+        schema_type: Optional[OpenAPISchemaType] = None,
+        schema_string_pattern: Optional[str] = None,
+        schema_string_format: Optional[str] = None,
         schema_num_minimum: Optional[int] = None,
         schema_num_maximum: Optional[int] = None,
     ):
@@ -265,10 +264,10 @@ def create(
         description: Optional[str] = None,
         required: bool = True,
         allow_emtpy: bool = False,
-        example: str = None,
-        schema_type: OpenAPISchemaType = 'string',
+        example: Optional[str] = None,
+        schema_type: Optional[OpenAPISchemaType] = 'string',
         schema_string_pattern: Optional[str] = None,
-        schema_string_format: str = None,
+        schema_string_format: Optional[str] = None,
         schema_num_minimum: Optional[int] = None,
         schema_num_maximum: Optional[int] = None,
     ) -> 'ParamDict':

cmk/gui/plugins/userdb/utils.py

@@ -207,7 +207,8 @@ def load_connection_config(lock: bool = False) -> List[UserConnectionSpec]:
     return store.load_from_mk_file(filename, "user_connections", default=[], lock=lock)
 
 
-def save_connection_config(connections: List[UserConnectionSpec], base_dir: str = None) -> None:
+def save_connection_config(connections: List[UserConnectionSpec],
+                           base_dir: Optional[str] = None) -> None:
     if not base_dir:
         base_dir = _multisite_dir()
     store.mkdir(base_dir)

cmk/gui/plugins/views/utils.py

@@ -1146,7 +1146,7 @@ def get_graph_timerange_from_painter_options() -> TimeRange:
 def paint_age(timestamp: Timestamp,
               has_been_checked: bool,
               bold_if_younger_than: int,
-              mode: str = None,
+              mode: Optional[str] = None,
               what: str = 'past') -> CellSpec:
     if not has_been_checked:
         return "age", "-"

cmk/gui/userdb.py

@@ -468,7 +468,7 @@ def declare_user_attribute(name: str,
                            user_editable: bool = True,
                            permission: Optional[str] = None,
                            show_in_table: bool = False,
-                           topic: str = None,
+                           topic: Optional[str] = None,
                            add_custom_macro: bool = False,
                            domain: str = "multisite",
                            from_config: bool = False) -> None:
@@ -794,7 +794,8 @@ def _cleanup_old_user_profiles(updated_profiles: Users) -> None:
                     os.unlink(entry + '/' + to_delete)
 
 
-def write_contacts_and_users_file(profiles: Users, custom_default_config_dir: str = None) -> None:
+def write_contacts_and_users_file(profiles: Users,
+                                  custom_default_config_dir: Optional[str] = None) -> None:
     non_contact_keys = _non_contact_keys()
     multisite_keys = _multisite_keys()
     updated_profiles = _add_custom_macro_attributes(profiles)