Use enum type for discriminator

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

@@ -3526,22 +3526,30 @@ protected CodegenDiscriminator createDiscriminator(String schemaName, Schema sch
             return null;
         }
         CodegenDiscriminator discriminator = new CodegenDiscriminator();
-        String discPropName = sourceDiscriminator.getPropertyName();
-        discriminator.setPropertyName(toVarName(discPropName));
+        String discriminatorPropertyName = sourceDiscriminator.getPropertyName();
+        discriminator.setPropertyName(toVarName(discriminatorPropertyName));
         discriminator.setPropertyBaseName(sourceDiscriminator.getPropertyName());
         discriminator.setPropertyGetter(toGetter(discriminator.getPropertyName()));
 
         if (sourceDiscriminator.getExtensions() != null) {
             discriminator.setVendorExtensions(sourceDiscriminator.getExtensions());
         }
 
-        // FIXME: for now, we assume that the discriminator property is String
-        discriminator.setPropertyType(typeMapping.get("string"));
+        // FIXME: there are other ways to define the type of the discriminator property (inline
+        //  for example). Handling those scenarios is too complicated for me, I'm leaving it for
+        //  the future..
+        String propertyType =
+            Optional.ofNullable(schema.getProperties())
+                .map(p -> (Schema<?>) p.get(discriminatorPropertyName))
+                .map(Schema::get$ref)
+                .map(ModelUtils::getSimpleRef)
+                .orElseGet(() -> typeMapping.get("string"));
+        discriminator.setPropertyType(propertyType);
 
         // check to see if the discriminator property is an enum string
         if (schema.getProperties() != null &&
-                schema.getProperties().get(discPropName) instanceof StringSchema) {
-            StringSchema s = (StringSchema) schema.getProperties().get(discPropName);
+                schema.getProperties().get(discriminatorPropertyName) instanceof StringSchema) {
+            StringSchema s = (StringSchema) schema.getProperties().get(discriminatorPropertyName);
             if (s.getEnum() != null && !s.getEnum().isEmpty()) { // it's an enum string
                 discriminator.setIsEnum(true);
             }
@@ -3586,7 +3594,7 @@ protected CodegenDiscriminator createDiscriminator(String schemaName, Schema sch
         }
         // if there are composed oneOf/anyOf schemas, add them to this discriminator
         if (ModelUtils.isComposedSchema(schema) && !this.getLegacyDiscriminatorBehavior()) {
-            List<MappedModel> otherDescendants = getOneOfAnyOfDescendants(schemaName, discPropName, (ComposedSchema) schema, openAPI);
+            List<MappedModel> otherDescendants = getOneOfAnyOfDescendants(schemaName, discriminatorPropertyName, (ComposedSchema) schema, openAPI);
             for (MappedModel otherDescendant : otherDescendants) {
                 if (!uniqueDescendants.contains(otherDescendant)) {
                     uniqueDescendants.add(otherDescendant);

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

@@ -56,6 +56,7 @@
 import java.util.stream.Collectors;
 
 import static junit.framework.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.testng.Assert.*;
 
 public class DefaultCodegenTest {
@@ -1509,6 +1510,12 @@ public void testComposedSchemaOneOfDiscriminatorMap() {
         hs.add(new CodegenDiscriminator.MappedModel(mn, mn));
         Assert.assertEquals(cm.discriminator.getMappedModels(), hs);
 
+        // ref oneOf models with enum property discriminator
+        modelName = "FruitOneOfEnumMappingDisc";
+        sc = openAPI.getComponents().getSchemas().get(modelName);
+        cm = codegen.fromModel(modelName, sc);
+        assertThat(cm.discriminator.getPropertyType()).isEqualTo("FruitTypeEnum");
+
         // ref oneOf models with discriminator in the grandparent schemas of those oneof models
         modelName = "FruitGrandparentDisc";
         sc = openAPI.getComponents().getSchemas().get(modelName);

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

@@ -1538,6 +1538,55 @@ public void testDiscriminatorWithoutMappingIssue14731() throws IOException {
         assertFileContains(Paths.get(outputPath + "/src/main/java/org/openapitools/model/ChildWithoutMappingBDTO.java"), "@JsonTypeName");
     }
 
+    @Test
+    void testOneOfWithEnumDiscriminator() throws IOException {
+        File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
+        output.deleteOnExit();
+        String outputPath = output.getAbsolutePath().replace('\\', '/');
+        OpenAPI openAPI = new OpenAPIParser()
+            .readLocation("src/test/resources/3_0/oneOfDiscriminator.yaml", null, new ParseOptions()).getOpenAPI();
+
+        SpringCodegen codegen = new SpringCodegen();
+        codegen.setOutputDir(output.getAbsolutePath());
+        codegen.additionalProperties().put(CXFServerFeatures.LOAD_TEST_DATA_FROM_FILE, "true");
+        codegen.setUseOneOfInterfaces(true);
+
+        ClientOptInput input = new ClientOptInput();
+        input.openAPI(openAPI);
+        input.config(codegen);
+
+        DefaultGenerator generator = new DefaultGenerator();
+        codegen.setHateoas(true);
+        generator.setGeneratorPropertyDefault(CodegenConstants.MODELS, "true");
+        //generator.setGeneratorPropertyDefault(CodegenConstants.USE_ONEOF_DISCRIMINATOR_LOOKUP, "true");
+        generator.setGeneratorPropertyDefault(CodegenConstants.LEGACY_DISCRIMINATOR_BEHAVIOR, "false");
+
+        codegen.setUseOneOfInterfaces(true);
+        codegen.setLegacyDiscriminatorBehavior(false);
+
+        generator.setGeneratorPropertyDefault(CodegenConstants.MODEL_TESTS, "false");
+        generator.setGeneratorPropertyDefault(CodegenConstants.MODEL_DOCS, "false");
+        generator.setGeneratorPropertyDefault(CodegenConstants.APIS, "true");
+        generator.setGeneratorPropertyDefault(CodegenConstants.SUPPORTING_FILES, "false");
+
+        generator.opts(input).generate();
+
+        assertFileContains(
+            Paths.get(outputPath + "/src/main/java/org/openapitools/model/FruitOneOfEnumMappingDisc.java"),
+            "public FruitTypeEnum getFruitType();"
+        );
+        assertFileContains(
+            Paths.get(outputPath + "/src/main/java/org/openapitools/model/AppleOneOfEnumMappingDisc.java"),
+            "private FruitTypeEnum fruitType;",
+            "public FruitTypeEnum getFruitType() {"
+        );
+        assertFileContains(
+            Paths.get(outputPath + "/src/main/java/org/openapitools/model/BananaOneOfEnumMappingDisc.java"),
+            "private FruitTypeEnum fruitType;",
+            "public FruitTypeEnum getFruitType() {"
+        );
+    }
+
     @Test
     public void testTypeMappings() {
         final SpringCodegen codegen = new SpringCodegen();

modules/openapi-generator/src/test/resources/3_0/oneOfDiscriminator.yaml

@@ -170,6 +170,38 @@ components:
           type: integer
       oneOf:
         - $ref: '#/components/schemas/FruitType'
+    FruitTypeEnum:
+      type: string
+      enum: [APPLE, BANANA]
+    FruitOneOfEnumMappingDisc:
+      type: object
+      properties:
+        fruitType:
+          $ref: "#/components/schemas/FruitTypeEnum"
+      required:
+        - fruitType
+      oneOf:
+        - $ref: '#/components/schemas/AppleOneOfEnumMappingDisc'
+        - $ref: '#/components/schemas/BananaOneOfEnumMappingDisc'
+      discriminator:
+        propertyName: fruitType
+        mapping:
+          APPLE: '#/components/schemas/AppleOneOfEnumMappingDisc'
+          BANANA: '#/components/schemas/BananaOneOfEnumMappingDisc'
+    AppleOneOfEnumMappingDisc:
+      type: object
+      required:
+        - seeds
+      properties:
+        seeds:
+          type: integer
+    BananaOneOfEnumMappingDisc:
+      type: object
+      required:
+        - length
+      properties:
+        length:
+          type: integer
     FruitGrandparentDisc:
       oneOf:
         - $ref: '#/components/schemas/AppleGrandparentDisc'

modules/openapi-generator/src/test/resources/3_0/oneof_polymorphism_and_inheritance.yaml

@@ -177,6 +177,38 @@ components:
           type: string
       allOf:
         - $ref: '#/components/schemas/Pizza'
+    FruitType:
+      type: string
+      enum: [APPLE, BANANA]
+    Fruit:
+      type: object
+      properties:
+        fruitType:
+          $ref: "#/components/schemas/FruitType"
+      required:
+        - fruitType
+      oneOf:
+        - $ref: '#/components/schemas/Apple'
+        - $ref: '#/components/schemas/Banana'
+      discriminator:
+        propertyName: fruitType
+        mapping:
+          APPLE: '#/components/schemas/Apple'
+          BANANA: '#/components/schemas/Banana'
+    Apple:
+      type: object
+      required:
+        - seeds
+      properties:
+        seeds:
+          type: integer
+    Banana:
+      type: object
+      required:
+        - length
+      properties:
+        length:
+          type: integer
 
   requestBodies:
     Foo:

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -1438,16 +1438,16 @@ public async Task<ApiResponse<object>> TestBodyWithFileSchemaAsync(FileSchemaTes
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="query"></param>
         /// <param name="user"></param>
+        /// <param name="query"></param>
         /// <returns></returns>
-        private void ValidateTestBodyWithQueryParams(string query, User user)
+        private void ValidateTestBodyWithQueryParams(User user, string query)
         {
-            if (query == null)
-                throw new ArgumentNullException(nameof(query));
-
             if (user == null)
                 throw new ArgumentNullException(nameof(user));
+
+            if (query == null)
+                throw new ArgumentNullException(nameof(query));
         }
 
         /// <summary>
@@ -1530,7 +1530,7 @@ public async Task<ApiResponse<object>> TestBodyWithQueryParamsAsync(User user, s
 
             try
             {
-                ValidateTestBodyWithQueryParams(query, user);
+                ValidateTestBodyWithQueryParams(user, query);
 
                 FormatTestBodyWithQueryParams(user, ref query);
 
@@ -2023,18 +2023,15 @@ public async Task<ApiResponse<object>> TestEndpointParametersAsync(byte[] varByt
         /// <summary>
         /// Validates the request parameters
         /// </summary>
-        /// <param name="enumHeaderString"></param>
         /// <param name="enumHeaderStringArray"></param>
         /// <param name="enumQueryStringArray"></param>
         /// <param name="enumFormStringArray"></param>
-        /// <param name="enumFormString"></param>
         /// <param name="enumQueryString"></param>
+        /// <param name="enumHeaderString"></param>
+        /// <param name="enumFormString"></param>
         /// <returns></returns>
-        private void ValidateTestEnumParameters(Option<string> enumHeaderString, Option<List<string>> enumHeaderStringArray, Option<List<string>> enumQueryStringArray, Option<List<string>> enumFormStringArray, Option<string> enumFormString, Option<string> enumQueryString)
+        private void ValidateTestEnumParameters(Option<List<string>> enumHeaderStringArray, Option<List<string>> enumQueryStringArray, Option<List<string>> enumFormStringArray, Option<string> enumQueryString, Option<string> enumHeaderString, Option<string> enumFormString)
         {
-            if (enumHeaderString.IsSet && enumHeaderString.Value == null)
-                throw new ArgumentNullException(nameof(enumHeaderString));
-
             if (enumHeaderStringArray.IsSet && enumHeaderStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumHeaderStringArray));
 
@@ -2044,11 +2041,14 @@ private void ValidateTestEnumParameters(Option<string> enumHeaderString, Option<
             if (enumFormStringArray.IsSet && enumFormStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumFormStringArray));
 
-            if (enumFormString.IsSet && enumFormString.Value == null)
-                throw new ArgumentNullException(nameof(enumFormString));
-
             if (enumQueryString.IsSet && enumQueryString.Value == null)
                 throw new ArgumentNullException(nameof(enumQueryString));
+
+            if (enumHeaderString.IsSet && enumHeaderString.Value == null)
+                throw new ArgumentNullException(nameof(enumHeaderString));
+
+            if (enumFormString.IsSet && enumFormString.Value == null)
+                throw new ArgumentNullException(nameof(enumFormString));
         }
 
         /// <summary>
@@ -2167,7 +2167,7 @@ public async Task<ApiResponse<object>> TestEnumParametersAsync(Option<List<strin
 
             try
             {
-                ValidateTestEnumParameters(enumHeaderString, enumHeaderStringArray, enumQueryStringArray, enumFormStringArray, enumFormString, enumQueryString);
+                ValidateTestEnumParameters(enumHeaderStringArray, enumQueryStringArray, enumFormStringArray, enumQueryString, enumHeaderString, enumFormString);
 
                 FormatTestEnumParameters(enumHeaderStringArray, enumQueryStringArray, ref enumQueryDouble, ref enumQueryInteger, enumFormStringArray, ref enumHeaderString, ref enumQueryString, ref enumFormString);
 

samples/client/petstore/csharp/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -2023,30 +2023,30 @@ public async Task<ApiResponse<object>> TestEndpointParametersAsync(byte[] varByt
         /// </summary>
         /// <param name="enumQueryStringArray"></param>
         /// <param name="enumFormStringArray"></param>
-        /// <param name="enumHeaderString"></param>
+        /// <param name="enumQueryString"></param>
         /// <param name="enumHeaderStringArray"></param>
         /// <param name="enumFormString"></param>
-        /// <param name="enumQueryString"></param>
+        /// <param name="enumHeaderString"></param>
         /// <returns></returns>
-        private void ValidateTestEnumParameters(Option<List<string>> enumQueryStringArray, Option<List<string>> enumFormStringArray, Option<string> enumHeaderString, Option<List<string>> enumHeaderStringArray, Option<string> enumFormString, Option<string> enumQueryString)
+        private void ValidateTestEnumParameters(Option<List<string>> enumQueryStringArray, Option<List<string>> enumFormStringArray, Option<string> enumQueryString, Option<List<string>> enumHeaderStringArray, Option<string> enumFormString, Option<string> enumHeaderString)
         {
             if (enumQueryStringArray.IsSet && enumQueryStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumQueryStringArray));
 
             if (enumFormStringArray.IsSet && enumFormStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumFormStringArray));
 
-            if (enumHeaderString.IsSet && enumHeaderString.Value == null)
-                throw new ArgumentNullException(nameof(enumHeaderString));
+            if (enumQueryString.IsSet && enumQueryString.Value == null)
+                throw new ArgumentNullException(nameof(enumQueryString));
 
             if (enumHeaderStringArray.IsSet && enumHeaderStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumHeaderStringArray));
 
             if (enumFormString.IsSet && enumFormString.Value == null)
                 throw new ArgumentNullException(nameof(enumFormString));
 
-            if (enumQueryString.IsSet && enumQueryString.Value == null)
-                throw new ArgumentNullException(nameof(enumQueryString));
+            if (enumHeaderString.IsSet && enumHeaderString.Value == null)
+                throw new ArgumentNullException(nameof(enumHeaderString));
         }
 
         /// <summary>
@@ -2165,7 +2165,7 @@ public async Task<ApiResponse<object>> TestEnumParametersAsync(Option<List<strin
 
             try
             {
-                ValidateTestEnumParameters(enumQueryStringArray, enumFormStringArray, enumHeaderString, enumHeaderStringArray, enumFormString, enumQueryString);
+                ValidateTestEnumParameters(enumQueryStringArray, enumFormStringArray, enumQueryString, enumHeaderStringArray, enumFormString, enumHeaderString);
 
                 FormatTestEnumParameters(enumHeaderStringArray, enumQueryStringArray, ref enumQueryDouble, ref enumQueryInteger, enumFormStringArray, ref enumHeaderString, ref enumQueryString, ref enumFormString);
 

samples/client/petstore/csharp/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -2016,30 +2016,30 @@ public async Task<ApiResponse<object>> TestEndpointParametersAsync(byte[] varByt
         /// </summary>
         /// <param name="enumQueryStringArray"></param>
         /// <param name="enumFormStringArray"></param>
-        /// <param name="enumHeaderString"></param>
+        /// <param name="enumQueryString"></param>
         /// <param name="enumHeaderStringArray"></param>
         /// <param name="enumFormString"></param>
-        /// <param name="enumQueryString"></param>
+        /// <param name="enumHeaderString"></param>
         /// <returns></returns>
-        private void ValidateTestEnumParameters(Option<List<string>> enumQueryStringArray, Option<List<string>> enumFormStringArray, Option<string> enumHeaderString, Option<List<string>> enumHeaderStringArray, Option<string> enumFormString, Option<string> enumQueryString)
+        private void ValidateTestEnumParameters(Option<List<string>> enumQueryStringArray, Option<List<string>> enumFormStringArray, Option<string> enumQueryString, Option<List<string>> enumHeaderStringArray, Option<string> enumFormString, Option<string> enumHeaderString)
         {
             if (enumQueryStringArray.IsSet && enumQueryStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumQueryStringArray));
 
             if (enumFormStringArray.IsSet && enumFormStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumFormStringArray));
 
-            if (enumHeaderString.IsSet && enumHeaderString.Value == null)
-                throw new ArgumentNullException(nameof(enumHeaderString));
+            if (enumQueryString.IsSet && enumQueryString.Value == null)
+                throw new ArgumentNullException(nameof(enumQueryString));
 
             if (enumHeaderStringArray.IsSet && enumHeaderStringArray.Value == null)
                 throw new ArgumentNullException(nameof(enumHeaderStringArray));
 
             if (enumFormString.IsSet && enumFormString.Value == null)
                 throw new ArgumentNullException(nameof(enumFormString));
 
-            if (enumQueryString.IsSet && enumQueryString.Value == null)
-                throw new ArgumentNullException(nameof(enumQueryString));
+            if (enumHeaderString.IsSet && enumHeaderString.Value == null)
+                throw new ArgumentNullException(nameof(enumHeaderString));
         }
 
         /// <summary>
@@ -2158,7 +2158,7 @@ public async Task<ApiResponse<object>> TestEnumParametersAsync(Option<List<strin
 
             try
             {
-                ValidateTestEnumParameters(enumQueryStringArray, enumFormStringArray, enumHeaderString, enumHeaderStringArray, enumFormString, enumQueryString);
+                ValidateTestEnumParameters(enumQueryStringArray, enumFormStringArray, enumQueryString, enumHeaderStringArray, enumFormString, enumHeaderString);
 
                 FormatTestEnumParameters(enumHeaderStringArray, enumQueryStringArray, ref enumQueryDouble, ref enumQueryInteger, enumFormStringArray, ref enumHeaderString, ref enumQueryString, ref enumFormString);