Better handling of metadata in allOf

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

@@ -418,18 +418,7 @@ private void gatherInlineModels(Schema schema, String modelPrefix) {
                     if (schema.getAllOf().size() == 1) {
                         // handle earlier in this function when looping through properties
                     } else if (schema.getAllOf().size() > 1) {
-                        // Check if there is only one "non metadata" schema.
-                        // For example, there may be an `description` only schema that is used to override the descrption.
-                        // In these cases, we can simply discard those schemas.
-                        List<Schema> nonMetadataOnlySchemas = (List<Schema>) schema.getAllOf().stream()
-                                .filter(v -> ModelUtils.isMetadataOnlySchema((Schema) v))
-                                .collect(Collectors.toList());
-
-                        if (nonMetadataOnlySchemas.size() == 1) {
-                            schema.setAllOf(nonMetadataOnlySchemas);
-                        } else {
-                            LOGGER.warn("allOf schema `{}` containing multiple types (not model) is not supported at the moment.", schema.getName());
-                        }
+                        LOGGER.warn("allOf schema `{}` containing multiple types (not model) is not supported at the moment.", schema.getName());
                     } else {
                         LOGGER.error("allOf schema `{}` contains no items.", schema.getName());
                     }

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

@@ -851,6 +851,52 @@ protected void normalizeProperties(Map<String, Schema> properties, Set<Schema> v
         }
     }
 
+    protected void refactorAllOfWithMetadataOnlySchemas(Schema schema) {
+        if (schema.getAllOf() == null) {
+            return;
+        }
+
+        // Check if there are metadata schemas.
+        // For example, there may be an `description` only schema that is used to override the descrption.
+        List<Schema> nonMetadataOnlySchemas = new ArrayList<>();
+        List<Schema> metadataOnlySchemas = new ArrayList<>();
+
+        for (Object s: schema.getAllOf()) {
+            if (s instanceof Schema) {
+                if (ModelUtils.isMetadataOnlySchema((Schema) s)) {
+                    metadataOnlySchemas.add((Schema) s);
+                } else {
+                    nonMetadataOnlySchemas.add((Schema) s);
+                }
+            }
+        }
+
+        //      ReferenceNumber:
+        //       allOf:
+        //       - $ref: '#/components/schemas/IEAN8'
+        //       - description: Product Ref
+        //       - example: IEAN1234
+        //
+        // becomes the following after the following code block
+        //
+        //     ReferenceNumber:
+        //      allOf:
+        //      - $ref: '#/components/schemas/IEAN8'
+        //      description: Product Ref
+        //      example: IEAN1234
+        //
+        // which can be further processed by the generator
+        if (nonMetadataOnlySchemas.size() > 0) {
+            // keep the non metadata schema(s)
+            schema.setAllOf(nonMetadataOnlySchemas);
+
+            // copy metadata to the allOf schema
+            for (Schema metadataOnlySchema: metadataOnlySchemas) {
+                ModelUtils.copyMetadata(metadataOnlySchema, schema);
+            }
+        }
+    }
+
     /*
      * Remove unsupported schemas (e.g. if, then) from allOf.
      *
@@ -882,6 +928,8 @@ protected void removeUnsupportedSchemasFromAllOf(Schema schema) {
     protected Schema normalizeAllOf(Schema schema, Set<Schema> visitedSchemas) {
         removeUnsupportedSchemasFromAllOf(schema);
 
+        refactorAllOfWithMetadataOnlySchemas(schema);
+
         if (schema.getAllOf() == null) {
             return schema;
         }

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

@@ -2353,6 +2353,63 @@ public static boolean isUnsupportedSchema(OpenAPI openAPI, Schema schema) {
         return false;
     }
 
+    /**
+     * Copy meta data (e.g. description, default, examples, etc) from one schema to another.
+     *
+     * @param from  From schema
+     * @param to    To schema
+     */
+    public static void copyMetadata(Schema from, Schema to) {
+        if (from.getDescription() != null) {
+            to.setDescription(from.getDescription());
+        }
+        if (from.getDefault() != null) {
+            to.setDefault(from.getDefault());
+        }
+        if (from.getDeprecated() != null) {
+            to.setDeprecated(from.getDeprecated());
+        }
+        if (from.getNullable() != null) {
+            to.setNullable(from.getNullable());
+        }
+        if (from.getExample() != null) {
+            to.setExample(from.getExample());
+        }
+        if (from.getExamples() != null) {
+            to.setExample(from.getExamples());
+        }
+        if (from.getReadOnly() != null) {
+            to.setReadOnly(from.getReadOnly());
+        }
+        if (from.getWriteOnly() != null) {
+            to.setWriteOnly(from.getWriteOnly());
+        }
+        if (from.getExtensions() != null) {
+            to.setExtensions(from.getExtensions());
+        }
+        if (from.getMaxLength() != null) {
+            to.setMaxLength(from.getMaxLength());
+        }
+        if (from.getMinLength() != null) {
+            to.setMinLength(from.getMinLength());
+        }
+        if (from.getMaxItems() != null) {
+            to.setMaxItems(from.getMaxItems());
+        }
+        if (from.getMinItems() != null) {
+            to.setMinItems(from.getMinItems());
+        }
+        if (from.getMaximum() != null) {
+            to.setMaximum(from.getMaximum());
+        }
+        if (from.getMinimum() != null) {
+            to.setMinimum(from.getMinimum());
+        }
+        if (from.getTitle() != null) {
+            to.setTitle(from.getTitle());
+        }
+    }
+
     /**
      * Returns true if a schema is only metadata and not an actual type.
      * For example, a schema that only has a `description` without any `properties` or `$ref` defined.
@@ -2361,7 +2418,7 @@ public static boolean isUnsupportedSchema(OpenAPI openAPI, Schema schema) {
      * @return       if the schema is only metadata and not an actual type
      */
     public static boolean isMetadataOnlySchema(Schema schema) {
-        return schema.get$ref() != null ||
+        return !(schema.get$ref() != null ||
                 schema.getProperties() != null ||
                 schema.getType() != null ||
                 schema.getAdditionalProperties() != null ||
@@ -2375,7 +2432,7 @@ public static boolean isMetadataOnlySchema(Schema schema) {
                 schema.getContains() != null ||
                 schema.get$dynamicAnchor() != null ||
                 schema.get$anchor() != null ||
-                schema.getContentSchema() != null;
+                schema.getContentSchema() != null);
     }
 
 

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

@@ -79,6 +79,25 @@ public void testOpenAPINormalizerRefAsParentInAllOfAndRefactorAllOfWithPropertie
         assertNull(schema4.getExtensions());
     }
 
+    @Test
+    public void testOpenAPINormalizerRefactorAllofWithMetadataOnlySchemas() {
+        // to test the rule REF_AS_PARENT_IN_ALLOF
+        OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/allof_with_metadata_only_schemas.yaml");
+
+        Schema schema = openAPI.getComponents().getSchemas().get("ReferenceNumber");
+        assertEquals(schema.getAllOf().size(), 3);
+        assertEquals(((Schema) schema.getAllOf().get(2)).getExample(), "IEAN1234");
+
+        Map<String, String> options = new HashMap<>();
+        OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
+        openAPINormalizer.normalize();
+
+        Schema schema2 = openAPI.getComponents().getSchemas().get("ReferenceNumber");
+        assertEquals(schema2.getAllOf().size(), 1);
+        assertEquals(schema2.getExample(), "IEAN1234");
+        assertEquals(((Schema) schema2.getAllOf().get(0)).get$ref(), "#/components/schemas/IEAN8");
+    }
+
     @Test
     public void testOpenAPINormalizerEnableKeepOnlyFirstTagInOperation() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/enableKeepOnlyFirstTagInOperation_test.yaml");

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

@@ -0,0 +1,47 @@
+openapi: 3.0.3
+info:
+  version: 1.0.0
+  title: Test
+paths:
+  /api/productRef:
+    get:
+      operationId: getProductRef
+      summary: Retrieve product reference
+      description: Returns a product reference based on a given product.
+      responses:
+        '200':
+          description: Successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ProductType'
+components:
+  schemas:
+    ProductType:
+      type: object
+      required:
+        - referenceNumber
+      properties:
+        referenceNumber:
+            $ref: "#/components/schemas/ReferenceNumber"
+    ReferenceNumber:
+      allOf:
+        - $ref: "#/components/schemas/IEAN8"
+        - description: Product Ref
+        - example: IEAN1234
+    IEAN8:
+      type: string
+      minLength: 8
+      maxLength: 8
+      example: "IEAN1234"
+    Order:
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+        foo:
+          allOf:
+            - $ref: '#/components/schemas/ProductType'
+            - description: 'this is foo'
+            - example: 'this is bar'

samples/client/petstore/rust/hyper/petstore/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/hyper/petstore/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/hyper0x/petstore/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/hyper0x/petstore/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest-trait/petstore/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest-trait/petstore/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest/petstore-async-middleware/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest/petstore-async/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest/petstore-async/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest/petstore-avoid-box/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/TestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/models/test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct TestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }

samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FooTestAllOfWithMultiMetadataOnly.md

@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **id** | Option<**i64**> |  | [optional]
-**foo** | Option<**Vec<String>**> | existing_tags_array | [optional]
+**foo** | Option<**Vec<String>**> | This is a test for allOf with metadata only fields | [optional]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 

samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/models/foo_test_all_of_with_multi_metadata_only.rs

@@ -15,7 +15,7 @@ use serde::{Deserialize, Serialize};
 pub struct FooTestAllOfWithMultiMetadataOnly {
     #[serde(rename = "id", skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
-    /// existing_tags_array
+    /// This is a test for allOf with metadata only fields
     #[serde(rename = "foo", default, with = "::serde_with::rust::double_option", skip_serializing_if = "Option::is_none")]
     pub foo: Option<Option<Vec<String>>>,
 }