Handle different use cases of mappings

Author: david-marconis

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

@@ -439,9 +439,19 @@ public CodegenModel fromModel(String name, Schema model) {
                 }
 
                 for (final CodegenProperty property : codegenModel.readWriteVars) {
-                    if (property.defaultValue == null && parentCodegenModel.discriminator != null && property.name.equals(parentCodegenModel.discriminator.getPropertyName())) {
-                        if (parentCodegenModel.discriminator.getIsEnum()) {
-                            property.defaultValue = toEnumDefaultValue(property, name);
+                    CodegenDiscriminator discriminator = parentCodegenModel.discriminator;
+                    if (property.defaultValue == null && discriminator != null && property.name.equals(discriminator.getPropertyName())) {
+                        if (discriminator.getIsEnum()) {
+                            String enumValue = name;
+                            Map<String, String> mapping = Optional.ofNullable(discriminator.getMapping()).orElseGet(Collections::emptyMap);
+                            for (Map.Entry<String, String> e : mapping.entrySet()) {
+                                String schemaName = e.getValue().indexOf('/') < 0 ? e.getValue() : ModelUtils.getSimpleRef(e.getValue());
+                                if (name.equals(schemaName)) {
+                                    enumValue = e.getKey();
+                                    break;
+                                }
+                            }
+                            property.defaultValue = toEnumDefaultValue(property, enumValue);
                         } else {
                             property.defaultValue = "\"" + name + "\"";
                         }

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

@@ -146,7 +146,7 @@ public void testEnumDiscriminatorDefaultValueIsNotString() throws IOException {
         File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
         output.deleteOnExit();
         final OpenAPI openAPI = TestUtils.parseFlattenSpec(
-            "src/test/resources/3_0/enum_discriminator_inheritance.yaml");
+                "src/test/resources/3_0/enum_discriminator_inheritance.yaml");
         final DefaultGenerator defaultGenerator = new DefaultGenerator();
         final ClientOptInput clientOptInput = new ClientOptInput();
         clientOptInput.openAPI(openAPI);
@@ -156,14 +156,23 @@ public void testEnumDiscriminatorDefaultValueIsNotString() throws IOException {
         clientOptInput.config(cSharpClientCodegen);
         defaultGenerator.opts(clientOptInput);
 
-      Map<String, File> files = defaultGenerator.generate().stream()
-            .collect(Collectors.toMap(File::getPath, Function.identity()));
+        Map<String, File> files = defaultGenerator.generate().stream()
+                .collect(Collectors.toMap(File::getPath, Function.identity()));
 
-        File modelFile = files.get(Paths
-            .get(output.getAbsolutePath(), "src", "Org.OpenAPITools", "Model", "Cat.cs")
-            .toString()
+        Map<String, String> expectedMapping = Map.of(
+                "Catty", "Cat",
+                "Lizzy", "Lizard",
+                "Dog", "Dog"
         );
-        assertNotNull(modelFile);
-        assertFileContains(modelFile.toPath(), "AnimalType petType = AnimalType.Cat");
+        for (Map.Entry<String, String> e : expectedMapping.entrySet()) {
+            String modelName = e.getValue();
+            String enumValue = e.getKey();
+            File file = files.get(Paths
+                    .get(output.getAbsolutePath(), "src", "Org.OpenAPITools", "Model", modelName + ".cs")
+                    .toString()
+            );
+            assertNotNull(file, "Could not find file for model: " + modelName);
+            assertFileContains(file.toPath(), "AnimalType petType = AnimalType." + enumValue);
+        }
     }
 }

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

@@ -21,13 +21,17 @@ components:
           $ref: '#/components/schemas/AnimalType'
       discriminator:
         propertyName: petType
+        # Mapping with implicit (Dog), explicit ref (Catty -> Cat), and explicit schema name (Lizzy -> Lizard)
+        mapping:
+          Catty: '#/components/schemas/Cat'
+          Lizzy: 'Lizard'
       required:
         - petType
     AnimalType:
       type: string
       enum:
         - Dog
-        - Cat
+        - Catty
     Cat:
       type: object
       allOf:
@@ -42,3 +46,10 @@ components:
       properties:
         bark:
           type: string
+    Lizard:
+      type: object
+      allOf:
+        - $ref: '#/components/schemas/Animal'
+      properties:
+        lovesRocks:
+          type: string