python: enable more mypy checks 1/n

modules/openapi-generator/src/main/resources/python/api.mustache

@@ -10,7 +10,7 @@ from typing_extensions import Annotated
 {{import}}
 {{/imports}}
 
-from {{packageName}}.api_client import ApiClient
+from {{packageName}}.api_client import ApiClient, RequestSerialized
 from {{packageName}}.api_response import ApiResponse
 from {{packageName}}.rest import RESTResponseType
 
@@ -77,7 +77,7 @@ class {{classname}}:
         _content_type,
         _headers,
         _host_index,
-    ) -> Tuple:
+    ) -> RequestSerialized:
 
         {{#servers.0}}
         _hosts = [{{#servers}}

modules/openapi-generator/src/main/resources/python/api_client.mustache

@@ -11,13 +11,13 @@ import re
 import tempfile
 
 from urllib.parse import quote
-from typing import Tuple, Optional, List
+from typing import Tuple, Optional, List, Dict
 {{#tornado}}
 import tornado.gen
 {{/tornado}}
 
 from {{packageName}}.configuration import Configuration
-from {{packageName}}.api_response import ApiResponse
+from {{packageName}}.api_response import ApiResponse, T as ApiResponseT
 import {{modelPackage}}
 from {{packageName}} import rest
 from {{packageName}}.exceptions import (
@@ -30,6 +30,7 @@ from {{packageName}}.exceptions import (
     ServiceException
 )
 
+RequestSerialized = Tuple[str, str, Dict[str, str], Optional[str], List[str]]
 
 class ApiClient:
     """Generic API client for OpenAPI client library builds.
@@ -151,7 +152,7 @@ class ApiClient:
         collection_formats=None,
         _host=None,
         _request_auth=None
-    ) -> Tuple:
+    ) -> RequestSerialized:
 
         """Builds the HTTP request params needed by the request.
         :param method: Method to call.
@@ -287,8 +288,8 @@ class ApiClient:
     def response_deserialize(
         self,
         response_data: rest.RESTResponse,
-        response_types_map=None
-    ) -> ApiResponse:
+        response_types_map: Optional[Dict[str, ApiResponseT]]=None
+    ) -> ApiResponse[ApiResponseT]:
         """Deserializes response into an object.
         :param response_data: RESTResponse object to be deserialized.
         :param response_types_map: dict of response types.
@@ -409,12 +410,16 @@ class ApiClient:
 
         if isinstance(klass, str):
             if klass.startswith('List['):
-                sub_kls = re.match(r'List\[(.*)]', klass).group(1)
+                m = re.match(r'List\[(.*)]', klass)
+                assert m is not None, "Malformed List type definition"
+                sub_kls = m.group(1)
                 return [self.__deserialize(sub_data, sub_kls)
                         for sub_data in data]
 
             if klass.startswith('Dict['):
-                sub_kls = re.match(r'Dict\[([^,]*), (.*)]', klass).group(2)
+                m = re.match(r'Dict\[([^,]*), (.*)]', klass)
+                assert m is not None, "Malformed Dict type definition"
+                sub_kls = m.group(2)
                 return {k: self.__deserialize(v, sub_kls)
                         for k, v in data.items()}
 
@@ -442,7 +447,7 @@ class ApiClient:
         :param dict collection_formats: Parameter collection formats
         :return: Parameters as list of tuples, collections formatted
         """
-        new_params = []
+        new_params: List[Tuple[str, str]] = []
         if collection_formats is None:
             collection_formats = {}
         for k, v in params.items() if isinstance(params, dict) else params:
@@ -472,7 +477,7 @@ class ApiClient:
         :param dict collection_formats: Parameter collection formats
         :return: URL query string (e.g. a=Hello%20World&b=123)
         """
-        new_params = []
+        new_params: List[Tuple[str, str]] = []
         if collection_formats is None:
             collection_formats = {}
         for k, v in params.items() if isinstance(params, dict) else params:
@@ -666,10 +671,12 @@ class ApiClient:
 
         content_disposition = response.getheader("Content-Disposition")
         if content_disposition:
-            filename = re.search(
+            m = re.search(
                 r'filename=[\'"]?([^\'"\s]+)[\'"]?',
                 content_disposition
-            ).group(1)
+            )
+            assert m is not None, "Unexpected 'content-disposition' header value"
+            filename = m.group(1)
             path = os.path.join(os.path.dirname(path), filename)
 
         with open(path, "wb") as f:

modules/openapi-generator/src/main/resources/python/asyncio/rest.mustache

@@ -6,7 +6,7 @@ import io
 import json
 import re
 import ssl
-from typing import Optional
+from typing import Optional, Union
 
 import aiohttp
 import aiohttp_retry
@@ -189,6 +189,7 @@ class RESTClientObject:
                          declared content type."""
                 raise ApiException(status=0, reason=msg)
 
+        pool_manager: Union[aiohttp.ClientSession, aiohttp_retry.RetryClient]
         if self.retry_client is not None and method in ALLOW_RETRY_METHODS:
             pool_manager = self.retry_client
         else:

modules/openapi-generator/src/main/resources/python/configuration.mustache

@@ -4,10 +4,12 @@
 
 import copy
 import logging
+from logging import FileHandler
 {{^asyncio}}
 import multiprocessing
 {{/asyncio}}
 import sys
+from typing import Optional
 import urllib3
 
 import http.client as httplib
@@ -204,7 +206,7 @@ conf = {{{packageName}}}.Configuration(
         self.logger_stream_handler = None
         """Log stream handler
         """
-        self.logger_file_handler = None
+        self.logger_file_handler: Optional[FileHandler] = None
         """Log file handler
         """
         self.logger_file = None
@@ -252,7 +254,7 @@ conf = {{{packageName}}}.Configuration(
         """
         {{/asyncio}}
 
-        self.proxy = None
+        self.proxy: Optional[str] = None
         """Proxy URL
         """
         self.proxy_headers = None

modules/openapi-generator/src/main/resources/python/model_anyof.mustache

@@ -95,7 +95,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
             return v
 
     @classmethod
-    def from_dict(cls, obj: dict) -> Self:
+    def from_dict(cls, obj: Dict[str, Any]) -> Self:
         return cls.from_json(json.dumps(obj))
 
     @classmethod
@@ -159,7 +159,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
         else:
             return json.dumps(self.actual_instance)
 
-    def to_dict(self) -> Optional[Union[Dict, {{#anyOf}}{{.}}{{^-last}}, {{/-last}}{{/anyOf}}]]:
+    def to_dict(self) -> Optional[Union[Dict[str, Any], {{#anyOf}}{{.}}{{^-last}}, {{/-last}}{{/anyOf}}]]:
         """Returns the dict representation of the actual instance"""
         if self.actual_instance is None:
             return None

modules/openapi-generator/src/main/resources/python/model_generic.mustache

@@ -93,7 +93,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
     }
 
     @classmethod
-    def get_discriminator_value(cls, obj: Dict) -> Optional[str]:
+    def get_discriminator_value(cls, obj: Dict[str, Any]) -> Optional[str]:
         """Returns the discriminator value (object type) of the data"""
         discriminator_value = obj[cls.__discriminator_property_name]
         if discriminator_value:
@@ -236,7 +236,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
 
     {{#hasChildren}}
     @classmethod
-    def from_dict(cls, obj: Dict) -> Optional[{{#discriminator}}Union[{{#children}}Self{{^-last}}, {{/-last}}{{/children}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}]:
+    def from_dict(cls, obj: Dict[str, Any]) -> Optional[{{#discriminator}}Union[{{#children}}Self{{^-last}}, {{/-last}}{{/children}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}]:
         """Create an instance of {{{classname}}} from a dict"""
         {{#discriminator}}
         # look up the object type based on discriminator mapping
@@ -252,7 +252,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
     {{/hasChildren}}
     {{^hasChildren}}
     @classmethod
-    def from_dict(cls, obj: Optional[Dict]) -> Optional[Self]:
+    def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
         """Create an instance of {{{classname}}} from a dict"""
         if obj is None:
             return None

modules/openapi-generator/src/main/resources/python/model_oneof.mustache

@@ -93,11 +93,16 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
             return v
 
     @classmethod
-    def from_dict(cls, obj: dict) -> Self:
+    def from_dict(cls, obj: Union[str, Dict[str, Any]]) -> Self:
         return cls.from_json(json.dumps(obj))
 
     @classmethod
+    {{#isNullable}}
+    def from_json(cls, json_str: Optional[str]) -> Self:
+    {{/isNullable}}
+    {{^isNullable}}
     def from_json(cls, json_str: str) -> Self:
+    {{/isNullable}}
         """Returns the object represented by the json string"""
         instance = cls.model_construct()
         {{#isNullable}}
@@ -180,7 +185,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
         else:
             return json.dumps(self.actual_instance)
 
-    def to_dict(self) -> Optional[Union[Dict, {{#oneOf}}{{{.}}}{{^-last}}, {{/-last}}{{/oneOf}}]]:
+    def to_dict(self) -> Optional[Union[Dict[str, Any], {{#oneOf}}{{{.}}}{{^-last}}, {{/-last}}{{/oneOf}}]]:
         """Returns the dict representation of the actual instance"""
         if self.actual_instance is None:
             return None

modules/openapi-generator/src/main/resources/python/pyproject.mustache

@@ -49,3 +49,34 @@ files = [
   #"test",  # auto-generated tests
   "tests", # hand-written tests
 ]
+# TODO: enable "strict" once all these individual checks are passing
+# strict = true
+
+# List from: https://mypy.readthedocs.io/en/stable/existing_code.html#introduce-stricter-options
+warn_unused_configs = true
+warn_redundant_casts = true
+warn_unused_ignores = true
+
+## Getting these passing should be easy
+strict_equality = true
+strict_concatenate = true
+
+## Strongly recommend enabling this one as soon as you can
+check_untyped_defs = true
+
+## These shouldn't be too much additional work, but may be tricky to
+## get passing if you use a lot of untyped libraries
+disallow_subclassing_any = true
+disallow_untyped_decorators = true
+disallow_any_generics = true
+
+### These next few are various gradations of forcing use of type annotations
+#disallow_untyped_calls = true
+#disallow_incomplete_defs = true
+#disallow_untyped_defs = true
+#
+### This one isn't too hard to get passing, but return on investment is lower
+#no_implicit_reexport = true
+#
+### This one can be tricky to get passing if you use a lot of untyped libraries
+#warn_return_any = true

modules/openapi-generator/src/main/resources/python/rest.mustache

@@ -202,14 +202,13 @@ class RESTClientObject:
                         preload_content=False
                     )
                 # Pass a `string` parameter directly in the body to support
-                # other content types than Json when `body` argument is
-                # provided in serialized form
+                # other content types than JSON when `body` argument is
+                # provided in serialized form.
                 elif isinstance(body, str) or isinstance(body, bytes):
-                    request_body = body
                     r = self.pool_manager.request(
                         method,
                         url,
-                        body=request_body,
+                        body=body,
                         timeout=timeout,
                         headers=headers,
                         preload_content=False