Fix anyOf/oneOf normalization for 3.1 spec

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

@@ -516,7 +516,7 @@ public Schema normalizeSchema(Schema schema, Set<Schema> visitedSchemas) {
             return schema;
         }
 
-        if ((visitedSchemas.contains(schema))) {
+        if (visitedSchemas.contains(schema)) {
             return schema; // skip due to circular reference
         } else {
             visitedSchemas.add(schema);
@@ -535,7 +535,6 @@ public Schema normalizeSchema(Schema schema, Set<Schema> visitedSchemas) {
             return normalizeAnyOf(schema, visitedSchemas);
         } else if (ModelUtils.isAllOfWithProperties(schema)) { // allOf with properties
             schema = normalizeAllOfWithProperties(schema, visitedSchemas);
-            normalizeSchema(schema, visitedSchemas);
         } else if (ModelUtils.isAllOf(schema)) { // allOf
             return normalizeAllOf(schema, visitedSchemas);
         } else if (ModelUtils.isComposedSchema(schema)) { // composed schema
@@ -643,15 +642,19 @@ private Schema normalizeAllOfWithProperties(Schema schema, Set<Schema> visitedSc
     }
 
     private Schema normalizeOneOf(Schema schema, Set<Schema> visitedSchemas) {
-        for (Object item : schema.getOneOf()) {
+        for (int i = 0; i < schema.getOneOf().size(); i++) {
+            // normalize oneOf sub schemas one by one
+            Object item = schema.getOneOf().get(i);
+
             if (item == null) {
                 continue;
             }
             if (!(item instanceof Schema)) {
                 throw new RuntimeException("Error! oneOf schema is not of the type Schema: " + item);
             }
-            // normalize oenOf sub schemas one by one
-            normalizeSchema((Schema) item, visitedSchemas);
+
+            // update sub-schema with the updated schema
+            schema.getOneOf().set(i, normalizeSchema((Schema) item, visitedSchemas));
         }
         // process rules here
         schema = processSimplifyOneOf(schema);
@@ -660,16 +663,20 @@ private Schema normalizeOneOf(Schema schema, Set<Schema> visitedSchemas) {
     }
 
     private Schema normalizeAnyOf(Schema schema, Set<Schema> visitedSchemas) {
-        for (Object item : schema.getAnyOf()) {
+        for (int i = 0; i < schema.getAnyOf().size(); i++) {
+            // normalize anyOf sub schemas one by one
+            Object item = schema.getAnyOf().get(i);
+
             if (item == null) {
                 continue;
             }
 
             if (!(item instanceof Schema)) {
                 throw new RuntimeException("Error! anyOf schema is not of the type Schema: " + item);
             }
-            // normalize anyOf sub schemas one by one
-            normalizeSchema((Schema) item, visitedSchemas);
+
+            // update sub-schema with the updated schema
+            schema.getAnyOf().set(i, normalizeSchema((Schema) item, visitedSchemas));
         }
 
         // process rules here

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

@@ -600,7 +600,9 @@ public static Schema<?> getSchemaItems(Schema schema) {
         Schema<?> items = schema.getItems();
         if (items == null) {
             if (schema instanceof JsonSchema) { // 3.1 spec
-                // do nothing as the schema may contain prefixItems only
+                // set the items to a new schema (any type)
+                items = new Schema<>();
+                schema.setItems(items);
             } else { // 3.0 spec, default to string
                 LOGGER.error("Undefined array inner type for `{}`. Default to String.", schema.getName());
                 items = new StringSchema().description("TODO default missing array inner type to string");

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

@@ -605,6 +605,16 @@ public void testOpenAPINormalizerProcessingArraySchema31Spec() {
         assertNotEquals(((Schema) schema7.getProperties().get("with_prefixitems")).getPrefixItems(), null);
         assertEquals(((Schema) schema7.getProperties().get("without_items")).getItems(), null);
 
+        Schema schema9 = openAPI.getComponents().getSchemas().get("AnyOfArrayWithPrefixItems");
+        assertEquals(((Schema) schema9.getAnyOf().get(0)).getItems(), null);
+        assertNotEquals(((Schema) schema9.getAnyOf().get(0)).getPrefixItems(), null);
+        assertEquals(((Schema) schema9.getAnyOf().get(1)).getItems(), null);
+
+        Schema schema11 = openAPI.getComponents().getSchemas().get("OneOfArrayWithPrefixItems");
+        assertEquals(((Schema) schema11.getOneOf().get(0)).getItems(), null);
+        assertNotEquals(((Schema) schema11.getOneOf().get(0)).getPrefixItems(), null);
+        assertEquals(((Schema) schema11.getOneOf().get(1)).getItems(), null);
+
         Map<String, String> inputRules = Map.of("NORMALIZE_31SPEC", "true");
         OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, inputRules);
         openAPINormalizer.normalize();
@@ -632,6 +642,16 @@ public void testOpenAPINormalizerProcessingArraySchema31Spec() {
         assertNotEquals(((Schema) schema8.getProperties().get("with_prefixitems")).getItems(), null);
         assertEquals(((Schema) schema8.getProperties().get("with_prefixitems")).getPrefixItems(), null);
         assertNotEquals(((Schema) schema8.getProperties().get("without_items")).getItems(), null);
+
+        Schema schema10 = openAPI.getComponents().getSchemas().get("AnyOfArrayWithPrefixItems");
+        assertNotEquals(((Schema) schema10.getAnyOf().get(0)).getItems(), null);
+        assertEquals(((Schema) schema10.getAnyOf().get(0)).getPrefixItems(), null);
+        assertNotEquals(((Schema) schema10.getAnyOf().get(1)).getItems(), null);
+
+        Schema schema12 = openAPI.getComponents().getSchemas().get("OneOfArrayWithPrefixItems");
+        assertNotEquals(((Schema) schema12.getOneOf().get(0)).getItems(), null);
+        assertEquals(((Schema) schema12.getOneOf().get(0)).getPrefixItems(), null);
+        assertNotEquals(((Schema) schema12.getOneOf().get(1)).getItems(), null);
     }
 
     @Test

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

@@ -461,4 +461,12 @@ public void testCloneDateTimeSchemaWithExample() {
         Assert.assertEquals(deepCopy, schema);
         Assert.assertNotSame(deepCopy, schema);
     }
+
+    @Test
+    public void testGetSchemaItemsWith31Spec() {
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_1/issue_18291.yaml");
+        Schema arrayWithPrefixItems = ModelUtils.getSchema(openAPI, "ArrayWithPrefixItems");
+        Assert.assertNotNull(ModelUtils.getSchemaItems((Schema) arrayWithPrefixItems.getProperties().get("with_prefixitems")));
+        Assert.assertNotNull(ModelUtils.getSchemaItems((Schema) arrayWithPrefixItems.getProperties().get("without_items")));
+    }
 }

modules/openapi-generator/src/test/resources/3_1/issue_18291.yaml

@@ -47,3 +47,23 @@ components:
           minItems: 2
         without_items:
           type: array
+    AnyOfArrayWithPrefixItems:
+      anyOf:
+        - type: array
+          prefixItems:
+            - type: number
+              title: Longitude
+            - type: number
+              title: Latitude
+          maxItems: 2
+          minItems: 2
+        - type: array
+    OneOfArrayWithPrefixItems:
+      oneOf:
+        - type: array
+          prefixItems:
+            - type: integer
+            - type: integer
+          maxItems: 3
+          minItems: 3
+        - type: array

samples/client/petstore/java/okhttp-gson-3.1/api/openapi.yaml

@@ -815,6 +815,7 @@ paths:
                 items:
                   $ref: '#/components/schemas/myObject'
                 nullable: true
+                type: array
           description: ""
       tags:
       - fake
@@ -1185,6 +1186,7 @@ components:
       - type: string
       - items:
           type: string
+        type: array
   securitySchemes:
     petstore_auth:
       flows: