Remove duplicate oneOf schemas during pre-processing

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

@@ -1009,6 +1009,14 @@ public void postProcessParameter(CodegenParameter parameter) {
     @Override
     @SuppressWarnings("unused")
     public void preprocessOpenAPI(OpenAPI openAPI) {
+        if (openAPI.getComponents() != null && openAPI.getComponents().getSchemas() != null) {
+            // Remove duplicate oneOf
+            Map<String, Schema> schemas = new HashMap<>(openAPI.getComponents().getSchemas());
+            for (var schema : schemas.values()) {
+                ModelUtils.deduplicateOneOfSchema(schema);
+            }
+        }
+
         if (useOneOfInterfaces && openAPI.getComponents() != null) {
             // we process the openapi schema here to find oneOf schemas and create interface models for them
             Map<String, Schema> schemas = new HashMap<>(openAPI.getComponents().getSchemas());

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

@@ -2243,6 +2243,23 @@ public static Schema simplyOneOfAnyOfWithOnlyOneNonNullSubSchema(OpenAPI openAPI
         return schema;
     }
 
+    /**
+     * Removes duplicate `oneOf` from a given schema if it does not also have a discriminator.
+     *
+     * @param schema Schema
+     */
+    public static void deduplicateOneOfSchema(Schema<?> schema) {
+        if (schema.getOneOf() == null) {
+            return;
+        }
+        if (schema.getDiscriminator() != null) {
+            return; // Duplicate oneOf are allowed if there is a discriminator that can be used to separate them.
+        }
+
+        Set<Schema> deduplicated = new LinkedHashSet<>(schema.getOneOf());
+        schema.setOneOf(new ArrayList<>(deduplicated));
+    }
+
     /**
      * Check if the schema is of type 'null' or schema itself is pointing to null
      * <p>

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

@@ -1107,3 +1107,16 @@ components:
           allOf:
             - $ref: '#/components/schemas/existing_tags_array'
             - description: This is a test for allOf with metadata only fields
+    DuplicateOneOf:
+      type: object
+      oneOf:
+        - $ref: '#/components/schemas/Order'
+        - $ref: '#/components/schemas/Order'
+    WithInnerOneOf:
+      type: object
+      properties:
+        foo:
+          type: object
+          oneOf:
+            - $ref: '#/components/schemas/Order'
+            - $ref: '#/components/schemas/Order'

samples/client/petstore/rust/hyper/petstore/.openapi-generator/FILES

@@ -8,6 +8,7 @@ docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
 docs/Category.md
+docs/DuplicateOneOf.md
 docs/DuplicateTest.md
 docs/Duplicatetest.md
 docs/EnumArrayTesting.md
@@ -32,6 +33,8 @@ docs/UniqueItemArrayTesting.md
 docs/User.md
 docs/UserApi.md
 docs/Vehicle.md
+docs/WithInnerOneOf.md
+docs/WithInnerOneOfFoo.md
 git_push.sh
 src/apis/client.rs
 src/apis/configuration.rs
@@ -50,6 +53,7 @@ src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
 src/models/category.rs
+src/models/duplicate_one_of.rs
 src/models/duplicate_test.rs
 src/models/duplicatetest.rs
 src/models/enum_array_testing.rs
@@ -69,3 +73,5 @@ src/models/type_testing.rs
 src/models/unique_item_array_testing.rs
 src/models/user.rs
 src/models/vehicle.rs
+src/models/with_inner_one_of.rs
+src/models/with_inner_one_of_foo.rs

samples/client/petstore/rust/hyper/petstore/README.md

@@ -61,6 +61,7 @@ Class | Method | HTTP request | Description
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
  - [Category](docs/Category.md)
+ - [DuplicateOneOf](docs/DuplicateOneOf.md)
  - [DuplicateTest](docs/DuplicateTest.md)
  - [Duplicatetest](docs/Duplicatetest.md)
  - [EnumArrayTesting](docs/EnumArrayTesting.md)
@@ -80,6 +81,8 @@ Class | Method | HTTP request | Description
  - [UniqueItemArrayTesting](docs/UniqueItemArrayTesting.md)
  - [User](docs/User.md)
  - [Vehicle](docs/Vehicle.md)
+ - [WithInnerOneOf](docs/WithInnerOneOf.md)
+ - [WithInnerOneOfFoo](docs/WithInnerOneOfFoo.md)
 
 
 To get access to the crate's generated documentation, use:

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

@@ -0,0 +1,11 @@
+# DuplicateOneOf
+
+## Enum Variants
+
+| Name | Description |
+|---- | -----|
+| Order |  |
+
+[[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/docs/WithInnerOneOf.md

@@ -0,0 +1,11 @@
+# WithInnerOneOf
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**models::WithInnerOneOfFoo**](WithInnerOneOf_foo.md)> |  | [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/docs/WithInnerOneOfFoo.md

@@ -0,0 +1,11 @@
+# WithInnerOneOfFoo
+
+## Enum Variants
+
+| Name | Description |
+|---- | -----|
+| Order |  |
+
+[[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/duplicate_one_of.rs

@@ -0,0 +1,41 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum DuplicateOneOf {
+    Order(Box<models::Order>),
+}
+
+impl Default for DuplicateOneOf {
+    fn default() -> Self {
+        Self::Order(Default::default())
+    }
+}
+/// Order Status
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
+pub enum Status {
+    #[serde(rename = "placed")]
+    Placed,
+    #[serde(rename = "approved")]
+    Approved,
+    #[serde(rename = "delivered")]
+    Delivered,
+}
+
+impl Default for Status {
+    fn default() -> Status {
+        Self::Placed
+    }
+}
+

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

@@ -10,6 +10,8 @@ pub mod baz;
 pub use self::baz::Baz;
 pub mod category;
 pub use self::category::Category;
+pub mod duplicate_one_of;
+pub use self::duplicate_one_of::DuplicateOneOf;
 pub mod duplicate_test;
 pub use self::duplicate_test::DuplicateTest;
 pub mod duplicatetest;
@@ -48,6 +50,10 @@ pub mod user;
 pub use self::user::User;
 pub mod vehicle;
 pub use self::vehicle::Vehicle;
+pub mod with_inner_one_of;
+pub use self::with_inner_one_of::WithInnerOneOf;
+pub mod with_inner_one_of_foo;
+pub use self::with_inner_one_of_foo::WithInnerOneOfFoo;
 use serde::{Deserialize, Deserializer, Serializer};
 use serde_with::{de::DeserializeAsWrap, ser::SerializeAsWrap, DeserializeAs, SerializeAs};
 use std::marker::PhantomData;

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

@@ -0,0 +1,27 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct WithInnerOneOf {
+    #[serde(rename = "foo", skip_serializing_if = "Option::is_none")]
+    pub foo: Option<Box<models::WithInnerOneOfFoo>>,
+}
+
+impl WithInnerOneOf {
+    pub fn new() -> WithInnerOneOf {
+        WithInnerOneOf {
+            foo: None,
+        }
+    }
+}
+

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

@@ -0,0 +1,41 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum WithInnerOneOfFoo {
+    Order(Box<models::Order>),
+}
+
+impl Default for WithInnerOneOfFoo {
+    fn default() -> Self {
+        Self::Order(Default::default())
+    }
+}
+/// Order Status
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
+pub enum Status {
+    #[serde(rename = "placed")]
+    Placed,
+    #[serde(rename = "approved")]
+    Approved,
+    #[serde(rename = "delivered")]
+    Delivered,
+}
+
+impl Default for Status {
+    fn default() -> Status {
+        Self::Placed
+    }
+}
+

samples/client/petstore/rust/hyper0x/petstore/.openapi-generator/FILES

@@ -8,6 +8,7 @@ docs/ApiResponse.md
 docs/ArrayItemRefTest.md
 docs/Baz.md
 docs/Category.md
+docs/DuplicateOneOf.md
 docs/DuplicateTest.md
 docs/Duplicatetest.md
 docs/EnumArrayTesting.md
@@ -32,6 +33,8 @@ docs/UniqueItemArrayTesting.md
 docs/User.md
 docs/UserApi.md
 docs/Vehicle.md
+docs/WithInnerOneOf.md
+docs/WithInnerOneOfFoo.md
 git_push.sh
 src/apis/configuration.rs
 src/apis/fake_api.rs
@@ -48,6 +51,7 @@ src/models/api_response.rs
 src/models/array_item_ref_test.rs
 src/models/baz.rs
 src/models/category.rs
+src/models/duplicate_one_of.rs
 src/models/duplicate_test.rs
 src/models/duplicatetest.rs
 src/models/enum_array_testing.rs
@@ -67,3 +71,5 @@ src/models/type_testing.rs
 src/models/unique_item_array_testing.rs
 src/models/user.rs
 src/models/vehicle.rs
+src/models/with_inner_one_of.rs
+src/models/with_inner_one_of_foo.rs

samples/client/petstore/rust/hyper0x/petstore/README.md

@@ -61,6 +61,7 @@ Class | Method | HTTP request | Description
  - [ArrayItemRefTest](docs/ArrayItemRefTest.md)
  - [Baz](docs/Baz.md)
  - [Category](docs/Category.md)
+ - [DuplicateOneOf](docs/DuplicateOneOf.md)
  - [DuplicateTest](docs/DuplicateTest.md)
  - [Duplicatetest](docs/Duplicatetest.md)
  - [EnumArrayTesting](docs/EnumArrayTesting.md)
@@ -80,6 +81,8 @@ Class | Method | HTTP request | Description
  - [UniqueItemArrayTesting](docs/UniqueItemArrayTesting.md)
  - [User](docs/User.md)
  - [Vehicle](docs/Vehicle.md)
+ - [WithInnerOneOf](docs/WithInnerOneOf.md)
+ - [WithInnerOneOfFoo](docs/WithInnerOneOfFoo.md)
 
 
 To get access to the crate's generated documentation, use:

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

@@ -0,0 +1,11 @@
+# DuplicateOneOf
+
+## Enum Variants
+
+| Name | Description |
+|---- | -----|
+| Order |  |
+
+[[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/docs/WithInnerOneOf.md

@@ -0,0 +1,11 @@
+# WithInnerOneOf
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**foo** | Option<[**models::WithInnerOneOfFoo**](WithInnerOneOf_foo.md)> |  | [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/docs/WithInnerOneOfFoo.md

@@ -0,0 +1,11 @@
+# WithInnerOneOfFoo
+
+## Enum Variants
+
+| Name | Description |
+|---- | -----|
+| Order |  |
+
+[[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/duplicate_one_of.rs

@@ -0,0 +1,41 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum DuplicateOneOf {
+    Order(Box<models::Order>),
+}
+
+impl Default for DuplicateOneOf {
+    fn default() -> Self {
+        Self::Order(Default::default())
+    }
+}
+/// Order Status
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
+pub enum Status {
+    #[serde(rename = "placed")]
+    Placed,
+    #[serde(rename = "approved")]
+    Approved,
+    #[serde(rename = "delivered")]
+    Delivered,
+}
+
+impl Default for Status {
+    fn default() -> Status {
+        Self::Placed
+    }
+}
+