feat!: add discriminator support for OpenAPI v3 and Swagger v2

src/interpreter/InterpretAllOf.ts

@@ -1,5 +1,10 @@
 import { Logger } from '../utils';
-import { CommonModel, AsyncapiV2Schema } from '../models';
+import {
+  CommonModel,
+  AsyncapiV2Schema,
+  SwaggerV2Schema,
+  OpenapiV3Schema
+} from '../models';
 import {
   Interpreter,
   InterpreterOptions,
@@ -33,13 +38,28 @@ export default function interpretAllOf(
   }
 
   for (const allOfSchema of schema.allOf) {
-    if (allOfSchema instanceof AsyncapiV2Schema && allOfSchema.discriminator) {
+    if (
+      (allOfSchema instanceof AsyncapiV2Schema ||
+        allOfSchema instanceof SwaggerV2Schema) &&
+      allOfSchema.discriminator
+    ) {
       interpreterOptions = {
         ...interpreterOptions,
         discriminator: allOfSchema.discriminator
       };
 
       model.discriminator = allOfSchema.discriminator;
+    } else if (
+      allOfSchema instanceof OpenapiV3Schema &&
+      allOfSchema.discriminator &&
+      allOfSchema.discriminator.propertyName
+    ) {
+      interpreterOptions = {
+        ...interpreterOptions,
+        discriminator: allOfSchema.discriminator.propertyName
+      };
+
+      model.discriminator = allOfSchema.discriminator.propertyName;
     }
   }
 

src/interpreter/InterpretConst.ts

@@ -1,4 +1,10 @@
-import { Draft4Schema, CommonModel, AsyncapiV2Schema } from '../models';
+import {
+  Draft4Schema,
+  CommonModel,
+  AsyncapiV2Schema,
+  SwaggerV2Schema,
+  OpenapiV3Schema
+} from '../models';
 import {
   Interpreter,
   InterpreterOptions,
@@ -26,7 +32,12 @@ export default function interpretConst(
     return;
   }
 
-  if (schema instanceof AsyncapiV2Schema && interpreterOptions.discriminator) {
+  if (
+    (schema instanceof AsyncapiV2Schema ||
+      schema instanceof SwaggerV2Schema ||
+      schema instanceof OpenapiV3Schema) &&
+    interpreterOptions.discriminator
+  ) {
     model.enum = [schema.const];
   }
 

src/interpreter/InterpretOneOf.ts

@@ -1,4 +1,9 @@
-import { AsyncapiV2Schema, CommonModel } from '../models';
+import {
+  AsyncapiV2Schema,
+  CommonModel,
+  OpenapiV3Schema,
+  SwaggerV2Schema
+} from '../models';
 import {
   Interpreter,
   InterpreterOptions,
@@ -30,13 +35,27 @@ export default function interpretOneOf(
     return;
   }
 
-  if (schema instanceof AsyncapiV2Schema && schema.discriminator) {
+  if (
+    (schema instanceof AsyncapiV2Schema || schema instanceof SwaggerV2Schema) &&
+    schema.discriminator
+  ) {
     interpreterOptions = {
       ...interpreterOptions,
       discriminator: schema.discriminator
     };
 
     model.discriminator = schema.discriminator;
+  } else if (
+    schema instanceof OpenapiV3Schema &&
+    schema.discriminator &&
+    schema.discriminator.propertyName
+  ) {
+    interpreterOptions = {
+      ...interpreterOptions,
+      discriminator: schema.discriminator.propertyName
+    };
+
+    model.discriminator = schema.discriminator.propertyName;
   }
 
   for (const oneOfSchema of schema.oneOf) {

src/interpreter/InterpretOneOfWithAllOf.ts

@@ -1,4 +1,9 @@
-import { CommonModel, AsyncapiV2Schema } from '../models';
+import {
+  CommonModel,
+  AsyncapiV2Schema,
+  OpenapiV3Schema,
+  SwaggerV2Schema
+} from '../models';
 import {
   Interpreter,
   InterpreterOptions,
@@ -32,13 +37,28 @@ export default function interpretOneOfWithAllOf(
   }
 
   for (const allOfSchema of schema.allOf) {
-    if (allOfSchema instanceof AsyncapiV2Schema && allOfSchema.discriminator) {
+    if (
+      (allOfSchema instanceof AsyncapiV2Schema ||
+        allOfSchema instanceof SwaggerV2Schema) &&
+      allOfSchema.discriminator
+    ) {
       interpreterOptions = {
         ...interpreterOptions,
         discriminator: allOfSchema.discriminator
       };
 
       model.discriminator = allOfSchema.discriminator;
+    } else if (
+      allOfSchema instanceof OpenapiV3Schema &&
+      allOfSchema.discriminator &&
+      allOfSchema.discriminator.propertyName
+    ) {
+      interpreterOptions = {
+        ...interpreterOptions,
+        discriminator: allOfSchema.discriminator.propertyName
+      };
+
+      model.discriminator = allOfSchema.discriminator.propertyName;
     }
   }
 

src/interpreter/InterpretOneOfWithProperties.ts

@@ -1,4 +1,9 @@
-import { CommonModel, AsyncapiV2Schema } from '../models';
+import {
+  CommonModel,
+  AsyncapiV2Schema,
+  OpenapiV3Schema,
+  SwaggerV2Schema
+} from '../models';
 import {
   Interpreter,
   InterpreterOptions,
@@ -30,13 +35,27 @@ export default function interpretOneOfWithProperties(
     return;
   }
 
-  if (schema instanceof AsyncapiV2Schema && schema.discriminator) {
+  if (
+    (schema instanceof AsyncapiV2Schema || schema instanceof SwaggerV2Schema) &&
+    schema.discriminator
+  ) {
     interpreterOptions = {
       ...interpreterOptions,
       discriminator: schema.discriminator
     };
 
     model.discriminator = schema.discriminator;
+  } else if (
+    schema instanceof OpenapiV3Schema &&
+    schema.discriminator &&
+    schema.discriminator.propertyName
+  ) {
+    interpreterOptions = {
+      ...interpreterOptions,
+      discriminator: schema.discriminator.propertyName
+    };
+
+    model.discriminator = schema.discriminator.propertyName;
   }
 
   for (const oneOfSchema of schema.oneOf) {

src/interpreter/Interpreter.ts

@@ -6,7 +6,8 @@ import {
   AsyncapiV2Schema,
   Draft7Schema,
   MergingOptions,
-  defaultMergingOptions
+  defaultMergingOptions,
+  OpenapiV3Schema
 } from '../models';
 import { interpretName } from './Utils';
 import interpretProperties from './InterpretProperties';
@@ -46,7 +47,7 @@ export type InterpreterOptions = {
    */
   ignoreAdditionalItems?: boolean;
   /**
-   * When interpreting a schema with discriminator set, this property will be set bet by the individual interpreters to make sure the discriminator becomes an enum.
+   * When interpreting a schema with discriminator set, this property will be set best by the individual interpreters to make sure the discriminator becomes an enum.
    */
   discriminator?: string;
 };
@@ -55,6 +56,7 @@ export type InterpreterSchemas =
   | Draft4Schema
   | Draft7Schema
   | SwaggerV2Schema
+  | OpenapiV3Schema
   | AsyncapiV2Schema;
 export type InterpreterSchemaType = InterpreterSchemas | boolean;
 

src/processors/JsonSchemaInputProcessor.ts

@@ -476,6 +476,7 @@ export class JsonSchemaInputProcessor extends AbstractInputProcessor {
       | Draft6Schema
       | Draft7Schema
       | SwaggerV2Schema
+      | OpenapiV3Schema
       | AsyncapiV2Schema
       | boolean,
     options?: ProcessorOptions

src/processors/OpenAPIInputProcessor.ts

@@ -222,14 +222,14 @@ export class OpenAPIInputProcessor extends AbstractInputProcessor {
     schema: OpenAPIV3.SchemaObject,
     name: string
   ): OpenapiV3Schema {
-    let internalSchema = OpenapiV3Schema.toSchema(schema as any);
-    internalSchema = JsonSchemaInputProcessor.reflectSchemaNames(
-      internalSchema,
+    const namedSchema = JsonSchemaInputProcessor.reflectSchemaNames(
+      schema,
       {},
       name,
       true
     );
-    return internalSchema;
+
+    return OpenapiV3Schema.toSchema(namedSchema);
   }
 
   /**

test/generators/java/presets/JacksonPreset.spec.ts

@@ -45,7 +45,7 @@ describe('JAVA_JACKSON_PRESET', () => {
   });
 
   describe('union', () => {
-    test('handle oneOf with discriminator with Jackson', async () => {
+    test('handle oneOf with AsyncAPI discriminator with Jackson', async () => {
       const asyncapiDoc = {
         asyncapi: '2.6.0',
         info: {
@@ -91,6 +91,112 @@ describe('JAVA_JACKSON_PRESET', () => {
       expect(models.map((model) => model.result)).toMatchSnapshot();
     });
 
+    test('handle oneOf with Swagger v2 discriminator with Jackson', async () => {
+      const openapiDoc = {
+        swagger: '2.0',
+        info: {
+          title: 'Vehicle',
+          version: '1.0.0'
+        },
+        paths: {
+          '/vehicles': {
+            get: {
+              responses: {
+                200: {
+                  description: 'successful operation',
+                  schema: {
+                    type: 'object',
+                    title: 'Vehicle',
+                    discriminator: 'vehicleType',
+                    oneOf: [
+                      { $ref: '#/components/schemas/Car' },
+                      { $ref: '#/components/schemas/Truck' }
+                    ]
+                  }
+                }
+              }
+            }
+          }
+        },
+        components: {
+          schemas: {
+            Car: {
+              title: 'Car',
+              type: 'object',
+              properties: {
+                vehicleType: { type: 'string' }
+              }
+            },
+            Truck: {
+              title: 'Truck',
+              type: 'object',
+              properties: {
+                vehicleType: { type: 'string' }
+              }
+            }
+          }
+        }
+      };
+
+      const models = await generator.generate(openapiDoc);
+      expect(models.map((model) => model.result)).toMatchSnapshot();
+    });
+
+    test('handle oneOf with OpenAPI v3 discriminator with Jackson', async () => {
+      const openapiDoc = {
+        openapi: '3.0.3',
+        info: {
+          title: 'Vehicle',
+          version: '1.0.0'
+        },
+        paths: {
+          '/vehicles': {
+            get: {
+              responses: {
+                200: {
+                  description: 'successful operation',
+                  content: {
+                    'application/json': {
+                      schema: {
+                        type: 'object',
+                        title: 'Vehicle',
+                        discriminator: { propertyName: 'vehicleType' },
+                        oneOf: [
+                          { $ref: '#/components/schemas/Car' },
+                          { $ref: '#/components/schemas/Truck' }
+                        ]
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        },
+        components: {
+          schemas: {
+            Car: {
+              title: 'Car',
+              type: 'object',
+              properties: {
+                vehicleType: { type: 'string' }
+              }
+            },
+            Truck: {
+              title: 'Truck',
+              type: 'object',
+              properties: {
+                vehicleType: { type: 'string' }
+              }
+            }
+          }
+        }
+      };
+
+      const models = await generator.generate(openapiDoc);
+      expect(models.map((model) => model.result)).toMatchSnapshot();
+    });
+
     test('handle oneOf without discriminator with Jackson deduction', async () => {
       const jsonSchemaDraft7 = {
         $schema: 'http://json-schema.org/draft-07/schema#',