#21582 [BUG][dart-dio] Bug generating inline enums with common names (#21591)

* #21582 [BUG][dart-dio] Bug generating inline enums with common names

* #21582 [BUG][dart-dio] Bug generating inline enums with common names added petstore test

* #21582 [BUG][dart-dio] Bug generating inline enums with common names added generated samples to commit.

* #21582 [BUG][dart-dio] Bug generating inline enums with common names removed bug test files that were duplicates

* #21582 [BUG][dart-dio] Bug generating inline enums with common names. Added generated files that were missed.

* #21582 [BUG][dart-dio] Bug generating inline enums with common names. Added generated files that were missed.

* #21582 [BUG][dart-dio] Bug generating inline enums with common names. Added generated files that where updated as a result of changes in master.

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractDartCodegen.java

@@ -576,6 +576,12 @@ public abstract class AbstractDartCodegen extends DefaultCodegen {
                 // inner items e.g. enums in collections, only works for one level
                 // but same is the case for DefaultCodegen
                 property.setDatatypeWithEnum(property.datatypeWithEnum.replace(property.items.datatypeWithEnum, enumName));
+                // Because properties are cached in org.openapitools.codegen.DefaultCodegen.fromProperty(java.lang.String, io.swagger.v3.oas.models.media.Schema, boolean, boolean)
+                // then the same object could be for multiple properties where the name of the inline enum is the same
+                // in 2 different classes and the following renaming will impact properties in other classes we
+                // therefore clone them before editing
+                property.items = property.items.clone();
+                property.mostInnerItems = property.items;
                 property.items.setDatatypeWithEnum(enumName);
                 property.items.setEnumName(enumName);
             } else {

modules/openapi-generator/src/test/resources/3_0/dart/petstore-with-fake-endpoints-models-for-testing.yaml

@@ -1303,6 +1303,19 @@ paths:
       responses:
         200:
           description: The instance started successfully
+  /fake/duplicate-inline-enums:
+    get:
+      tags:
+        - fake
+      summary: test objects with duplicate inline enums see issue# 21582
+      operationId: fake-duplicate-inline-enum
+      responses:
+        '200':
+          description: OK
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ObjectThatReferencesObjectsWithDuplicateInlineEnums'
 servers:
   - url: 'http://{server}.swagger.io:{port}/v2'
     description: petstore server
@@ -2081,3 +2094,36 @@ components:
           $ref: '#/components/schemas/TestEnum'
           default: ""
       title: TestItem
+    ObjectWithInlineEnum:
+      type: object
+      properties:
+        attribute:
+          description: 'Object one attribute enum'
+          type: 'array'
+          uniqueItems: true
+          items:
+            type: 'string'
+            enum: [
+              'value_one',
+              'value_two'
+            ]
+    ObjectWithDuplicateInlineEnum:
+      type: object
+      properties:
+        attribute:
+          description: 'Object two attribute enum'
+          type: 'array'
+          uniqueItems: true
+          items:
+            type: 'string'
+            enum: [
+              'value_one',
+              'value_two'
+            ]
+    ObjectThatReferencesObjectsWithDuplicateInlineEnums:
+      type: object
+      properties:
+        object_one:
+          $ref: '#/components/schemas/ObjectWithInlineEnum'
+        object_two:
+          $ref: '#/components/schemas/ObjectWithDuplicateInlineEnum'

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/.openapi-generator/FILES

@@ -40,7 +40,10 @@ doc/ModelReturn.md
 doc/Name.md
 doc/NullableClass.md
 doc/NumberOnly.md
+doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md
 doc/ObjectWithDeprecatedFields.md
+doc/ObjectWithDuplicateInlineEnum.md
+doc/ObjectWithInlineEnum.md
 doc/Order.md
 doc/OuterComposite.md
 doc/OuterEnum.md
@@ -110,7 +113,10 @@ lib/src/model/model_return.dart
 lib/src/model/name.dart
 lib/src/model/nullable_class.dart
 lib/src/model/number_only.dart
+lib/src/model/object_that_references_objects_with_duplicate_inline_enums.dart
 lib/src/model/object_with_deprecated_fields.dart
+lib/src/model/object_with_duplicate_inline_enum.dart
+lib/src/model/object_with_inline_enum.dart
 lib/src/model/order.dart
 lib/src/model/outer_composite.dart
 lib/src/model/outer_enum.dart

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/README.md

@@ -69,6 +69,7 @@ Class | Method | HTTP request | Description
 [*AnotherFakeApi*](doc/AnotherFakeApi.md) | [**call123testSpecialTags**](doc/AnotherFakeApi.md#call123testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
 [*DefaultApi*](doc/DefaultApi.md) | [**fooGet**](doc/DefaultApi.md#fooget) | **GET** /foo | 
 [*FakeApi*](doc/FakeApi.md) | [**fakeBigDecimalMap**](doc/FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+[*FakeApi*](doc/FakeApi.md) | [**fakeDuplicateInlineEnum**](doc/FakeApi.md#fakeduplicateinlineenum) | **GET** /fake/duplicate-inline-enums | test objects with duplicate inline enums see issue# 21582
 [*FakeApi*](doc/FakeApi.md) | [**fakeHealthGet**](doc/FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 [*FakeApi*](doc/FakeApi.md) | [**fakeHttpSignatureTest**](doc/FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 [*FakeApi*](doc/FakeApi.md) | [**fakeOuterBooleanSerialize**](doc/FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
@@ -150,7 +151,10 @@ Class | Method | HTTP request | Description
  - [Name](doc/Name.md)
  - [NullableClass](doc/NullableClass.md)
  - [NumberOnly](doc/NumberOnly.md)
+ - [ObjectThatReferencesObjectsWithDuplicateInlineEnums](doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md)
  - [ObjectWithDeprecatedFields](doc/ObjectWithDeprecatedFields.md)
+ - [ObjectWithDuplicateInlineEnum](doc/ObjectWithDuplicateInlineEnum.md)
+ - [ObjectWithInlineEnum](doc/ObjectWithInlineEnum.md)
  - [Order](doc/Order.md)
  - [OuterComposite](doc/OuterComposite.md)
  - [OuterEnum](doc/OuterEnum.md)

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/doc/FakeApi.md

@@ -10,6 +10,7 @@ All URIs are relative to *http://petstore.swagger.io:80/v2*
 Method | HTTP request | Description
 ------------- | ------------- | -------------
 [**fakeBigDecimalMap**](FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+[**fakeDuplicateInlineEnum**](FakeApi.md#fakeduplicateinlineenum) | **GET** /fake/duplicate-inline-enums | test objects with duplicate inline enums see issue# 21582
 [**fakeHealthGet**](FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 [**fakeHttpSignatureTest**](FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 [**fakeOuterBooleanSerialize**](FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
@@ -72,6 +73,43 @@ No authorization required
 
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
+# **fakeDuplicateInlineEnum**
+> ObjectThatReferencesObjectsWithDuplicateInlineEnums fakeDuplicateInlineEnum()
+
+test objects with duplicate inline enums see issue# 21582
+
+### Example
+```dart
+import 'package:openapi/api.dart';
+
+final api = Openapi().getFakeApi();
+
+try {
+    final response = api.fakeDuplicateInlineEnum();
+    print(response);
+} catch on DioException (e) {
+    print('Exception when calling FakeApi->fakeDuplicateInlineEnum: $e\n');
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+[**ObjectThatReferencesObjectsWithDuplicateInlineEnums**](ObjectThatReferencesObjectsWithDuplicateInlineEnums.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
 # **fakeHealthGet**
 > HealthCheckResult fakeHealthGet()
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md

@@ -0,0 +1,16 @@
+# openapi.model.ObjectThatReferencesObjectsWithDuplicateInlineEnums
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**objectOne** | [**ObjectWithInlineEnum**](ObjectWithInlineEnum.md) |  | [optional] 
+**objectTwo** | [**ObjectWithDuplicateInlineEnum**](ObjectWithDuplicateInlineEnum.md) |  | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/doc/ObjectWithDuplicateInlineEnum.md

@@ -0,0 +1,15 @@
+# openapi.model.ObjectWithDuplicateInlineEnum
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**attribute** | **Set<String>** | Object two attribute enum | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/doc/ObjectWithInlineEnum.md

@@ -0,0 +1,15 @@
+# openapi.model.ObjectWithInlineEnum
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**attribute** | **Set<String>** | Object one attribute enum | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/lib/openapi.dart

@@ -51,7 +51,10 @@ export 'package:openapi/src/model/model_return.dart';
 export 'package:openapi/src/model/name.dart';
 export 'package:openapi/src/model/nullable_class.dart';
 export 'package:openapi/src/model/number_only.dart';
+export 'package:openapi/src/model/object_that_references_objects_with_duplicate_inline_enums.dart';
 export 'package:openapi/src/model/object_with_deprecated_fields.dart';
+export 'package:openapi/src/model/object_with_duplicate_inline_enum.dart';
+export 'package:openapi/src/model/object_with_inline_enum.dart';
 export 'package:openapi/src/model/order.dart';
 export 'package:openapi/src/model/outer_composite.dart';
 export 'package:openapi/src/model/outer_enum.dart';

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/lib/src/api/fake_api.dart

@@ -15,6 +15,7 @@ import 'package:openapi/src/model/file_schema_test_class.dart';
 import 'package:openapi/src/model/health_check_result.dart';
 import 'package:openapi/src/model/model_client.dart';
 import 'package:openapi/src/model/model_enum_class.dart';
+import 'package:openapi/src/model/object_that_references_objects_with_duplicate_inline_enums.dart';
 import 'package:openapi/src/model/outer_composite.dart';
 import 'package:openapi/src/model/outer_object_with_enum_property.dart';
 import 'package:openapi/src/model/pet.dart';
@@ -97,6 +98,76 @@ _responseData = rawData == null ? null : deserialize<FakeBigDecimalMap200Respons
     );
   }
 
+  /// test objects with duplicate inline enums see issue# 21582
+  /// 
+  ///
+  /// Parameters:
+  /// * [cancelToken] - A [CancelToken] that can be used to cancel the operation
+  /// * [headers] - Can be used to add additional headers to the request
+  /// * [extras] - Can be used to add flags to the request
+  /// * [validateStatus] - A [ValidateStatus] callback that can be used to determine request success based on the HTTP status of the response
+  /// * [onSendProgress] - A [ProgressCallback] that can be used to get the send progress
+  /// * [onReceiveProgress] - A [ProgressCallback] that can be used to get the receive progress
+  ///
+  /// Returns a [Future] containing a [Response] with a [ObjectThatReferencesObjectsWithDuplicateInlineEnums] as data
+  /// Throws [DioException] if API call or serialization fails
+  Future<Response<ObjectThatReferencesObjectsWithDuplicateInlineEnums>> fakeDuplicateInlineEnum({ 
+    CancelToken? cancelToken,
+    Map<String, dynamic>? headers,
+    Map<String, dynamic>? extra,
+    ValidateStatus? validateStatus,
+    ProgressCallback? onSendProgress,
+    ProgressCallback? onReceiveProgress,
+  }) async {
+    final _path = r'/fake/duplicate-inline-enums';
+    final _options = Options(
+      method: r'GET',
+      headers: <String, dynamic>{
+        ...?headers,
+      },
+      extra: <String, dynamic>{
+        'secure': <Map<String, String>>[],
+        ...?extra,
+      },
+      validateStatus: validateStatus,
+    );
+
+    final _response = await _dio.request<Object>(
+      _path,
+      options: _options,
+      cancelToken: cancelToken,
+      onSendProgress: onSendProgress,
+      onReceiveProgress: onReceiveProgress,
+    );
+
+    ObjectThatReferencesObjectsWithDuplicateInlineEnums? _responseData;
+
+    try {
+final rawData = _response.data;
+_responseData = rawData == null ? null : deserialize<ObjectThatReferencesObjectsWithDuplicateInlineEnums, ObjectThatReferencesObjectsWithDuplicateInlineEnums>(rawData, 'ObjectThatReferencesObjectsWithDuplicateInlineEnums', growable: true);
+
+    } catch (error, stackTrace) {
+      throw DioException(
+        requestOptions: _response.requestOptions,
+        response: _response,
+        type: DioExceptionType.unknown,
+        error: error,
+        stackTrace: stackTrace,
+      );
+    }
+
+    return Response<ObjectThatReferencesObjectsWithDuplicateInlineEnums>(
+      data: _responseData,
+      headers: _response.headers,
+      isRedirect: _response.isRedirect,
+      requestOptions: _response.requestOptions,
+      redirects: _response.redirects,
+      statusCode: _response.statusCode,
+      statusMessage: _response.statusMessage,
+      extra: _response.extra,
+    );
+  }
+
   /// Health check endpoint
   /// 
   ///

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/lib/src/deserialize.dart

@@ -31,7 +31,10 @@ import 'package:openapi/src/model/model_return.dart';
 import 'package:openapi/src/model/name.dart';
 import 'package:openapi/src/model/nullable_class.dart';
 import 'package:openapi/src/model/number_only.dart';
+import 'package:openapi/src/model/object_that_references_objects_with_duplicate_inline_enums.dart';
 import 'package:openapi/src/model/object_with_deprecated_fields.dart';
+import 'package:openapi/src/model/object_with_duplicate_inline_enum.dart';
+import 'package:openapi/src/model/object_with_inline_enum.dart';
 import 'package:openapi/src/model/order.dart';
 import 'package:openapi/src/model/outer_composite.dart';
 import 'package:openapi/src/model/outer_object_with_enum_property.dart';
@@ -131,8 +134,14 @@ final _regMap = RegExp(r'^Map<String,(.*)>$');
           return NullableClass.fromJson(value as Map<String, dynamic>) as ReturnType;
         case 'NumberOnly':
           return NumberOnly.fromJson(value as Map<String, dynamic>) as ReturnType;
+        case 'ObjectThatReferencesObjectsWithDuplicateInlineEnums':
+          return ObjectThatReferencesObjectsWithDuplicateInlineEnums.fromJson(value as Map<String, dynamic>) as ReturnType;
         case 'ObjectWithDeprecatedFields':
           return ObjectWithDeprecatedFields.fromJson(value as Map<String, dynamic>) as ReturnType;
+        case 'ObjectWithDuplicateInlineEnum':
+          return ObjectWithDuplicateInlineEnum.fromJson(value as Map<String, dynamic>) as ReturnType;
+        case 'ObjectWithInlineEnum':
+          return ObjectWithInlineEnum.fromJson(value as Map<String, dynamic>) as ReturnType;
         case 'Order':
           return Order.fromJson(value as Map<String, dynamic>) as ReturnType;
         case 'OuterComposite':

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/lib/src/model/object_that_references_objects_with_duplicate_inline_enums.dart

@@ -0,0 +1,76 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+
+// ignore_for_file: unused_element
+import 'package:openapi/src/model/object_with_duplicate_inline_enum.dart';
+import 'package:openapi/src/model/object_with_inline_enum.dart';
+import 'package:copy_with_extension/copy_with_extension.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'object_that_references_objects_with_duplicate_inline_enums.g.dart';
+
+
+@CopyWith()
+@JsonSerializable(
+  checked: true,
+  createToJson: true,
+  disallowUnrecognizedKeys: false,
+  explicitToJson: true,
+)
+class ObjectThatReferencesObjectsWithDuplicateInlineEnums {
+  /// Returns a new [ObjectThatReferencesObjectsWithDuplicateInlineEnums] instance.
+  ObjectThatReferencesObjectsWithDuplicateInlineEnums({
+
+     this.objectOne,
+
+     this.objectTwo,
+  });
+
+  @JsonKey(
+    
+    name: r'object_one',
+    required: false,
+    includeIfNull: false,
+  )
+
+
+  final ObjectWithInlineEnum? objectOne;
+
+
+
+  @JsonKey(
+    
+    name: r'object_two',
+    required: false,
+    includeIfNull: false,
+  )
+
+
+  final ObjectWithDuplicateInlineEnum? objectTwo;
+
+
+
+
+
+    @override
+    bool operator ==(Object other) => identical(this, other) || other is ObjectThatReferencesObjectsWithDuplicateInlineEnums &&
+      other.objectOne == objectOne &&
+      other.objectTwo == objectTwo;
+
+    @override
+    int get hashCode =>
+        objectOne.hashCode +
+        objectTwo.hashCode;
+
+  factory ObjectThatReferencesObjectsWithDuplicateInlineEnums.fromJson(Map<String, dynamic> json) => _$ObjectThatReferencesObjectsWithDuplicateInlineEnumsFromJson(json);
+
+  Map<String, dynamic> toJson() => _$ObjectThatReferencesObjectsWithDuplicateInlineEnumsToJson(this);
+
+  @override
+  String toString() {
+    return toJson().toString();
+  }
+
+}
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/lib/src/model/object_with_duplicate_inline_enum.dart

@@ -0,0 +1,78 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+
+// ignore_for_file: unused_element
+import 'package:copy_with_extension/copy_with_extension.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'object_with_duplicate_inline_enum.g.dart';
+
+
+@CopyWith()
+@JsonSerializable(
+  checked: true,
+  createToJson: true,
+  disallowUnrecognizedKeys: false,
+  explicitToJson: true,
+)
+class ObjectWithDuplicateInlineEnum {
+  /// Returns a new [ObjectWithDuplicateInlineEnum] instance.
+  ObjectWithDuplicateInlineEnum({
+
+     this.attribute,
+  });
+
+      /// Object two attribute enum
+  @JsonKey(
+    
+    name: r'attribute',
+    required: false,
+    includeIfNull: false,
+  unknownEnumValue: Set<ObjectWithDuplicateInlineEnumAttributeEnum>.unknownDefaultOpenApi,
+  )
+
+
+  final Set<ObjectWithDuplicateInlineEnumAttributeEnum>? attribute;
+
+
+
+
+
+    @override
+    bool operator ==(Object other) => identical(this, other) || other is ObjectWithDuplicateInlineEnum &&
+      other.attribute == attribute;
+
+    @override
+    int get hashCode =>
+        attribute.hashCode;
+
+  factory ObjectWithDuplicateInlineEnum.fromJson(Map<String, dynamic> json) => _$ObjectWithDuplicateInlineEnumFromJson(json);
+
+  Map<String, dynamic> toJson() => _$ObjectWithDuplicateInlineEnumToJson(this);
+
+  @override
+  String toString() {
+    return toJson().toString();
+  }
+
+}
+
+
+enum ObjectWithDuplicateInlineEnumAttributeEnum {
+@JsonValue(r'value_one')
+valueOne(r'value_one'),
+@JsonValue(r'value_two')
+valueTwo(r'value_two'),
+@JsonValue(r'unknown_default_open_api')
+unknownDefaultOpenApi(r'unknown_default_open_api');
+
+const ObjectWithDuplicateInlineEnumAttributeEnum(this.value);
+
+final String value;
+
+@override
+String toString() => value;
+}
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/lib/src/model/object_with_inline_enum.dart

@@ -0,0 +1,78 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+
+// ignore_for_file: unused_element
+import 'package:copy_with_extension/copy_with_extension.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'object_with_inline_enum.g.dart';
+
+
+@CopyWith()
+@JsonSerializable(
+  checked: true,
+  createToJson: true,
+  disallowUnrecognizedKeys: false,
+  explicitToJson: true,
+)
+class ObjectWithInlineEnum {
+  /// Returns a new [ObjectWithInlineEnum] instance.
+  ObjectWithInlineEnum({
+
+     this.attribute,
+  });
+
+      /// Object one attribute enum
+  @JsonKey(
+    
+    name: r'attribute',
+    required: false,
+    includeIfNull: false,
+  unknownEnumValue: Set<ObjectWithInlineEnumAttributeEnum>.unknownDefaultOpenApi,
+  )
+
+
+  final Set<ObjectWithInlineEnumAttributeEnum>? attribute;
+
+
+
+
+
+    @override
+    bool operator ==(Object other) => identical(this, other) || other is ObjectWithInlineEnum &&
+      other.attribute == attribute;
+
+    @override
+    int get hashCode =>
+        attribute.hashCode;
+
+  factory ObjectWithInlineEnum.fromJson(Map<String, dynamic> json) => _$ObjectWithInlineEnumFromJson(json);
+
+  Map<String, dynamic> toJson() => _$ObjectWithInlineEnumToJson(this);
+
+  @override
+  String toString() {
+    return toJson().toString();
+  }
+
+}
+
+
+enum ObjectWithInlineEnumAttributeEnum {
+@JsonValue(r'value_one')
+valueOne(r'value_one'),
+@JsonValue(r'value_two')
+valueTwo(r'value_two'),
+@JsonValue(r'unknown_default_open_api')
+unknownDefaultOpenApi(r'unknown_default_open_api');
+
+const ObjectWithInlineEnumAttributeEnum(this.value);
+
+final String value;
+
+@override
+String toString() => value;
+}
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/test/object_that_references_objects_with_duplicate_inline_enums_test.dart

@@ -0,0 +1,21 @@
+import 'package:test/test.dart';
+import 'package:openapi/openapi.dart';
+
+// tests for ObjectThatReferencesObjectsWithDuplicateInlineEnums
+void main() {
+  final ObjectThatReferencesObjectsWithDuplicateInlineEnums? instance = /* ObjectThatReferencesObjectsWithDuplicateInlineEnums(...) */ null;
+  // TODO add properties to the entity
+
+  group(ObjectThatReferencesObjectsWithDuplicateInlineEnums, () {
+    // ObjectWithInlineEnum objectOne
+    test('to test the property `objectOne`', () async {
+      // TODO
+    });
+
+    // ObjectWithDuplicateInlineEnum objectTwo
+    test('to test the property `objectTwo`', () async {
+      // TODO
+    });
+
+  });
+}

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/test/object_with_duplicate_inline_enum_test.dart

@@ -0,0 +1,17 @@
+import 'package:test/test.dart';
+import 'package:openapi/openapi.dart';
+
+// tests for ObjectWithDuplicateInlineEnum
+void main() {
+  final ObjectWithDuplicateInlineEnum? instance = /* ObjectWithDuplicateInlineEnum(...) */ null;
+  // TODO add properties to the entity
+
+  group(ObjectWithDuplicateInlineEnum, () {
+    // Object two attribute enum
+    // Set<String> attribute
+    test('to test the property `attribute`', () async {
+      // TODO
+    });
+
+  });
+}

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake-json_serializable/test/object_with_inline_enum_test.dart

@@ -0,0 +1,17 @@
+import 'package:test/test.dart';
+import 'package:openapi/openapi.dart';
+
+// tests for ObjectWithInlineEnum
+void main() {
+  final ObjectWithInlineEnum? instance = /* ObjectWithInlineEnum(...) */ null;
+  // TODO add properties to the entity
+
+  group(ObjectWithInlineEnum, () {
+    // Object one attribute enum
+    // Set<String> attribute
+    test('to test the property `attribute`', () async {
+      // TODO
+    });
+
+  });
+}

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/.openapi-generator/FILES

@@ -39,7 +39,10 @@ doc/ModelReturn.md
 doc/Name.md
 doc/NullableClass.md
 doc/NumberOnly.md
+doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md
 doc/ObjectWithDeprecatedFields.md
+doc/ObjectWithDuplicateInlineEnum.md
+doc/ObjectWithInlineEnum.md
 doc/Order.md
 doc/OuterComposite.md
 doc/OuterEnum.md
@@ -111,7 +114,10 @@ lib/src/model/model_return.dart
 lib/src/model/name.dart
 lib/src/model/nullable_class.dart
 lib/src/model/number_only.dart
+lib/src/model/object_that_references_objects_with_duplicate_inline_enums.dart
 lib/src/model/object_with_deprecated_fields.dart
+lib/src/model/object_with_duplicate_inline_enum.dart
+lib/src/model/object_with_inline_enum.dart
 lib/src/model/order.dart
 lib/src/model/outer_composite.dart
 lib/src/model/outer_enum.dart

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/README.md

@@ -68,6 +68,7 @@ Class | Method | HTTP request | Description
 [*AnotherFakeApi*](doc/AnotherFakeApi.md) | [**call123testSpecialTags**](doc/AnotherFakeApi.md#call123testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
 [*DefaultApi*](doc/DefaultApi.md) | [**fooGet**](doc/DefaultApi.md#fooget) | **GET** /foo | 
 [*FakeApi*](doc/FakeApi.md) | [**fakeBigDecimalMap**](doc/FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+[*FakeApi*](doc/FakeApi.md) | [**fakeDuplicateInlineEnum**](doc/FakeApi.md#fakeduplicateinlineenum) | **GET** /fake/duplicate-inline-enums | test objects with duplicate inline enums see issue# 21582
 [*FakeApi*](doc/FakeApi.md) | [**fakeHealthGet**](doc/FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 [*FakeApi*](doc/FakeApi.md) | [**fakeHttpSignatureTest**](doc/FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 [*FakeApi*](doc/FakeApi.md) | [**fakeOuterBooleanSerialize**](doc/FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
@@ -149,7 +150,10 @@ Class | Method | HTTP request | Description
  - [Name](doc/Name.md)
  - [NullableClass](doc/NullableClass.md)
  - [NumberOnly](doc/NumberOnly.md)
+ - [ObjectThatReferencesObjectsWithDuplicateInlineEnums](doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md)
  - [ObjectWithDeprecatedFields](doc/ObjectWithDeprecatedFields.md)
+ - [ObjectWithDuplicateInlineEnum](doc/ObjectWithDuplicateInlineEnum.md)
+ - [ObjectWithInlineEnum](doc/ObjectWithInlineEnum.md)
  - [Order](doc/Order.md)
  - [OuterComposite](doc/OuterComposite.md)
  - [OuterEnum](doc/OuterEnum.md)

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/doc/FakeApi.md

@@ -10,6 +10,7 @@ All URIs are relative to *http://petstore.swagger.io:80/v2*
 Method | HTTP request | Description
 ------------- | ------------- | -------------
 [**fakeBigDecimalMap**](FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+[**fakeDuplicateInlineEnum**](FakeApi.md#fakeduplicateinlineenum) | **GET** /fake/duplicate-inline-enums | test objects with duplicate inline enums see issue# 21582
 [**fakeHealthGet**](FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 [**fakeHttpSignatureTest**](FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 [**fakeOuterBooleanSerialize**](FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
@@ -72,6 +73,43 @@ No authorization required
 
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
+# **fakeDuplicateInlineEnum**
+> ObjectThatReferencesObjectsWithDuplicateInlineEnums fakeDuplicateInlineEnum()
+
+test objects with duplicate inline enums see issue# 21582
+
+### Example
+```dart
+import 'package:openapi/api.dart';
+
+final api = Openapi().getFakeApi();
+
+try {
+    final response = api.fakeDuplicateInlineEnum();
+    print(response);
+} catch on DioException (e) {
+    print('Exception when calling FakeApi->fakeDuplicateInlineEnum: $e\n');
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+[**ObjectThatReferencesObjectsWithDuplicateInlineEnums**](ObjectThatReferencesObjectsWithDuplicateInlineEnums.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
 # **fakeHealthGet**
 > HealthCheckResult fakeHealthGet()
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md

@@ -0,0 +1,16 @@
+# openapi.model.ObjectThatReferencesObjectsWithDuplicateInlineEnums
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**objectOne** | [**ObjectWithInlineEnum**](ObjectWithInlineEnum.md) |  | [optional] 
+**objectTwo** | [**ObjectWithDuplicateInlineEnum**](ObjectWithDuplicateInlineEnum.md) |  | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/doc/ObjectWithDuplicateInlineEnum.md

@@ -0,0 +1,15 @@
+# openapi.model.ObjectWithDuplicateInlineEnum
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**attribute** | **BuiltSet<String>** | Object two attribute enum | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/doc/ObjectWithInlineEnum.md

@@ -0,0 +1,15 @@
+# openapi.model.ObjectWithInlineEnum
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**attribute** | **BuiltSet<String>** | Object one attribute enum | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/openapi.dart

@@ -52,7 +52,10 @@ export 'package:openapi/src/model/model_return.dart';
 export 'package:openapi/src/model/name.dart';
 export 'package:openapi/src/model/nullable_class.dart';
 export 'package:openapi/src/model/number_only.dart';
+export 'package:openapi/src/model/object_that_references_objects_with_duplicate_inline_enums.dart';
 export 'package:openapi/src/model/object_with_deprecated_fields.dart';
+export 'package:openapi/src/model/object_with_duplicate_inline_enum.dart';
+export 'package:openapi/src/model/object_with_inline_enum.dart';
 export 'package:openapi/src/model/order.dart';
 export 'package:openapi/src/model/outer_composite.dart';
 export 'package:openapi/src/model/outer_enum.dart';

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/api/fake_api.dart

@@ -19,6 +19,7 @@ import 'package:openapi/src/model/file_schema_test_class.dart';
 import 'package:openapi/src/model/health_check_result.dart';
 import 'package:openapi/src/model/model_client.dart';
 import 'package:openapi/src/model/model_enum_class.dart';
+import 'package:openapi/src/model/object_that_references_objects_with_duplicate_inline_enums.dart';
 import 'package:openapi/src/model/outer_composite.dart';
 import 'package:openapi/src/model/outer_object_with_enum_property.dart';
 import 'package:openapi/src/model/pet.dart';
@@ -106,6 +107,79 @@ class FakeApi {
     );
   }
 
+  /// test objects with duplicate inline enums see issue# 21582
+  /// 
+  ///
+  /// Parameters:
+  /// * [cancelToken] - A [CancelToken] that can be used to cancel the operation
+  /// * [headers] - Can be used to add additional headers to the request
+  /// * [extras] - Can be used to add flags to the request
+  /// * [validateStatus] - A [ValidateStatus] callback that can be used to determine request success based on the HTTP status of the response
+  /// * [onSendProgress] - A [ProgressCallback] that can be used to get the send progress
+  /// * [onReceiveProgress] - A [ProgressCallback] that can be used to get the receive progress
+  ///
+  /// Returns a [Future] containing a [Response] with a [ObjectThatReferencesObjectsWithDuplicateInlineEnums] as data
+  /// Throws [DioException] if API call or serialization fails
+  Future<Response<ObjectThatReferencesObjectsWithDuplicateInlineEnums>> fakeDuplicateInlineEnum({ 
+    CancelToken? cancelToken,
+    Map<String, dynamic>? headers,
+    Map<String, dynamic>? extra,
+    ValidateStatus? validateStatus,
+    ProgressCallback? onSendProgress,
+    ProgressCallback? onReceiveProgress,
+  }) async {
+    final _path = r'/fake/duplicate-inline-enums';
+    final _options = Options(
+      method: r'GET',
+      headers: <String, dynamic>{
+        ...?headers,
+      },
+      extra: <String, dynamic>{
+        'secure': <Map<String, String>>[],
+        ...?extra,
+      },
+      validateStatus: validateStatus,
+    );
+
+    final _response = await _dio.request<Object>(
+      _path,
+      options: _options,
+      cancelToken: cancelToken,
+      onSendProgress: onSendProgress,
+      onReceiveProgress: onReceiveProgress,
+    );
+
+    ObjectThatReferencesObjectsWithDuplicateInlineEnums? _responseData;
+
+    try {
+      final rawResponse = _response.data;
+      _responseData = rawResponse == null ? null : _serializers.deserialize(
+        rawResponse,
+        specifiedType: const FullType(ObjectThatReferencesObjectsWithDuplicateInlineEnums),
+      ) as ObjectThatReferencesObjectsWithDuplicateInlineEnums;
+
+    } catch (error, stackTrace) {
+      throw DioException(
+        requestOptions: _response.requestOptions,
+        response: _response,
+        type: DioExceptionType.unknown,
+        error: error,
+        stackTrace: stackTrace,
+      );
+    }
+
+    return Response<ObjectThatReferencesObjectsWithDuplicateInlineEnums>(
+      data: _responseData,
+      headers: _response.headers,
+      isRedirect: _response.isRedirect,
+      requestOptions: _response.requestOptions,
+      redirects: _response.redirects,
+      statusCode: _response.statusCode,
+      statusMessage: _response.statusMessage,
+      extra: _response.extra,
+    );
+  }
+
   /// Health check endpoint
   /// 
   ///

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/model/object_that_references_objects_with_duplicate_inline_enums.dart

@@ -0,0 +1,128 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+
+// ignore_for_file: unused_element
+import 'package:openapi/src/model/object_with_duplicate_inline_enum.dart';
+import 'package:openapi/src/model/object_with_inline_enum.dart';
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'object_that_references_objects_with_duplicate_inline_enums.g.dart';
+
+/// ObjectThatReferencesObjectsWithDuplicateInlineEnums
+///
+/// Properties:
+/// * [objectOne] 
+/// * [objectTwo] 
+@BuiltValue()
+abstract class ObjectThatReferencesObjectsWithDuplicateInlineEnums implements Built<ObjectThatReferencesObjectsWithDuplicateInlineEnums, ObjectThatReferencesObjectsWithDuplicateInlineEnumsBuilder> {
+  @BuiltValueField(wireName: r'object_one')
+  ObjectWithInlineEnum? get objectOne;
+
+  @BuiltValueField(wireName: r'object_two')
+  ObjectWithDuplicateInlineEnum? get objectTwo;
+
+  ObjectThatReferencesObjectsWithDuplicateInlineEnums._();
+
+  factory ObjectThatReferencesObjectsWithDuplicateInlineEnums([void updates(ObjectThatReferencesObjectsWithDuplicateInlineEnumsBuilder b)]) = _$ObjectThatReferencesObjectsWithDuplicateInlineEnums;
+
+  @BuiltValueHook(initializeBuilder: true)
+  static void _defaults(ObjectThatReferencesObjectsWithDuplicateInlineEnumsBuilder b) => b;
+
+  @BuiltValueSerializer(custom: true)
+  static Serializer<ObjectThatReferencesObjectsWithDuplicateInlineEnums> get serializer => _$ObjectThatReferencesObjectsWithDuplicateInlineEnumsSerializer();
+}
+
+class _$ObjectThatReferencesObjectsWithDuplicateInlineEnumsSerializer implements PrimitiveSerializer<ObjectThatReferencesObjectsWithDuplicateInlineEnums> {
+  @override
+  final Iterable<Type> types = const [ObjectThatReferencesObjectsWithDuplicateInlineEnums, _$ObjectThatReferencesObjectsWithDuplicateInlineEnums];
+
+  @override
+  final String wireName = r'ObjectThatReferencesObjectsWithDuplicateInlineEnums';
+
+  Iterable<Object?> _serializeProperties(
+    Serializers serializers,
+    ObjectThatReferencesObjectsWithDuplicateInlineEnums object, {
+    FullType specifiedType = FullType.unspecified,
+  }) sync* {
+    if (object.objectOne != null) {
+      yield r'object_one';
+      yield serializers.serialize(
+        object.objectOne,
+        specifiedType: const FullType(ObjectWithInlineEnum),
+      );
+    }
+    if (object.objectTwo != null) {
+      yield r'object_two';
+      yield serializers.serialize(
+        object.objectTwo,
+        specifiedType: const FullType(ObjectWithDuplicateInlineEnum),
+      );
+    }
+  }
+
+  @override
+  Object serialize(
+    Serializers serializers,
+    ObjectThatReferencesObjectsWithDuplicateInlineEnums object, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    return _serializeProperties(serializers, object, specifiedType: specifiedType).toList();
+  }
+
+  void _deserializeProperties(
+    Serializers serializers,
+    Object serialized, {
+    FullType specifiedType = FullType.unspecified,
+    required List<Object?> serializedList,
+    required ObjectThatReferencesObjectsWithDuplicateInlineEnumsBuilder result,
+    required List<Object?> unhandled,
+  }) {
+    for (var i = 0; i < serializedList.length; i += 2) {
+      final key = serializedList[i] as String;
+      final value = serializedList[i + 1];
+      switch (key) {
+        case r'object_one':
+          final valueDes = serializers.deserialize(
+            value,
+            specifiedType: const FullType(ObjectWithInlineEnum),
+          ) as ObjectWithInlineEnum;
+          result.objectOne.replace(valueDes);
+          break;
+        case r'object_two':
+          final valueDes = serializers.deserialize(
+            value,
+            specifiedType: const FullType(ObjectWithDuplicateInlineEnum),
+          ) as ObjectWithDuplicateInlineEnum;
+          result.objectTwo.replace(valueDes);
+          break;
+        default:
+          unhandled.add(key);
+          unhandled.add(value);
+          break;
+      }
+    }
+  }
+
+  @override
+  ObjectThatReferencesObjectsWithDuplicateInlineEnums deserialize(
+    Serializers serializers,
+    Object serialized, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    final result = ObjectThatReferencesObjectsWithDuplicateInlineEnumsBuilder();
+    final serializedList = (serialized as Iterable<Object?>).toList();
+    final unhandled = <Object?>[];
+    _deserializeProperties(
+      serializers,
+      serialized,
+      specifiedType: specifiedType,
+      serializedList: serializedList,
+      unhandled: unhandled,
+      result: result,
+    );
+    return result.build();
+  }
+}
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/model/object_with_duplicate_inline_enum.dart

@@ -0,0 +1,128 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+
+// ignore_for_file: unused_element
+import 'package:built_collection/built_collection.dart';
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'object_with_duplicate_inline_enum.g.dart';
+
+/// ObjectWithDuplicateInlineEnum
+///
+/// Properties:
+/// * [attribute] - Object two attribute enum
+@BuiltValue()
+abstract class ObjectWithDuplicateInlineEnum implements Built<ObjectWithDuplicateInlineEnum, ObjectWithDuplicateInlineEnumBuilder> {
+  /// Object two attribute enum
+  @BuiltValueField(wireName: r'attribute')
+  BuiltSet<ObjectWithDuplicateInlineEnumAttributeEnum>? get attribute;
+  // enum attributeEnum {  value_one,  value_two,  };
+
+  ObjectWithDuplicateInlineEnum._();
+
+  factory ObjectWithDuplicateInlineEnum([void updates(ObjectWithDuplicateInlineEnumBuilder b)]) = _$ObjectWithDuplicateInlineEnum;
+
+  @BuiltValueHook(initializeBuilder: true)
+  static void _defaults(ObjectWithDuplicateInlineEnumBuilder b) => b;
+
+  @BuiltValueSerializer(custom: true)
+  static Serializer<ObjectWithDuplicateInlineEnum> get serializer => _$ObjectWithDuplicateInlineEnumSerializer();
+}
+
+class _$ObjectWithDuplicateInlineEnumSerializer implements PrimitiveSerializer<ObjectWithDuplicateInlineEnum> {
+  @override
+  final Iterable<Type> types = const [ObjectWithDuplicateInlineEnum, _$ObjectWithDuplicateInlineEnum];
+
+  @override
+  final String wireName = r'ObjectWithDuplicateInlineEnum';
+
+  Iterable<Object?> _serializeProperties(
+    Serializers serializers,
+    ObjectWithDuplicateInlineEnum object, {
+    FullType specifiedType = FullType.unspecified,
+  }) sync* {
+    if (object.attribute != null) {
+      yield r'attribute';
+      yield serializers.serialize(
+        object.attribute,
+        specifiedType: const FullType(BuiltSet, [FullType(ObjectWithDuplicateInlineEnumAttributeEnum)]),
+      );
+    }
+  }
+
+  @override
+  Object serialize(
+    Serializers serializers,
+    ObjectWithDuplicateInlineEnum object, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    return _serializeProperties(serializers, object, specifiedType: specifiedType).toList();
+  }
+
+  void _deserializeProperties(
+    Serializers serializers,
+    Object serialized, {
+    FullType specifiedType = FullType.unspecified,
+    required List<Object?> serializedList,
+    required ObjectWithDuplicateInlineEnumBuilder result,
+    required List<Object?> unhandled,
+  }) {
+    for (var i = 0; i < serializedList.length; i += 2) {
+      final key = serializedList[i] as String;
+      final value = serializedList[i + 1];
+      switch (key) {
+        case r'attribute':
+          final valueDes = serializers.deserialize(
+            value,
+            specifiedType: const FullType(BuiltSet, [FullType(ObjectWithDuplicateInlineEnumAttributeEnum)]),
+          ) as BuiltSet<ObjectWithDuplicateInlineEnumAttributeEnum>;
+          result.attribute.replace(valueDes);
+          break;
+        default:
+          unhandled.add(key);
+          unhandled.add(value);
+          break;
+      }
+    }
+  }
+
+  @override
+  ObjectWithDuplicateInlineEnum deserialize(
+    Serializers serializers,
+    Object serialized, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    final result = ObjectWithDuplicateInlineEnumBuilder();
+    final serializedList = (serialized as Iterable<Object?>).toList();
+    final unhandled = <Object?>[];
+    _deserializeProperties(
+      serializers,
+      serialized,
+      specifiedType: specifiedType,
+      serializedList: serializedList,
+      unhandled: unhandled,
+      result: result,
+    );
+    return result.build();
+  }
+}
+
+class ObjectWithDuplicateInlineEnumAttributeEnum extends EnumClass {
+
+  @BuiltValueEnumConst(wireName: r'value_one')
+  static const ObjectWithDuplicateInlineEnumAttributeEnum valueOne = _$objectWithDuplicateInlineEnumAttributeEnum_valueOne;
+  @BuiltValueEnumConst(wireName: r'value_two')
+  static const ObjectWithDuplicateInlineEnumAttributeEnum valueTwo = _$objectWithDuplicateInlineEnumAttributeEnum_valueTwo;
+  @BuiltValueEnumConst(wireName: r'unknown_default_open_api', fallback: true)
+  static const ObjectWithDuplicateInlineEnumAttributeEnum unknownDefaultOpenApi = _$objectWithDuplicateInlineEnumAttributeEnum_unknownDefaultOpenApi;
+
+  static Serializer<ObjectWithDuplicateInlineEnumAttributeEnum> get serializer => _$objectWithDuplicateInlineEnumAttributeEnumSerializer;
+
+  const ObjectWithDuplicateInlineEnumAttributeEnum._(String name): super(name);
+
+  static BuiltSet<ObjectWithDuplicateInlineEnumAttributeEnum> get values => _$objectWithDuplicateInlineEnumAttributeEnumValues;
+  static ObjectWithDuplicateInlineEnumAttributeEnum valueOf(String name) => _$objectWithDuplicateInlineEnumAttributeEnumValueOf(name);
+}
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/model/object_with_inline_enum.dart

@@ -0,0 +1,128 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+
+// ignore_for_file: unused_element
+import 'package:built_collection/built_collection.dart';
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'object_with_inline_enum.g.dart';
+
+/// ObjectWithInlineEnum
+///
+/// Properties:
+/// * [attribute] - Object one attribute enum
+@BuiltValue()
+abstract class ObjectWithInlineEnum implements Built<ObjectWithInlineEnum, ObjectWithInlineEnumBuilder> {
+  /// Object one attribute enum
+  @BuiltValueField(wireName: r'attribute')
+  BuiltSet<ObjectWithInlineEnumAttributeEnum>? get attribute;
+  // enum attributeEnum {  value_one,  value_two,  };
+
+  ObjectWithInlineEnum._();
+
+  factory ObjectWithInlineEnum([void updates(ObjectWithInlineEnumBuilder b)]) = _$ObjectWithInlineEnum;
+
+  @BuiltValueHook(initializeBuilder: true)
+  static void _defaults(ObjectWithInlineEnumBuilder b) => b;
+
+  @BuiltValueSerializer(custom: true)
+  static Serializer<ObjectWithInlineEnum> get serializer => _$ObjectWithInlineEnumSerializer();
+}
+
+class _$ObjectWithInlineEnumSerializer implements PrimitiveSerializer<ObjectWithInlineEnum> {
+  @override
+  final Iterable<Type> types = const [ObjectWithInlineEnum, _$ObjectWithInlineEnum];
+
+  @override
+  final String wireName = r'ObjectWithInlineEnum';
+
+  Iterable<Object?> _serializeProperties(
+    Serializers serializers,
+    ObjectWithInlineEnum object, {
+    FullType specifiedType = FullType.unspecified,
+  }) sync* {
+    if (object.attribute != null) {
+      yield r'attribute';
+      yield serializers.serialize(
+        object.attribute,
+        specifiedType: const FullType(BuiltSet, [FullType(ObjectWithInlineEnumAttributeEnum)]),
+      );
+    }
+  }
+
+  @override
+  Object serialize(
+    Serializers serializers,
+    ObjectWithInlineEnum object, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    return _serializeProperties(serializers, object, specifiedType: specifiedType).toList();
+  }
+
+  void _deserializeProperties(
+    Serializers serializers,
+    Object serialized, {
+    FullType specifiedType = FullType.unspecified,
+    required List<Object?> serializedList,
+    required ObjectWithInlineEnumBuilder result,
+    required List<Object?> unhandled,
+  }) {
+    for (var i = 0; i < serializedList.length; i += 2) {
+      final key = serializedList[i] as String;
+      final value = serializedList[i + 1];
+      switch (key) {
+        case r'attribute':
+          final valueDes = serializers.deserialize(
+            value,
+            specifiedType: const FullType(BuiltSet, [FullType(ObjectWithInlineEnumAttributeEnum)]),
+          ) as BuiltSet<ObjectWithInlineEnumAttributeEnum>;
+          result.attribute.replace(valueDes);
+          break;
+        default:
+          unhandled.add(key);
+          unhandled.add(value);
+          break;
+      }
+    }
+  }
+
+  @override
+  ObjectWithInlineEnum deserialize(
+    Serializers serializers,
+    Object serialized, {
+    FullType specifiedType = FullType.unspecified,
+  }) {
+    final result = ObjectWithInlineEnumBuilder();
+    final serializedList = (serialized as Iterable<Object?>).toList();
+    final unhandled = <Object?>[];
+    _deserializeProperties(
+      serializers,
+      serialized,
+      specifiedType: specifiedType,
+      serializedList: serializedList,
+      unhandled: unhandled,
+      result: result,
+    );
+    return result.build();
+  }
+}
+
+class ObjectWithInlineEnumAttributeEnum extends EnumClass {
+
+  @BuiltValueEnumConst(wireName: r'value_one')
+  static const ObjectWithInlineEnumAttributeEnum valueOne = _$objectWithInlineEnumAttributeEnum_valueOne;
+  @BuiltValueEnumConst(wireName: r'value_two')
+  static const ObjectWithInlineEnumAttributeEnum valueTwo = _$objectWithInlineEnumAttributeEnum_valueTwo;
+  @BuiltValueEnumConst(wireName: r'unknown_default_open_api', fallback: true)
+  static const ObjectWithInlineEnumAttributeEnum unknownDefaultOpenApi = _$objectWithInlineEnumAttributeEnum_unknownDefaultOpenApi;
+
+  static Serializer<ObjectWithInlineEnumAttributeEnum> get serializer => _$objectWithInlineEnumAttributeEnumSerializer;
+
+  const ObjectWithInlineEnumAttributeEnum._(String name): super(name);
+
+  static BuiltSet<ObjectWithInlineEnumAttributeEnum> get values => _$objectWithInlineEnumAttributeEnumValues;
+  static ObjectWithInlineEnumAttributeEnum valueOf(String name) => _$objectWithInlineEnumAttributeEnumValueOf(name);
+}
+

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/src/serializers.dart

@@ -48,7 +48,10 @@ import 'package:openapi/src/model/model_return.dart';
 import 'package:openapi/src/model/name.dart';
 import 'package:openapi/src/model/nullable_class.dart';
 import 'package:openapi/src/model/number_only.dart';
+import 'package:openapi/src/model/object_that_references_objects_with_duplicate_inline_enums.dart';
 import 'package:openapi/src/model/object_with_deprecated_fields.dart';
+import 'package:openapi/src/model/object_with_duplicate_inline_enum.dart';
+import 'package:openapi/src/model/object_with_inline_enum.dart';
 import 'package:openapi/src/model/order.dart';
 import 'package:openapi/src/model/outer_composite.dart';
 import 'package:openapi/src/model/outer_enum.dart';
@@ -104,7 +107,10 @@ part 'serializers.g.dart';
   Name,
   NullableClass,
   NumberOnly,
+  ObjectThatReferencesObjectsWithDuplicateInlineEnums,
   ObjectWithDeprecatedFields,
+  ObjectWithDuplicateInlineEnum,
+  ObjectWithInlineEnum,
   Order,
   OuterComposite,
   OuterEnum,

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/object_that_references_objects_with_duplicate_inline_enums_test.dart

@@ -0,0 +1,21 @@
+import 'package:test/test.dart';
+import 'package:openapi/openapi.dart';
+
+// tests for ObjectThatReferencesObjectsWithDuplicateInlineEnums
+void main() {
+  final instance = ObjectThatReferencesObjectsWithDuplicateInlineEnumsBuilder();
+  // TODO add properties to the builder and call build()
+
+  group(ObjectThatReferencesObjectsWithDuplicateInlineEnums, () {
+    // ObjectWithInlineEnum objectOne
+    test('to test the property `objectOne`', () async {
+      // TODO
+    });
+
+    // ObjectWithDuplicateInlineEnum objectTwo
+    test('to test the property `objectTwo`', () async {
+      // TODO
+    });
+
+  });
+}

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/object_with_duplicate_inline_enum_test.dart

@@ -0,0 +1,17 @@
+import 'package:test/test.dart';
+import 'package:openapi/openapi.dart';
+
+// tests for ObjectWithDuplicateInlineEnum
+void main() {
+  final instance = ObjectWithDuplicateInlineEnumBuilder();
+  // TODO add properties to the builder and call build()
+
+  group(ObjectWithDuplicateInlineEnum, () {
+    // Object two attribute enum
+    // BuiltSet<String> attribute
+    test('to test the property `attribute`', () async {
+      // TODO
+    });
+
+  });
+}

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/object_with_inline_enum_test.dart

@@ -0,0 +1,17 @@
+import 'package:test/test.dart';
+import 'package:openapi/openapi.dart';
+
+// tests for ObjectWithInlineEnum
+void main() {
+  final instance = ObjectWithInlineEnumBuilder();
+  // TODO add properties to the builder and call build()
+
+  group(ObjectWithInlineEnum, () {
+    // Object one attribute enum
+    // BuiltSet<String> attribute
+    test('to test the property `attribute`', () async {
+      // TODO
+    });
+
+  });
+}

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/.openapi-generator/FILES

@@ -40,7 +40,10 @@ doc/ModelReturn.md
 doc/Name.md
 doc/NullableClass.md
 doc/NumberOnly.md
+doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md
 doc/ObjectWithDeprecatedFields.md
+doc/ObjectWithDuplicateInlineEnum.md
+doc/ObjectWithInlineEnum.md
 doc/Order.md
 doc/OuterComposite.md
 doc/OuterEnum.md
@@ -112,7 +115,10 @@ lib/model/model_return.dart
 lib/model/name.dart
 lib/model/nullable_class.dart
 lib/model/number_only.dart
+lib/model/object_that_references_objects_with_duplicate_inline_enums.dart
 lib/model/object_with_deprecated_fields.dart
+lib/model/object_with_duplicate_inline_enum.dart
+lib/model/object_with_inline_enum.dart
 lib/model/order.dart
 lib/model/outer_composite.dart
 lib/model/outer_enum.dart

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/README.md

@@ -62,6 +62,7 @@ Class | Method | HTTP request | Description
 *AnotherFakeApi* | [**call123testSpecialTags**](doc//AnotherFakeApi.md#call123testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
 *DefaultApi* | [**fooGet**](doc//DefaultApi.md#fooget) | **GET** /foo | 
 *FakeApi* | [**fakeBigDecimalMap**](doc//FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+*FakeApi* | [**fakeDuplicateInlineEnum**](doc//FakeApi.md#fakeduplicateinlineenum) | **GET** /fake/duplicate-inline-enums | test objects with duplicate inline enums see issue# 21582
 *FakeApi* | [**fakeHealthGet**](doc//FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 *FakeApi* | [**fakeHttpSignatureTest**](doc//FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 *FakeApi* | [**fakeOuterBooleanSerialize**](doc//FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
@@ -143,7 +144,10 @@ Class | Method | HTTP request | Description
  - [Name](doc//Name.md)
  - [NullableClass](doc//NullableClass.md)
  - [NumberOnly](doc//NumberOnly.md)
+ - [ObjectThatReferencesObjectsWithDuplicateInlineEnums](doc//ObjectThatReferencesObjectsWithDuplicateInlineEnums.md)
  - [ObjectWithDeprecatedFields](doc//ObjectWithDeprecatedFields.md)
+ - [ObjectWithDuplicateInlineEnum](doc//ObjectWithDuplicateInlineEnum.md)
+ - [ObjectWithInlineEnum](doc//ObjectWithInlineEnum.md)
  - [Order](doc//Order.md)
  - [OuterComposite](doc//OuterComposite.md)
  - [OuterEnum](doc//OuterEnum.md)

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/doc/FakeApi.md

@@ -10,6 +10,7 @@ All URIs are relative to *http://petstore.swagger.io:80/v2*
 Method | HTTP request | Description
 ------------- | ------------- | -------------
 [**fakeBigDecimalMap**](FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+[**fakeDuplicateInlineEnum**](FakeApi.md#fakeduplicateinlineenum) | **GET** /fake/duplicate-inline-enums | test objects with duplicate inline enums see issue# 21582
 [**fakeHealthGet**](FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 [**fakeHttpSignatureTest**](FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 [**fakeOuterBooleanSerialize**](FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
@@ -72,6 +73,43 @@ No authorization required
 
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
+# **fakeDuplicateInlineEnum**
+> ObjectThatReferencesObjectsWithDuplicateInlineEnums fakeDuplicateInlineEnum()
+
+test objects with duplicate inline enums see issue# 21582
+
+### Example
+```dart
+import 'package:openapi/api.dart';
+
+final api_instance = FakeApi();
+
+try {
+    final result = api_instance.fakeDuplicateInlineEnum();
+    print(result);
+} catch (e) {
+    print('Exception when calling FakeApi->fakeDuplicateInlineEnum: $e\n');
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+[**ObjectThatReferencesObjectsWithDuplicateInlineEnums**](ObjectThatReferencesObjectsWithDuplicateInlineEnums.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
 # **fakeHealthGet**
 > HealthCheckResult fakeHealthGet()
 

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/doc/ObjectThatReferencesObjectsWithDuplicateInlineEnums.md

@@ -0,0 +1,16 @@
+# openapi.model.ObjectThatReferencesObjectsWithDuplicateInlineEnums
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**objectOne** | [**ObjectWithInlineEnum**](ObjectWithInlineEnum.md) |  | [optional] 
+**objectTwo** | [**ObjectWithDuplicateInlineEnum**](ObjectWithDuplicateInlineEnum.md) |  | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/doc/ObjectWithDuplicateInlineEnum.md

@@ -0,0 +1,15 @@
+# openapi.model.ObjectWithDuplicateInlineEnum
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**attribute** | **Set<String>** | Object two attribute enum | [optional] [default to const {}]
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/doc/ObjectWithInlineEnum.md

@@ -0,0 +1,15 @@
+# openapi.model.ObjectWithInlineEnum
+
+## Load the model package
+```dart
+import 'package:openapi/api.dart';
+```
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**attribute** | **Set<String>** | Object one attribute enum | [optional] [default to const {}]
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api.dart

@@ -70,7 +70,10 @@ part 'model/model_return.dart';
 part 'model/name.dart';
 part 'model/nullable_class.dart';
 part 'model/number_only.dart';
+part 'model/object_that_references_objects_with_duplicate_inline_enums.dart';
 part 'model/object_with_deprecated_fields.dart';
+part 'model/object_with_duplicate_inline_enum.dart';
+part 'model/object_with_inline_enum.dart';
 part 'model/order.dart';
 part 'model/outer_composite.dart';
 part 'model/outer_enum.dart';

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api/fake_api.dart

@@ -60,6 +60,50 @@ class FakeApi {
     return null;
   }
 
+  /// test objects with duplicate inline enums see issue# 21582
+  ///
+  /// Note: This method returns the HTTP [Response].
+  Future<Response> fakeDuplicateInlineEnumWithHttpInfo() async {
+    // ignore: prefer_const_declarations
+    final path = r'/fake/duplicate-inline-enums';
+
+    // ignore: prefer_final_locals
+    Object? postBody;
+
+    final queryParams = <QueryParam>[];
+    final headerParams = <String, String>{};
+    final formParams = <String, String>{};
+
+    const contentTypes = <String>[];
+
+
+    return apiClient.invokeAPI(
+      path,
+      'GET',
+      queryParams,
+      postBody,
+      headerParams,
+      formParams,
+      contentTypes.isEmpty ? null : contentTypes.first,
+    );
+  }
+
+  /// test objects with duplicate inline enums see issue# 21582
+  Future<ObjectThatReferencesObjectsWithDuplicateInlineEnums?> fakeDuplicateInlineEnum() async {
+    final response = await fakeDuplicateInlineEnumWithHttpInfo();
+    if (response.statusCode >= HttpStatus.badRequest) {
+      throw ApiException(response.statusCode, await _decodeBodyBytes(response));
+    }
+    // When a remote server returns no body with a status of 204, we shall not decode it.
+    // At the time of writing this, `dart:convert` will throw an "Unexpected end of input"
+    // FormatException when trying to decode an empty string.
+    if (response.body.isNotEmpty && response.statusCode != HttpStatus.noContent) {
+      return await apiClient.deserializeAsync(await _decodeBodyBytes(response), 'ObjectThatReferencesObjectsWithDuplicateInlineEnums',) as ObjectThatReferencesObjectsWithDuplicateInlineEnums;
+    
+    }
+    return null;
+  }
+
   /// Health check endpoint
   ///
   /// Note: This method returns the HTTP [Response].

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api_client.dart

@@ -250,8 +250,14 @@ class ApiClient {
           return NullableClass.fromJson(value);
         case 'NumberOnly':
           return NumberOnly.fromJson(value);
+        case 'ObjectThatReferencesObjectsWithDuplicateInlineEnums':
+          return ObjectThatReferencesObjectsWithDuplicateInlineEnums.fromJson(value);
         case 'ObjectWithDeprecatedFields':
           return ObjectWithDeprecatedFields.fromJson(value);
+        case 'ObjectWithDuplicateInlineEnum':
+          return ObjectWithDuplicateInlineEnum.fromJson(value);
+        case 'ObjectWithInlineEnum':
+          return ObjectWithInlineEnum.fromJson(value);
         case 'Order':
           return Order.fromJson(value);
         case 'OuterComposite':

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_that_references_objects_with_duplicate_inline_enums.dart

@@ -0,0 +1,135 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.18
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+part of openapi.api;
+
+class ObjectThatReferencesObjectsWithDuplicateInlineEnums {
+  /// Returns a new [ObjectThatReferencesObjectsWithDuplicateInlineEnums] instance.
+  ObjectThatReferencesObjectsWithDuplicateInlineEnums({
+    this.objectOne,
+    this.objectTwo,
+  });
+
+  ///
+  /// Please note: This property should have been non-nullable! Since the specification file
+  /// does not include a default value (using the "default:" property), however, the generated
+  /// source code must fall back to having a nullable type.
+  /// Consider adding a "default:" property in the specification file to hide this note.
+  ///
+  ObjectWithInlineEnum? objectOne;
+
+  ///
+  /// Please note: This property should have been non-nullable! Since the specification file
+  /// does not include a default value (using the "default:" property), however, the generated
+  /// source code must fall back to having a nullable type.
+  /// Consider adding a "default:" property in the specification file to hide this note.
+  ///
+  ObjectWithDuplicateInlineEnum? objectTwo;
+
+  @override
+  bool operator ==(Object other) => identical(this, other) || other is ObjectThatReferencesObjectsWithDuplicateInlineEnums &&
+    other.objectOne == objectOne &&
+    other.objectTwo == objectTwo;
+
+  @override
+  int get hashCode =>
+    // ignore: unnecessary_parenthesis
+    (objectOne == null ? 0 : objectOne!.hashCode) +
+    (objectTwo == null ? 0 : objectTwo!.hashCode);
+
+  @override
+  String toString() => 'ObjectThatReferencesObjectsWithDuplicateInlineEnums[objectOne=$objectOne, objectTwo=$objectTwo]';
+
+  Map<String, dynamic> toJson() {
+    final json = <String, dynamic>{};
+    if (this.objectOne != null) {
+      json[r'object_one'] = this.objectOne;
+    } else {
+      json[r'object_one'] = null;
+    }
+    if (this.objectTwo != null) {
+      json[r'object_two'] = this.objectTwo;
+    } else {
+      json[r'object_two'] = null;
+    }
+    return json;
+  }
+
+  /// Returns a new [ObjectThatReferencesObjectsWithDuplicateInlineEnums] instance and imports its values from
+  /// [value] if it's a [Map], null otherwise.
+  // ignore: prefer_constructors_over_static_methods
+  static ObjectThatReferencesObjectsWithDuplicateInlineEnums? fromJson(dynamic value) {
+    if (value is Map) {
+      final json = value.cast<String, dynamic>();
+
+      // Ensure that the map contains the required keys.
+      // Note 1: the values aren't checked for validity beyond being non-null.
+      // Note 2: this code is stripped in release mode!
+      assert(() {
+        requiredKeys.forEach((key) {
+          assert(json.containsKey(key), 'Required key "ObjectThatReferencesObjectsWithDuplicateInlineEnums[$key]" is missing from JSON.');
+          assert(json[key] != null, 'Required key "ObjectThatReferencesObjectsWithDuplicateInlineEnums[$key]" has a null value in JSON.');
+        });
+        return true;
+      }());
+
+      return ObjectThatReferencesObjectsWithDuplicateInlineEnums(
+        objectOne: ObjectWithInlineEnum.fromJson(json[r'object_one']),
+        objectTwo: ObjectWithDuplicateInlineEnum.fromJson(json[r'object_two']),
+      );
+    }
+    return null;
+  }
+
+  static List<ObjectThatReferencesObjectsWithDuplicateInlineEnums> listFromJson(dynamic json, {bool growable = false,}) {
+    final result = <ObjectThatReferencesObjectsWithDuplicateInlineEnums>[];
+    if (json is List && json.isNotEmpty) {
+      for (final row in json) {
+        final value = ObjectThatReferencesObjectsWithDuplicateInlineEnums.fromJson(row);
+        if (value != null) {
+          result.add(value);
+        }
+      }
+    }
+    return result.toList(growable: growable);
+  }
+
+  static Map<String, ObjectThatReferencesObjectsWithDuplicateInlineEnums> mapFromJson(dynamic json) {
+    final map = <String, ObjectThatReferencesObjectsWithDuplicateInlineEnums>{};
+    if (json is Map && json.isNotEmpty) {
+      json = json.cast<String, dynamic>(); // ignore: parameter_assignments
+      for (final entry in json.entries) {
+        final value = ObjectThatReferencesObjectsWithDuplicateInlineEnums.fromJson(entry.value);
+        if (value != null) {
+          map[entry.key] = value;
+        }
+      }
+    }
+    return map;
+  }
+
+  // maps a json object with a list of ObjectThatReferencesObjectsWithDuplicateInlineEnums-objects as value to a dart map
+  static Map<String, List<ObjectThatReferencesObjectsWithDuplicateInlineEnums>> mapListFromJson(dynamic json, {bool growable = false,}) {
+    final map = <String, List<ObjectThatReferencesObjectsWithDuplicateInlineEnums>>{};
+    if (json is Map && json.isNotEmpty) {
+      // ignore: parameter_assignments
+      json = json.cast<String, dynamic>();
+      for (final entry in json.entries) {
+        map[entry.key] = ObjectThatReferencesObjectsWithDuplicateInlineEnums.listFromJson(entry.value, growable: growable,);
+      }
+    }
+    return map;
+  }
+
+  /// The list of required keys that must be present in a JSON.
+  static const requiredKeys = <String>{
+  };
+}
+

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_with_duplicate_inline_enum.dart

@@ -0,0 +1,183 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.18
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+part of openapi.api;
+
+class ObjectWithDuplicateInlineEnum {
+  /// Returns a new [ObjectWithDuplicateInlineEnum] instance.
+  ObjectWithDuplicateInlineEnum({
+    this.attribute = const {},
+  });
+
+  /// Object two attribute enum
+  Set<ObjectWithDuplicateInlineEnumAttributeEnum> attribute;
+
+  @override
+  bool operator ==(Object other) => identical(this, other) || other is ObjectWithDuplicateInlineEnum &&
+    _deepEquality.equals(other.attribute, attribute);
+
+  @override
+  int get hashCode =>
+    // ignore: unnecessary_parenthesis
+    (attribute.hashCode);
+
+  @override
+  String toString() => 'ObjectWithDuplicateInlineEnum[attribute=$attribute]';
+
+  Map<String, dynamic> toJson() {
+    final json = <String, dynamic>{};
+      json[r'attribute'] = this.attribute.toList(growable: false);
+    return json;
+  }
+
+  /// Returns a new [ObjectWithDuplicateInlineEnum] instance and imports its values from
+  /// [value] if it's a [Map], null otherwise.
+  // ignore: prefer_constructors_over_static_methods
+  static ObjectWithDuplicateInlineEnum? fromJson(dynamic value) {
+    if (value is Map) {
+      final json = value.cast<String, dynamic>();
+
+      // Ensure that the map contains the required keys.
+      // Note 1: the values aren't checked for validity beyond being non-null.
+      // Note 2: this code is stripped in release mode!
+      assert(() {
+        requiredKeys.forEach((key) {
+          assert(json.containsKey(key), 'Required key "ObjectWithDuplicateInlineEnum[$key]" is missing from JSON.');
+          assert(json[key] != null, 'Required key "ObjectWithDuplicateInlineEnum[$key]" has a null value in JSON.');
+        });
+        return true;
+      }());
+
+      return ObjectWithDuplicateInlineEnum(
+        attribute: ObjectWithDuplicateInlineEnumAttributeEnum.listFromJson(json[r'attribute']).toSet(),
+      );
+    }
+    return null;
+  }
+
+  static List<ObjectWithDuplicateInlineEnum> listFromJson(dynamic json, {bool growable = false,}) {
+    final result = <ObjectWithDuplicateInlineEnum>[];
+    if (json is List && json.isNotEmpty) {
+      for (final row in json) {
+        final value = ObjectWithDuplicateInlineEnum.fromJson(row);
+        if (value != null) {
+          result.add(value);
+        }
+      }
+    }
+    return result.toList(growable: growable);
+  }
+
+  static Map<String, ObjectWithDuplicateInlineEnum> mapFromJson(dynamic json) {
+    final map = <String, ObjectWithDuplicateInlineEnum>{};
+    if (json is Map && json.isNotEmpty) {
+      json = json.cast<String, dynamic>(); // ignore: parameter_assignments
+      for (final entry in json.entries) {
+        final value = ObjectWithDuplicateInlineEnum.fromJson(entry.value);
+        if (value != null) {
+          map[entry.key] = value;
+        }
+      }
+    }
+    return map;
+  }
+
+  // maps a json object with a list of ObjectWithDuplicateInlineEnum-objects as value to a dart map
+  static Map<String, List<ObjectWithDuplicateInlineEnum>> mapListFromJson(dynamic json, {bool growable = false,}) {
+    final map = <String, List<ObjectWithDuplicateInlineEnum>>{};
+    if (json is Map && json.isNotEmpty) {
+      // ignore: parameter_assignments
+      json = json.cast<String, dynamic>();
+      for (final entry in json.entries) {
+        map[entry.key] = ObjectWithDuplicateInlineEnum.listFromJson(entry.value, growable: growable,);
+      }
+    }
+    return map;
+  }
+
+  /// The list of required keys that must be present in a JSON.
+  static const requiredKeys = <String>{
+  };
+}
+
+
+class ObjectWithDuplicateInlineEnumAttributeEnum {
+  /// Instantiate a new enum with the provided [value].
+  const ObjectWithDuplicateInlineEnumAttributeEnum._(this.value);
+
+  /// The underlying value of this enum member.
+  final String value;
+
+  @override
+  String toString() => value;
+
+  String toJson() => value;
+
+  static const valueOne = ObjectWithDuplicateInlineEnumAttributeEnum._(r'value_one');
+  static const valueTwo = ObjectWithDuplicateInlineEnumAttributeEnum._(r'value_two');
+
+  /// List of all possible values in this [enum][ObjectWithDuplicateInlineEnumAttributeEnum].
+  static const values = <ObjectWithDuplicateInlineEnumAttributeEnum>[
+    valueOne,
+    valueTwo,
+  ];
+
+  static ObjectWithDuplicateInlineEnumAttributeEnum? fromJson(dynamic value) => ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer().decode(value);
+
+  static List<ObjectWithDuplicateInlineEnumAttributeEnum> listFromJson(dynamic json, {bool growable = false,}) {
+    final result = <ObjectWithDuplicateInlineEnumAttributeEnum>[];
+    if (json is List && json.isNotEmpty) {
+      for (final row in json) {
+        final value = ObjectWithDuplicateInlineEnumAttributeEnum.fromJson(row);
+        if (value != null) {
+          result.add(value);
+        }
+      }
+    }
+    return result.toList(growable: growable);
+  }
+}
+
+/// Transformation class that can [encode] an instance of [ObjectWithDuplicateInlineEnumAttributeEnum] to String,
+/// and [decode] dynamic data back to [ObjectWithDuplicateInlineEnumAttributeEnum].
+class ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer {
+  factory ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer() => _instance ??= const ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer._();
+
+  const ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer._();
+
+  String encode(ObjectWithDuplicateInlineEnumAttributeEnum data) => data.value;
+
+  /// Decodes a [dynamic value][data] to a ObjectWithDuplicateInlineEnumAttributeEnum.
+  ///
+  /// If [allowNull] is true and the [dynamic value][data] cannot be decoded successfully,
+  /// then null is returned. However, if [allowNull] is false and the [dynamic value][data]
+  /// cannot be decoded successfully, then an [UnimplementedError] is thrown.
+  ///
+  /// The [allowNull] is very handy when an API changes and a new enum value is added or removed,
+  /// and users are still using an old app with the old code.
+  ObjectWithDuplicateInlineEnumAttributeEnum? decode(dynamic data, {bool allowNull = true}) {
+    if (data != null) {
+      switch (data) {
+        case r'value_one': return ObjectWithDuplicateInlineEnumAttributeEnum.valueOne;
+        case r'value_two': return ObjectWithDuplicateInlineEnumAttributeEnum.valueTwo;
+        default:
+          if (!allowNull) {
+            throw ArgumentError('Unknown enum value to decode: $data');
+          }
+      }
+    }
+    return null;
+  }
+
+  /// Singleton [ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer] instance.
+  static ObjectWithDuplicateInlineEnumAttributeEnumTypeTransformer? _instance;
+}
+
+

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/object_with_inline_enum.dart

@@ -0,0 +1,183 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.18
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+part of openapi.api;
+
+class ObjectWithInlineEnum {
+  /// Returns a new [ObjectWithInlineEnum] instance.
+  ObjectWithInlineEnum({
+    this.attribute = const {},
+  });
+
+  /// Object one attribute enum
+  Set<ObjectWithInlineEnumAttributeEnum> attribute;
+
+  @override
+  bool operator ==(Object other) => identical(this, other) || other is ObjectWithInlineEnum &&
+    _deepEquality.equals(other.attribute, attribute);
+
+  @override
+  int get hashCode =>
+    // ignore: unnecessary_parenthesis
+    (attribute.hashCode);
+
+  @override
+  String toString() => 'ObjectWithInlineEnum[attribute=$attribute]';
+
+  Map<String, dynamic> toJson() {
+    final json = <String, dynamic>{};
+      json[r'attribute'] = this.attribute.toList(growable: false);
+    return json;
+  }
+
+  /// Returns a new [ObjectWithInlineEnum] instance and imports its values from
+  /// [value] if it's a [Map], null otherwise.
+  // ignore: prefer_constructors_over_static_methods
+  static ObjectWithInlineEnum? fromJson(dynamic value) {
+    if (value is Map) {
+      final json = value.cast<String, dynamic>();
+
+      // Ensure that the map contains the required keys.
+      // Note 1: the values aren't checked for validity beyond being non-null.
+      // Note 2: this code is stripped in release mode!
+      assert(() {
+        requiredKeys.forEach((key) {
+          assert(json.containsKey(key), 'Required key "ObjectWithInlineEnum[$key]" is missing from JSON.');
+          assert(json[key] != null, 'Required key "ObjectWithInlineEnum[$key]" has a null value in JSON.');
+        });
+        return true;
+      }());
+
+      return ObjectWithInlineEnum(
+        attribute: ObjectWithInlineEnumAttributeEnum.listFromJson(json[r'attribute']).toSet(),
+      );
+    }
+    return null;
+  }
+
+  static List<ObjectWithInlineEnum> listFromJson(dynamic json, {bool growable = false,}) {
+    final result = <ObjectWithInlineEnum>[];
+    if (json is List && json.isNotEmpty) {
+      for (final row in json) {
+        final value = ObjectWithInlineEnum.fromJson(row);
+        if (value != null) {
+          result.add(value);
+        }
+      }
+    }
+    return result.toList(growable: growable);
+  }
+
+  static Map<String, ObjectWithInlineEnum> mapFromJson(dynamic json) {
+    final map = <String, ObjectWithInlineEnum>{};
+    if (json is Map && json.isNotEmpty) {
+      json = json.cast<String, dynamic>(); // ignore: parameter_assignments
+      for (final entry in json.entries) {
+        final value = ObjectWithInlineEnum.fromJson(entry.value);
+        if (value != null) {
+          map[entry.key] = value;
+        }
+      }
+    }
+    return map;
+  }
+
+  // maps a json object with a list of ObjectWithInlineEnum-objects as value to a dart map
+  static Map<String, List<ObjectWithInlineEnum>> mapListFromJson(dynamic json, {bool growable = false,}) {
+    final map = <String, List<ObjectWithInlineEnum>>{};
+    if (json is Map && json.isNotEmpty) {
+      // ignore: parameter_assignments
+      json = json.cast<String, dynamic>();
+      for (final entry in json.entries) {
+        map[entry.key] = ObjectWithInlineEnum.listFromJson(entry.value, growable: growable,);
+      }
+    }
+    return map;
+  }
+
+  /// The list of required keys that must be present in a JSON.
+  static const requiredKeys = <String>{
+  };
+}
+
+
+class ObjectWithInlineEnumAttributeEnum {
+  /// Instantiate a new enum with the provided [value].
+  const ObjectWithInlineEnumAttributeEnum._(this.value);
+
+  /// The underlying value of this enum member.
+  final String value;
+
+  @override
+  String toString() => value;
+
+  String toJson() => value;
+
+  static const valueOne = ObjectWithInlineEnumAttributeEnum._(r'value_one');
+  static const valueTwo = ObjectWithInlineEnumAttributeEnum._(r'value_two');
+
+  /// List of all possible values in this [enum][ObjectWithInlineEnumAttributeEnum].
+  static const values = <ObjectWithInlineEnumAttributeEnum>[
+    valueOne,
+    valueTwo,
+  ];
+
+  static ObjectWithInlineEnumAttributeEnum? fromJson(dynamic value) => ObjectWithInlineEnumAttributeEnumTypeTransformer().decode(value);
+
+  static List<ObjectWithInlineEnumAttributeEnum> listFromJson(dynamic json, {bool growable = false,}) {
+    final result = <ObjectWithInlineEnumAttributeEnum>[];
+    if (json is List && json.isNotEmpty) {
+      for (final row in json) {
+        final value = ObjectWithInlineEnumAttributeEnum.fromJson(row);
+        if (value != null) {
+          result.add(value);
+        }
+      }
+    }
+    return result.toList(growable: growable);
+  }
+}
+
+/// Transformation class that can [encode] an instance of [ObjectWithInlineEnumAttributeEnum] to String,
+/// and [decode] dynamic data back to [ObjectWithInlineEnumAttributeEnum].
+class ObjectWithInlineEnumAttributeEnumTypeTransformer {
+  factory ObjectWithInlineEnumAttributeEnumTypeTransformer() => _instance ??= const ObjectWithInlineEnumAttributeEnumTypeTransformer._();
+
+  const ObjectWithInlineEnumAttributeEnumTypeTransformer._();
+
+  String encode(ObjectWithInlineEnumAttributeEnum data) => data.value;
+
+  /// Decodes a [dynamic value][data] to a ObjectWithInlineEnumAttributeEnum.
+  ///
+  /// If [allowNull] is true and the [dynamic value][data] cannot be decoded successfully,
+  /// then null is returned. However, if [allowNull] is false and the [dynamic value][data]
+  /// cannot be decoded successfully, then an [UnimplementedError] is thrown.
+  ///
+  /// The [allowNull] is very handy when an API changes and a new enum value is added or removed,
+  /// and users are still using an old app with the old code.
+  ObjectWithInlineEnumAttributeEnum? decode(dynamic data, {bool allowNull = true}) {
+    if (data != null) {
+      switch (data) {
+        case r'value_one': return ObjectWithInlineEnumAttributeEnum.valueOne;
+        case r'value_two': return ObjectWithInlineEnumAttributeEnum.valueTwo;
+        default:
+          if (!allowNull) {
+            throw ArgumentError('Unknown enum value to decode: $data');
+          }
+      }
+    }
+    return null;
+  }
+
+  /// Singleton [ObjectWithInlineEnumAttributeEnumTypeTransformer] instance.
+  static ObjectWithInlineEnumAttributeEnumTypeTransformer? _instance;
+}
+
+

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/test/object_that_references_objects_with_duplicate_inline_enums_test.dart

@@ -0,0 +1,32 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.18
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for ObjectThatReferencesObjectsWithDuplicateInlineEnums
+void main() {
+  // final instance = ObjectThatReferencesObjectsWithDuplicateInlineEnums();
+
+  group('test ObjectThatReferencesObjectsWithDuplicateInlineEnums', () {
+    // ObjectWithInlineEnum objectOne
+    test('to test the property `objectOne`', () async {
+      // TODO
+    });
+
+    // ObjectWithDuplicateInlineEnum objectTwo
+    test('to test the property `objectTwo`', () async {
+      // TODO
+    });
+
+
+  });
+
+}

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/test/object_with_duplicate_inline_enum_test.dart

@@ -0,0 +1,28 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.18
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for ObjectWithDuplicateInlineEnum
+void main() {
+  // final instance = ObjectWithDuplicateInlineEnum();
+
+  group('test ObjectWithDuplicateInlineEnum', () {
+    // Object two attribute enum
+    // Set<String> attribute (default value: const {})
+    test('to test the property `attribute`', () async {
+      // TODO
+    });
+
+
+  });
+
+}

samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/test/object_with_inline_enum_test.dart

@@ -0,0 +1,28 @@
+//
+// AUTO-GENERATED FILE, DO NOT MODIFY!
+//
+// @dart=2.18
+
+// ignore_for_file: unused_element, unused_import
+// ignore_for_file: always_put_required_named_parameters_first
+// ignore_for_file: constant_identifier_names
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:openapi/api.dart';
+import 'package:test/test.dart';
+
+// tests for ObjectWithInlineEnum
+void main() {
+  // final instance = ObjectWithInlineEnum();
+
+  group('test ObjectWithInlineEnum', () {
+    // Object one attribute enum
+    // Set<String> attribute (default value: const {})
+    test('to test the property `attribute`', () async {
+      // TODO
+    });
+
+
+  });
+
+}