[rust] Fixed discriminator causing duplicate enum variants (#20711)

* Fixed discriminator

* Added testcase and updated samples

Author: ranger-ross

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

@@ -22,15 +22,18 @@
 import java.io.Writer;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.EnumSet;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 import org.openapitools.codegen.CliOption;
@@ -342,6 +345,32 @@ public ModelsMap postProcessModels(ModelsMap objs) {
                         break;
                     }
                 }
+
+                // Check if there are duplicate mappings in the discriminator
+                // ie.
+                // ```
+                // mappings:
+                //   student: '#/components/schemas/Person'
+                //   teacher: '#/components/schemas/Person'
+                //   car: '#/components/schemas/Vehicle'
+                // ```
+                //
+                // Should be mapped to an enum with `PersonStudent`, `PersonTeacher`, `Vehicle` to 2 `Person` enum variants. (a compiler error)
+                if (cm.discriminator.getMapping() != null) {
+                    if (hasDuplicateValues(cm.discriminator.getMapping())) {
+                        var inverted = invertMap(cm.discriminator.getMapping());
+                        for (var s : inverted.entrySet()) {
+                            if (s.getValue().size() > 1) {
+                                LOGGER.debug("Found duplicated enum model (" + s.getKey() + ") in model " + cm.name + ". Adding suffix to model names.");
+                                for (var m : cm.discriminator.getMappedModels()) {
+                                    if (s.getValue().contains(m.getMappingName())) {
+                                        m.setModelName(m.getModelName() + StringUtils.camelize(m.getMappingName()));
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
             }
 
             // Flag structs with byteArrays in them so that we can annotate them with the serde_as macro
@@ -789,4 +818,18 @@ protected ImmutableMap.Builder<String, Lambda> addMustacheLambdas() {
                 .put("lifetimeName", new ReplaceAllLambda("^r#", "r_"));
     }
 
+    public static <K, V> Map<V, List<K>> invertMap(Map<K, V> map) {
+        Map<V, List<K>> invertedMap = new HashMap<>();
+
+        for (Map.Entry<K, V> entry : map.entrySet()) {
+            invertedMap.computeIfAbsent(entry.getValue(), k -> new ArrayList<>()).add(entry.getKey());
+        }
+
+        return invertedMap;
+    }
+
+    public static <K, V> boolean hasDuplicateValues(Map<K, V> map) {
+        Set<V> uniqueValues = new HashSet<>(map.values());
+        return uniqueValues.size() < map.size();
+    }
 }

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

@@ -656,6 +656,26 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/TypeTesting'
+  '/tests/discriminatorDuplicateEnums':
+    get:
+      tags:
+        - testing
+      summary: 'Test for duplicate enums when using discriminator. (One of the issues in #20500)'
+      responses:
+        '200':
+          description: test
+          content:
+            application/json:
+              schema:
+                anyOf:
+                  - $ref: '#/components/schemas/Person'
+                  - $ref: '#/components/schemas/Vehicle'
+                discriminator:
+                  propertyName: objectType
+                  mapping:
+                    student: '#/components/schemas/Person'
+                    teacher: '#/components/schemas/Person'
+                    car: '#/components/schemas/Vehicle'
 externalDocs:
   description: Find out more about Swagger
   url: 'http://swagger.io'
@@ -1014,4 +1034,24 @@ components:
       properties:
         foo: {}
       required: ["foo"]
+    Person:
+      type: object
+      properties:
+        type:
+          type: string
+        name:
+          type: string
+      required:
+       - type
+       - name
+    Vehicle:
+      type: object
+      properties:
+        type:
+          type: string
+        speed:
+          type: number
+      required:
+       - type
+       - speed
 

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

@@ -14,6 +14,7 @@ docs/NullableArray.md
 docs/NumericEnumTesting.md
 docs/OptionalTesting.md
 docs/Order.md
+docs/Person.md
 docs/Pet.md
 docs/PetApi.md
 docs/PropertyTest.md
@@ -22,10 +23,12 @@ docs/Return.md
 docs/StoreApi.md
 docs/Tag.md
 docs/TestingApi.md
+docs/TestsDiscriminatorDuplicateEnumsGet200Response.md
 docs/TypeTesting.md
 docs/UniqueItemArrayTesting.md
 docs/User.md
 docs/UserApi.md
+docs/Vehicle.md
 git_push.sh
 src/apis/client.rs
 src/apis/configuration.rs
@@ -37,6 +40,7 @@ src/apis/store_api.rs
 src/apis/testing_api.rs
 src/apis/user_api.rs
 src/lib.rs
+src/models/_tests_discriminator_duplicate_enums_get_200_response.rs
 src/models/action_container.rs
 src/models/any_type_test.rs
 src/models/api_response.rs
@@ -51,9 +55,11 @@ src/models/nullable_array.rs
 src/models/numeric_enum_testing.rs
 src/models/optional_testing.rs
 src/models/order.rs
+src/models/person.rs
 src/models/pet.rs
 src/models/property_test.rs
 src/models/tag.rs
 src/models/type_testing.rs
 src/models/unique_item_array_testing.rs
 src/models/user.rs
+src/models/vehicle.rs

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

@@ -39,6 +39,7 @@ Class | Method | HTTP request | Description
 *StoreApi* | [**get_inventory**](docs/StoreApi.md#get_inventory) | **Get** /store/inventory | Returns pet inventories by status
 *StoreApi* | [**get_order_by_id**](docs/StoreApi.md#get_order_by_id) | **Get** /store/order/{orderId} | Find purchase order by ID
 *StoreApi* | [**place_order**](docs/StoreApi.md#place_order) | **Post** /store/order | Place an order for a pet
+*TestingApi* | [**tests_discriminator_duplicate_enums_get**](docs/TestingApi.md#tests_discriminator_duplicate_enums_get) | **Get** /tests/discriminatorDuplicateEnums | Test for duplicate enums when using discriminator. (One of the issues in #20500)
 *TestingApi* | [**tests_file_response_get**](docs/TestingApi.md#tests_file_response_get) | **Get** /tests/fileResponse | Returns an image file
 *TestingApi* | [**tests_type_testing_get**](docs/TestingApi.md#tests_type_testing_get) | **Get** /tests/typeTesting | Route to test the TypeTesting schema
 *UserApi* | [**create_user**](docs/UserApi.md#create_user) | **Post** /user | Create user
@@ -64,14 +65,17 @@ Class | Method | HTTP request | Description
  - [NumericEnumTesting](docs/NumericEnumTesting.md)
  - [OptionalTesting](docs/OptionalTesting.md)
  - [Order](docs/Order.md)
+ - [Person](docs/Person.md)
  - [Pet](docs/Pet.md)
  - [PropertyTest](docs/PropertyTest.md)
  - [Ref](docs/Ref.md)
  - [Return](docs/Return.md)
  - [Tag](docs/Tag.md)
+ - [TestsDiscriminatorDuplicateEnumsGet200Response](docs/TestsDiscriminatorDuplicateEnumsGet200Response.md)
  - [TypeTesting](docs/TypeTesting.md)
  - [UniqueItemArrayTesting](docs/UniqueItemArrayTesting.md)
  - [User](docs/User.md)
+ - [Vehicle](docs/Vehicle.md)
 
 
 To get access to the crate's generated documentation, use:

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

@@ -0,0 +1,12 @@
+# Person
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**r#type** | **String** |  | 
+**name** | **String** |  | 
+
+[[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/TestingApi.md

@@ -4,11 +4,37 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
+[**tests_discriminator_duplicate_enums_get**](TestingApi.md#tests_discriminator_duplicate_enums_get) | **Get** /tests/discriminatorDuplicateEnums | Test for duplicate enums when using discriminator. (One of the issues in #20500)
 [**tests_file_response_get**](TestingApi.md#tests_file_response_get) | **Get** /tests/fileResponse | Returns an image file
 [**tests_type_testing_get**](TestingApi.md#tests_type_testing_get) | **Get** /tests/typeTesting | Route to test the TypeTesting schema
 
 
 
+## tests_discriminator_duplicate_enums_get
+
+> models::TestsDiscriminatorDuplicateEnumsGet200Response tests_discriminator_duplicate_enums_get()
+Test for duplicate enums when using discriminator. (One of the issues in #20500)
+
+### Parameters
+
+This endpoint does not need any parameter.
+
+### Return type
+
+[**models::TestsDiscriminatorDuplicateEnumsGet200Response**](_tests_discriminatorDuplicateEnums_get_200_response.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
+
 ## tests_file_response_get
 
 > std::path::PathBuf tests_file_response_get()

samples/client/petstore/rust/hyper/petstore/docs/TestsDiscriminatorDuplicateEnumsGet200Response.md

@@ -0,0 +1,10 @@
+# TestsDiscriminatorDuplicateEnumsGet200Response
+
+## Enum Variants
+
+| Name | Value |
+|---- | -----|
+
+[[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/Vehicle.md

@@ -0,0 +1,12 @@
+# Vehicle
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**r#type** | **String** |  | 
+**speed** | **f64** |  | 
+
+[[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/apis/testing_api.rs

@@ -37,12 +37,21 @@ impl<C: Connect> TestingApiClient<C>
 }
 
 pub trait TestingApi: Send + Sync {
+    fn tests_discriminator_duplicate_enums_get(&self, ) -> Pin<Box<dyn Future<Output = Result<models::TestsDiscriminatorDuplicateEnumsGet200Response, Error>> + Send>>;
     fn tests_file_response_get(&self, ) -> Pin<Box<dyn Future<Output = Result<std::path::PathBuf, Error>> + Send>>;
     fn tests_type_testing_get(&self, ) -> Pin<Box<dyn Future<Output = Result<models::TypeTesting, Error>> + Send>>;
 }
 
 impl<C: Connect>TestingApi for TestingApiClient<C>
     where C: Clone + std::marker::Send + Sync {
+    #[allow(unused_mut)]
+    fn tests_discriminator_duplicate_enums_get(&self, ) -> Pin<Box<dyn Future<Output = Result<models::TestsDiscriminatorDuplicateEnumsGet200Response, Error>> + Send>> {
+        let mut req = __internal_request::Request::new(hyper::Method::GET, "/tests/discriminatorDuplicateEnums".to_string())
+        ;
+
+        req.execute(self.configuration.borrow())
+    }
+
     #[allow(unused_mut)]
     fn tests_file_response_get(&self, ) -> Pin<Box<dyn Future<Output = Result<std::path::PathBuf, Error>> + Send>> {
         let mut req = __internal_request::Request::new(hyper::Method::GET, "/tests/fileResponse".to_string())

samples/client/petstore/rust/hyper/petstore/src/models/_tests_discriminator_duplicate_enums_get_200_response.rs

@@ -0,0 +1,57 @@
+/*
+ * 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(tag = "objectType")]
+pub enum TestsDiscriminatorDuplicateEnumsGet200Response {
+    #[serde(rename="car")]
+    Vehicle {
+        #[serde(rename = "type")]
+        r#type: String,
+        #[serde(rename = "name")]
+        name: String,
+        #[serde(rename = "speed")]
+        speed: f64,
+    },
+    #[serde(rename="student")]
+    PersonStudent {
+        #[serde(rename = "type")]
+        r#type: String,
+        #[serde(rename = "name")]
+        name: String,
+        #[serde(rename = "speed")]
+        speed: f64,
+    },
+    #[serde(rename="teacher")]
+    PersonTeacher {
+        #[serde(rename = "type")]
+        r#type: String,
+        #[serde(rename = "name")]
+        name: String,
+        #[serde(rename = "speed")]
+        speed: f64,
+    },
+}
+
+impl Default for TestsDiscriminatorDuplicateEnumsGet200Response {
+    fn default() -> Self {
+        Self::Vehicle {
+            r#type: Default::default(),
+            name: Default::default(),
+            speed: Default::default(),
+        }
+        
+    }
+}
+
+