[BUG] fix(InlineModelResolver): do not merge distinct inline enums sharing the same values (#23978)

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

@@ -849,6 +849,10 @@ private String resolveModelName(String title, String modelName) {
         }
     }
 
+    private static boolean isEnumSchema(Schema model) {
+        return model != null && model.getEnum() != null && !model.getEnum().isEmpty();
+    }
+
     private String matchGenerated(Schema model) {
         if (skipSchemaReuse) { // skip reusing schema
             return null;
@@ -862,9 +866,18 @@ private String matchGenerated(Schema model) {
             }
             // Structural match: compare with volatile fields stripped at every level.
             // See generatedStructuralSignature field for a full explanation of why this is needed.
-            String structural = computeStructuralSignature(model);
-            if (generatedStructuralSignature.containsKey(structural)) {
-                return generatedStructuralSignature.get(structural);
+            //
+            // Skip this fallback for enum schemas: the structural matcher strips 'description',
+            // but for an enum the description is the only thing distinguishing two schemas that
+            // share the same values yet represent different things (e.g. two properties whose
+            // enums happen to list the same values but mean different things). Stripping it would
+            // wrongly unify them and make the second usage silently reuse the first enum's type
+            // (#23978). Enum schemas therefore dedup on exact content only.
+            if (!isEnumSchema(model)) {
+                String structural = computeStructuralSignature(model);
+                if (generatedStructuralSignature.containsKey(structural)) {
+                    return generatedStructuralSignature.get(structural);
+                }
             }
         } catch (JsonProcessingException e) {
             e.printStackTrace();

modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java

@@ -1385,6 +1385,45 @@ public void resolveInlineModelDeduplicatesWhenParserMutatesPropertyTypes() {
                 schemas.get("StorageBackend_1"));
     }
 
+    @Test
+    public void doNotMergeDistinctInlineEnumsSharingTheSameValues() {
+        // Regression test for #23978: two inline enum properties that share the same enum values
+        // but represent different things (distinguished only by their description) must each be
+        // promoted to their own schema.  The structural-signature fallback in matchGenerated()
+        // strips 'description', so without an enum guard it would wrongly unify them and the
+        // second property would silently reuse the first enum's type (regression in 7.23.0).
+        OpenAPI openapi = new OpenAPI();
+        openapi.setComponents(new Components());
+        openapi.setPaths(new Paths());
+
+        StringSchema statusEnum = new StringSchema();
+        statusEnum.setDescription("Lifecycle status of the order");
+        statusEnum.setEnum(java.util.Arrays.asList("ACTIVE", "INACTIVE"));
+
+        StringSchema visibilityEnum = new StringSchema();
+        visibilityEnum.setDescription("Whether the order is visible to the customer");
+        visibilityEnum.setEnum(java.util.Arrays.asList("ACTIVE", "INACTIVE"));
+
+        openapi.getComponents().addSchemas("Order", new ObjectSchema()
+                .title("Order")
+                .addProperty("status", statusEnum)
+                .addProperty("visibility", visibilityEnum));
+
+        InlineModelResolver resolver = new InlineModelResolver();
+        Map<String, String> options = new HashMap<>();
+        options.put("RESOLVE_INLINE_ENUMS", "true");
+        resolver.setInlineSchemaOptions(options);
+        resolver.flatten(openapi);
+
+        Schema order = openapi.getComponents().getSchemas().get("Order");
+        String statusRef = ((Schema) order.getProperties().get("status")).get$ref();
+        String visibilityRef = ((Schema) order.getProperties().get("visibility")).get$ref();
+        assertNotNull("status enum must be promoted to its own schema", statusRef);
+        assertNotNull("visibility enum must be promoted to its own schema", visibilityRef);
+        assertFalse("Distinct inline enums sharing the same values must not be merged (#23978)",
+                statusRef.equals(visibilityRef));
+    }
+
     @Test
     public void deduplicateComponentsRemovesNumberedDuplicateOfTitledSchemaAndRewritesRefs() {
         // Regression test: when flattening creates a numbered duplicate of a titled component

samples/client/petstore/csharp/generichost/net10/FormModels/.openapi-generator/FILES

@@ -121,6 +121,7 @@ docs/models/TestCollectionEndingWithWordList.md
 docs/models/TestCollectionEndingWithWordListObject.md
 docs/models/TestDescendants.md
 docs/models/TestDescendantsObjectType.md
+docs/models/TestEnumParametersEnumHeaderStringParameter.md
 docs/models/TestEnumParametersEnumQueryDoubleParameter.md
 docs/models/TestEnumParametersEnumQueryIntegerParameter.md
 docs/models/TestEnumParametersRequestEnumFormString.md
@@ -289,6 +290,7 @@ src/Org.OpenAPITools/Model/TestCollectionEndingWithWordList.cs
 src/Org.OpenAPITools/Model/TestCollectionEndingWithWordListObject.cs
 src/Org.OpenAPITools/Model/TestDescendants.cs
 src/Org.OpenAPITools/Model/TestDescendantsObjectType.cs
+src/Org.OpenAPITools/Model/TestEnumParametersEnumHeaderStringParameter.cs
 src/Org.OpenAPITools/Model/TestEnumParametersEnumQueryDoubleParameter.cs
 src/Org.OpenAPITools/Model/TestEnumParametersEnumQueryIntegerParameter.cs
 src/Org.OpenAPITools/Model/TestEnumParametersRequestEnumFormString.cs

samples/client/petstore/csharp/generichost/net10/FormModels/api/openapi.yaml

@@ -772,7 +772,7 @@ paths:
         name: enum_header_string
         required: false
         schema:
-          $ref: "#/components/schemas/testEnumParameters_request_enum_form_string"
+          $ref: "#/components/schemas/testEnumParameters_enum_header_string_parameter"
         style: simple
       - description: Query parameter enum test (string array)
         explode: true
@@ -790,7 +790,7 @@ paths:
         name: enum_query_string
         required: false
         schema:
-          $ref: "#/components/schemas/testEnumParameters_request_enum_form_string"
+          $ref: "#/components/schemas/testEnumParameters_enum_header_string_parameter"
         style: form
       - description: Query parameter enum test (double)
         explode: true
@@ -2819,6 +2819,13 @@ components:
         enum_form_string:
           $ref: "#/components/schemas/testEnumParameters_request_enum_form_string"
       type: object
+    testEnumParameters_enum_header_string_parameter:
+      default: -efg
+      enum:
+      - _abc
+      - -efg
+      - (xyz)
+      type: string
     testEnumParameters_enum_query_integer_parameter:
       enum:
       - 1

samples/client/petstore/csharp/generichost/net10/FormModels/docs/apis/FakeApi.md

@@ -483,7 +483,7 @@ void (empty response body)
 
 <a id="testenumparameters"></a>
 # **TestEnumParameters**
-> void TestEnumParameters (TestEnumParametersRequestEnumFormString enumFormString = null, List<TestEnumParametersRequestEnumFormStringArrayInner> enumFormStringArray = null, TestEnumParametersRequestEnumFormString enumHeaderString = null, List<TestEnumParametersRequestEnumFormStringArrayInner> enumHeaderStringArray = null, TestEnumParametersEnumQueryDoubleParameter enumQueryDouble = null, TestEnumParametersEnumQueryIntegerParameter enumQueryInteger = null, TestEnumParametersRequestEnumFormString enumQueryString = null, List<TestEnumParametersRequestEnumFormStringArrayInner> enumQueryStringArray = null)
+> void TestEnumParameters (TestEnumParametersRequestEnumFormString enumFormString = null, List<TestEnumParametersRequestEnumFormStringArrayInner> enumFormStringArray = null, TestEnumParametersEnumHeaderStringParameter enumHeaderString = null, List<TestEnumParametersRequestEnumFormStringArrayInner> enumHeaderStringArray = null, TestEnumParametersEnumQueryDoubleParameter enumQueryDouble = null, TestEnumParametersEnumQueryIntegerParameter enumQueryInteger = null, TestEnumParametersEnumHeaderStringParameter enumQueryString = null, List<TestEnumParametersRequestEnumFormStringArrayInner> enumQueryStringArray = null)
 
 To test enum parameters
 
@@ -496,11 +496,11 @@ To test enum parameters
 |------|------|-------------|-------|
 | **enumFormString** | **TestEnumParametersRequestEnumFormString** |  | [optional]  |
 | **enumFormStringArray** | [**List&lt;TestEnumParametersRequestEnumFormStringArrayInner&gt;**](TestEnumParametersRequestEnumFormStringArrayInner.md) | Form parameter enum test (string array) | [optional]  |
-| **enumHeaderString** | **TestEnumParametersRequestEnumFormString** | Header parameter enum test (string) | [optional]  |
+| **enumHeaderString** | **TestEnumParametersEnumHeaderStringParameter** | Header parameter enum test (string) | [optional]  |
 | **enumHeaderStringArray** | [**List&lt;TestEnumParametersRequestEnumFormStringArrayInner&gt;**](TestEnumParametersRequestEnumFormStringArrayInner.md) | Header parameter enum test (string array) | [optional]  |
 | **enumQueryDouble** | **TestEnumParametersEnumQueryDoubleParameter** | Query parameter enum test (double) | [optional]  |
 | **enumQueryInteger** | **TestEnumParametersEnumQueryIntegerParameter** | Query parameter enum test (double) | [optional]  |
-| **enumQueryString** | **TestEnumParametersRequestEnumFormString** | Query parameter enum test (string) | [optional]  |
+| **enumQueryString** | **TestEnumParametersEnumHeaderStringParameter** | Query parameter enum test (string) | [optional]  |
 | **enumQueryStringArray** | [**List&lt;TestEnumParametersRequestEnumFormStringArrayInner&gt;**](TestEnumParametersRequestEnumFormStringArrayInner.md) | Query parameter enum test (string array) | [optional]  |
 
 ### Return type

samples/client/petstore/csharp/generichost/net10/FormModels/docs/models/TestEnumParametersEnumHeaderStringParameter.md

@@ -0,0 +1,9 @@
+# Org.OpenAPITools.Model.TestEnumParametersEnumHeaderStringParameter
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+
+[[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/client/petstore/csharp/generichost/net10/FormModels/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs

@@ -217,11 +217,11 @@ public async Task TestEnumParametersAsyncTest()
         {
             Client.Option<TestEnumParametersRequestEnumFormString> enumFormString = default;
             Client.Option<List<TestEnumParametersRequestEnumFormStringArrayInner>> enumFormStringArray = default;
-            Client.Option<TestEnumParametersRequestEnumFormString> enumHeaderString = default;
+            Client.Option<TestEnumParametersEnumHeaderStringParameter> enumHeaderString = default;
             Client.Option<List<TestEnumParametersRequestEnumFormStringArrayInner>> enumHeaderStringArray = default;
             Client.Option<TestEnumParametersEnumQueryDoubleParameter> enumQueryDouble = default;
             Client.Option<TestEnumParametersEnumQueryIntegerParameter> enumQueryInteger = default;
-            Client.Option<TestEnumParametersRequestEnumFormString> enumQueryString = default;
+            Client.Option<TestEnumParametersEnumHeaderStringParameter> enumQueryString = default;
             Client.Option<List<TestEnumParametersRequestEnumFormStringArrayInner>> enumQueryStringArray = default;
             await _instance.TestEnumParametersAsync(enumFormString, enumFormStringArray, enumHeaderString, enumHeaderStringArray, enumQueryDouble, enumQueryInteger, enumQueryString, enumQueryStringArray);
         }

samples/client/petstore/csharp/generichost/net10/FormModels/src/Org.OpenAPITools.Test/Model/TestEnumParametersEnumHeaderStringParameterTests.cs

@@ -0,0 +1,56 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * Generated by: https://github.com/openapitools/openapi-generator.git
+ */
+
+
+using Xunit;
+
+using System;
+using System.Linq;
+using System.IO;
+using System.Collections.Generic;
+using Org.OpenAPITools.Model;
+using Org.OpenAPITools.Client;
+using System.Reflection;
+
+namespace Org.OpenAPITools.Test.Model
+{
+    /// <summary>
+    ///  Class for testing TestEnumParametersEnumHeaderStringParameter
+    /// </summary>
+    /// <remarks>
+    /// This file is automatically generated by OpenAPI Generator (https://openapi-generator.tech).
+    /// Please update the test case below to test the model.
+    /// </remarks>
+    public class TestEnumParametersEnumHeaderStringParameterTests : IDisposable
+    {
+        // TODO uncomment below to declare an instance variable for TestEnumParametersEnumHeaderStringParameter
+        //private TestEnumParametersEnumHeaderStringParameter instance;
+
+        public TestEnumParametersEnumHeaderStringParameterTests()
+        {
+            // TODO uncomment below to create an instance of TestEnumParametersEnumHeaderStringParameter
+            //instance = new TestEnumParametersEnumHeaderStringParameter();
+        }
+
+        public void Dispose()
+        {
+            // Cleanup when everything is done.
+        }
+
+        /// <summary>
+        /// Test an instance of TestEnumParametersEnumHeaderStringParameter
+        /// </summary>
+        [Fact]
+        public void TestEnumParametersEnumHeaderStringParameterInstanceTest()
+        {
+            // TODO uncomment below to test "IsType" TestEnumParametersEnumHeaderStringParameter
+            //Assert.IsType<TestEnumParametersEnumHeaderStringParameter>(instance);
+        }
+    }
+}