python: type generated client using Self (#16693)

* python: type generated client using Self

This doesn't offer a clear win but this helps for:

* Using modern types and making the typing intent clearer
* Decreasing the need for `from __future__ import annotations`, since a
  class can now refer to itself without using its name
* Using more `cls` to automatically refer to the class, instead of
  respecifying the class name every time

Self is available from Python 3.11 and is provided in typing_extensions
(since 4.0.0) as a fallback for older versions

See: https://peps.python.org/pep-0673/
See: https://github.com/python/typing_extensions/blob/main/CHANGELOG.md#added-in-version-400

* generate code

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

@@ -15,6 +15,10 @@ import re  # noqa: F401
 from typing import Union, Any, List, TYPE_CHECKING, Optional, Dict
 from typing_extensions import Literal
 from pydantic import StrictStr, Field
+try:
+    from typing import Self
+except ImportError:
+    from typing_extensions import Self
 
 {{#lambda.uppercase}}{{{classname}}}{{/lambda.uppercase}}_ANY_OF_SCHEMAS = [{{#anyOf}}"{{.}}"{{^-last}}, {{/-last}}{{/anyOf}}]
 
@@ -97,13 +101,13 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
             return v
 
     @classmethod
-    def from_dict(cls, obj: dict) -> {{{classname}}}:
+    def from_dict(cls, obj: dict) -> Self:
         return cls.from_json(json.dumps(obj))
 
     @classmethod
-    def from_json(cls, json_str: str) -> {{{classname}}}:
+    def from_json(cls, json_str: str) -> Self:
         """Returns the object represented by the json string"""
-        instance = {{{classname}}}.model_construct()
+        instance = cls.model_construct()
         {{#isNullable}}
         if json_str is None:
             return instance

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

@@ -6,6 +6,10 @@ from enum import Enum
 {{#vendorExtensions.x-py-datetime-imports}}{{#-first}}from datetime import{{/-first}} {{{.}}}{{^-last}},{{/-last}}{{/vendorExtensions.x-py-datetime-imports}}
 {{#vendorExtensions.x-py-typing-imports}}{{#-first}}from typing import{{/-first}} {{{.}}}{{^-last}},{{/-last}}{{/vendorExtensions.x-py-typing-imports}}
 {{#vendorExtensions.x-py-pydantic-imports}}{{#-first}}from pydantic import{{/-first}} {{{.}}}{{^-last}},{{/-last}}{{/vendorExtensions.x-py-pydantic-imports}}
+try:
+    from typing import Self
+except ImportError:
+    from typing_extensions import Self
 
 
 class {{classname}}({{vendorExtensions.x-py-enum-type}}, Enum):
@@ -22,9 +26,9 @@ class {{classname}}({{vendorExtensions.x-py-enum-type}}, Enum):
     {{/enumVars}}
 
     @classmethod
-    def from_json(cls, json_str: str) -> {{{classname}}}:
+    def from_json(cls, json_str: str) -> Self:
         """Create an instance of {{classname}} from a JSON string"""
-        return {{classname}}(json.loads(json_str))
+        return cls(json.loads(json_str))
 
     {{#defaultValue}}
 

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

@@ -12,6 +12,11 @@ import json
 {{#vendorExtensions.x-py-model-imports}}
 {{{.}}}
 {{/vendorExtensions.x-py-model-imports}}
+from typing import Dict, Any
+try:
+    from typing import Self
+except ImportError:
+    from typing_extensions import Self
 
 class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}):
     """
@@ -113,7 +118,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
         return json.dumps(self.to_dict())
 
     @classmethod
-    def from_json(cls, json_str: str) -> {{^hasChildren}}{{{classname}}}{{/hasChildren}}{{#hasChildren}}{{#discriminator}}Union({{#children}}{{{classname}}}{{^-last}}, {{/-last}}{{/children}}){{/discriminator}}{{^discriminator}}{{{classname}}}{{/discriminator}}{{/hasChildren}}:
+    def from_json(cls, json_str: str) -> {{^hasChildren}}Self{{/hasChildren}}{{#hasChildren}}{{#discriminator}}Union[{{#children}}Self{{^-last}}, {{/-last}}{{/children}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}{{/hasChildren}}:
         """Create an instance of {{{classname}}} from a JSON string"""
         return cls.from_dict(json.loads(json_str))
 
@@ -215,7 +220,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
         return _dict
 
     @classmethod
-    def from_dict(cls, obj: dict) -> {{^hasChildren}}{{{classname}}}{{/hasChildren}}{{#hasChildren}}{{#discriminator}}Union({{#children}}{{{classname}}}{{^-last}}, {{/-last}}{{/children}}){{/discriminator}}{{^discriminator}}{{{classname}}}{{/discriminator}}{{/hasChildren}}:
+    def from_dict(cls, obj: dict) -> {{^hasChildren}}Self{{/hasChildren}}{{#hasChildren}}{{#discriminator}}Union[{{#children}}Self{{^-last}}, {{/-last}}{{/children}}]{{/discriminator}}{{^discriminator}}Self{{/discriminator}}{{/hasChildren}}:
         """Create an instance of {{{classname}}} from a dict"""
         {{#hasChildren}}
         {{#discriminator}}
@@ -235,7 +240,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
             return None
 
         if not isinstance(obj, dict):
-            return {{{classname}}}.model_validate(obj)
+            return cls.model_validate(obj)
 
         {{#disallowAdditionalPropertiesIfNotPresent}}
         {{^isAdditionalPropertiesTrue}}
@@ -246,7 +251,7 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
 
         {{/isAdditionalPropertiesTrue}}
         {{/disallowAdditionalPropertiesIfNotPresent}}
-        _obj = {{{classname}}}.model_validate({
+        _obj = cls.model_validate({
             {{#allVars}}
             {{#isContainer}}
             {{#isArray}}

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

@@ -15,6 +15,10 @@ import re  # noqa: F401
 from typing import Union, Any, List, TYPE_CHECKING, Optional, Dict
 from typing_extensions import Literal
 from pydantic import StrictStr, Field
+try:
+    from typing import Self
+except ImportError:
+    from typing_extensions import Self
 
 {{#lambda.uppercase}}{{{classname}}}{{/lambda.uppercase}}_ONE_OF_SCHEMAS = [{{#oneOf}}"{{.}}"{{^-last}}, {{/-last}}{{/oneOf}}]
 
@@ -97,13 +101,13 @@ class {{classname}}({{#parent}}{{{.}}}{{/parent}}{{^parent}}BaseModel{{/parent}}
             return v
 
     @classmethod
-    def from_dict(cls, obj: dict) -> {{{classname}}}:
+    def from_dict(cls, obj: dict) -> Self:
         return cls.from_json(json.dumps(obj))
 
     @classmethod
-    def from_json(cls, json_str: str) -> {{{classname}}}:
+    def from_json(cls, json_str: str) -> Self:
         """Returns the object represented by the json string"""
-        instance = {{{classname}}}.model_construct()
+        instance = cls.model_construct()
         {{#isNullable}}
         if json_str is None:
             return instance

samples/client/echo_api/python-disallowAdditionalPropertiesIfNotPresent-true/openapi_client/api/auth_api.py

@@ -18,6 +18,7 @@
 import warnings
 
 from pydantic import validate_call, ValidationError
+from typing import Dict, List, Optional, Tuple
 
 
 from openapi_client.api_client import ApiClient
@@ -130,28 +131,28 @@ def test_auth_http_basic_with_http_info(self, **kwargs) -> ApiResponse:  # noqa:
             _params[_key] = _val
         del _params['kwargs']
 
-        _collection_formats = {}
+        _collection_formats: Dict[str, str] = {}
 
         # process the path parameters
-        _path_params = {}
+        _path_params: Dict[str, str] = {}
 
         # process the query parameters
-        _query_params = []
+        _query_params: List[Tuple[str, str]] = []
         # process the header parameters
         _header_params = dict(_params.get('_headers', {}))
         # process the form parameters
-        _form_params = []
-        _files = {}
+        _form_params: List[Tuple[str, str]] = []
+        _files: Dict[str, str] = {}
         # process the body parameter
         _body_params = None
         # set the HTTP header `Accept`
         _header_params['Accept'] = self.api_client.select_header_accept(
             ['text/plain'])  # noqa: E501
 
         # authentication setting
-        _auth_settings = ['http_auth']  # noqa: E501
+        _auth_settings: List[str] = ['http_auth']  # noqa: E501
 
-        _response_types_map = {
+        _response_types_map: Dict[str, Optional[str]] = {
             '200': "str",
         }