Fix ClassCastException in OpenAPINormalizer on composed schemas in 3.1 (OpenAPITools#17912)

Author: bjansen

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

@@ -458,33 +458,31 @@ public Schema normalizeSchema(Schema schema, Set<Schema> visitedSchemas) {
         } else if (ModelUtils.isAllOf(schema)) { // allOf
             return normalizeAllOf(schema, visitedSchemas);
         } else if (ModelUtils.isComposedSchema(schema)) { // composed schema
-            ComposedSchema cs = (ComposedSchema) schema;
-
-            if (ModelUtils.isComplexComposedSchema(cs)) {
-                cs = (ComposedSchema) normalizeComplexComposedSchema(cs, visitedSchemas);
+            if (ModelUtils.isComplexComposedSchema(schema)) {
+                schema = normalizeComplexComposedSchema(schema, visitedSchemas);
             }
 
-            if (cs.getAllOf() != null && !cs.getAllOf().isEmpty()) {
-                return normalizeAllOf(cs, visitedSchemas);
+            if (schema.getAllOf() != null && !schema.getAllOf().isEmpty()) {
+                return normalizeAllOf(schema, visitedSchemas);
             }
 
-            if (cs.getOneOf() != null && !cs.getOneOf().isEmpty()) {
-                return normalizeOneOf(cs, visitedSchemas);
+            if (schema.getOneOf() != null && !schema.getOneOf().isEmpty()) {
+                return normalizeOneOf(schema, visitedSchemas);
             }
 
-            if (cs.getAnyOf() != null && !cs.getAnyOf().isEmpty()) {
-                return normalizeAnyOf(cs, visitedSchemas);
+            if (schema.getAnyOf() != null && !schema.getAnyOf().isEmpty()) {
+                return normalizeAnyOf(schema, visitedSchemas);
             }
 
-            if (cs.getProperties() != null && !cs.getProperties().isEmpty()) {
-                normalizeProperties(cs.getProperties(), visitedSchemas);
+            if (schema.getProperties() != null && !schema.getProperties().isEmpty()) {
+                normalizeProperties(schema.getProperties(), visitedSchemas);
             }
 
-            if (cs.getAdditionalProperties() != null) {
+            if (schema.getAdditionalProperties() != null) {
                 // normalizeAdditionalProperties(m);
             }
 
-            return cs;
+            return schema;
         } else if (schema.getProperties() != null && !schema.getProperties().isEmpty()) {
             normalizeProperties(schema.getProperties(), visitedSchemas);
         } else if (schema instanceof BooleanSchema) {

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

@@ -467,4 +467,12 @@ public void testFilter() {
         assertEquals(openAPI.getPaths().get("/person/display/{personId}").getDelete().getExtensions().get("x-internal"), false);
         assertEquals(openAPI.getPaths().get("/person/display/{personId}").getPut().getExtensions().get("x-internal"), true);
     }
-}
+
+    @Test
+    public void testComposedSchemaDoesNotThrow() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_1/composed-schema.yaml");
+
+        OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, Collections.emptyMap());
+        openAPINormalizer.normalize();
+    }
+}

modules/openapi-generator/src/test/resources/3_1/composed-schema.yaml

@@ -0,0 +1,36 @@
+openapi: 3.1.0
+info:
+  version: 1.0.0
+  title: Example
+  license:
+    name: MIT
+servers:
+  - url: http://api.example.xyz/v1
+paths:
+  /payment:
+    post:
+      operationId: payment
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/Payment"
+
+components:
+  schemas:
+    Payment:
+      type: object
+      properties:
+        label:
+          type: string
+        otherLabel:
+          type: string
+        amount:
+          type: number
+      oneOf:
+        - required:
+            - label
+            - amount
+        - required:
+            - otherLabel
+            - amount