[Protobuf] Fix Discriminator Issue and add capability Enum Extraction

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

@@ -88,6 +88,10 @@ public MappedModel(String mappingName, String modelName, boolean explicitMapping
             this.explicitMapping = explicitMapping;
         }
 
+        public boolean isExplicitMapping() {
+            return explicitMapping;
+        }
+
         public MappedModel(String mappingName, String modelName) {
             this(mappingName, modelName, false);
         }

modules/openapi-generator/src/main/resources/protobuf-schema/enum.mustache

@@ -1,7 +1,26 @@
-enum {{classname}} {
-  {{#allowableValues}}
-  {{#enumVars}}
-  {{{name}}} = {{{protobuf-enum-index}}};
-  {{/enumVars}}
-  {{/allowableValues}}
+{{!
+  Generates an extracted enum wrapped in a message container.
+
+  This wrapper pattern is used to prevent enum value name collisions
+  in the Protocol Buffers global enum namespace. Multiple enums can
+  have values with the same name when wrapped in separate messages.
+
+  Generated format:
+    message EnumName {
+      enum Enum {
+        VALUE1 = 0;
+        VALUE2 = 1;
+      }
+    }
+
+  Usage in models: EnumName.Enum field_name = 1;
+}}
+message {{classname}} {
+  enum Enum {
+    {{#allowableValues}}
+    {{#enumVars}}
+    {{{name}}} = {{{protobuf-enum-index}}};
+    {{/enumVars}}
+    {{/allowableValues}}
+  }
 }

modules/openapi-generator/src/main/resources/protobuf-schema/model.mustache

@@ -37,6 +37,7 @@ import public "{{{.}}}.proto";
   {{#vendorExtensions.x-protobuf-type}}{{{.}}} {{/vendorExtensions.x-protobuf-type}}{{{vendorExtensions.x-protobuf-data-type}}} {{{name}}} = {{vendorExtensions.x-protobuf-index}}{{#vendorExtensions.x-protobuf-packed}} [packed=true]{{/vendorExtensions.x-protobuf-packed}}{{#vendorExtensions.x-protobuf-json-name}} [json_name="{{vendorExtensions.x-protobuf-json-name}}"]{{/vendorExtensions.x-protobuf-json-name}};
   {{/isEnum}}
   {{#isEnum}}
+  {{^vendorExtensions.x-protobuf-enum-reference-import}}
   enum {{enumName}} {
     {{#allowableValues}}
     {{#enumVars}}
@@ -45,7 +46,8 @@ import public "{{{.}}}.proto";
     {{/allowableValues}}
   }
 
-  {{enumName}} {{name}} = {{vendorExtensions.x-protobuf-index}};
+  {{/vendorExtensions.x-protobuf-enum-reference-import}}
+  {{#vendorExtensions.x-protobuf-type}}{{{.}}} {{/vendorExtensions.x-protobuf-type}}{{{vendorExtensions.x-protobuf-data-type}}} {{name}} = {{vendorExtensions.x-protobuf-index}};
   {{/isEnum}}
 
   {{/vars}}

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

@@ -48,6 +48,8 @@ components:
           properties:
             name:
               type: string
+            characteristics:
+              $ref: '#/components/schemas/Characteristics'
     Reptile:
       allOf:
         - $ref: '#/components/schemas/Pet'
@@ -78,7 +80,7 @@ components:
         - $ref: '#/components/schemas/Lizard'
       discriminator:
         propertyName: petType
-        # per https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#discriminatorObject
+        # per https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#discriminator-object
         # this discriminator must be included to use it as a hint to pick a schema
     MyPetsNoDisc:
       oneOf:
@@ -101,3 +103,8 @@ components:
     C:
       allOf:
         - $ref: '#/components/schemas/B'
+    Characteristics:
+      type: object
+      properties:
+        canHunt:
+          type: boolean

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

@@ -0,0 +1,58 @@
+openapi: 3.0.3
+info:
+  title: OAI Specification example for Polymorphism
+  version: 1.0.0
+paths:
+  /status:
+    get:
+      responses:
+        '201':
+          description: desc
+
+components:
+  schemas:
+    Animal:
+      type: object
+      required:
+        - petType
+      properties:
+        petType:
+          type: string
+      discriminator:
+        propertyName: petType
+        mapping:
+          dog: '#/components/schemas/Dog'
+          cat: '#/components/schemas/Cat'
+    Feline:
+      allOf:
+        - $ref: '#/components/schemas/Animal'
+        - type: object
+          properties:
+            name:
+              type: string
+            furColor:
+              type: string
+    Cat:
+      allOf:
+        - $ref: '#/components/schemas/Feline'
+        - type: object
+          properties:
+            isIndoor:
+              type: boolean
+            careDetails:
+              $ref: '#/components/schemas/CareDetails'
+    Dog:
+      allOf:
+        - $ref: '#/components/schemas/Animal'
+        - type: object
+          properties:
+            bark:
+              type: string
+    CareDetails:
+      type: object
+      properties:
+        veterinarian:
+          type: string
+        lastVetVisit:
+          type: string
+          format: date

modules/openapi-generator/src/test/resources/3_0/protobuf-schema/animal.proto

@@ -0,0 +1,31 @@
+/*
+  OAI Specification example for Polymorphism
+
+  No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+
+  The version of the OpenAPI document: 1.0.0
+
+  Generated by OpenAPI Generator: https://openapi-generator.tech
+*/
+
+syntax = "proto3";
+
+package openapitools;
+
+import public "models/care_details.proto";
+
+message Animal {
+
+  string pet_type = 482112090;
+
+  string name = 3373707;
+
+  string fur_color = 478695002;
+
+  bool is_indoor = 183319801;
+
+  CareDetails care_details = 176721135;
+
+  string bark = 3016376;
+
+}

modules/openapi-generator/src/test/resources/3_0/protobuf-schema/extracted_enum.yaml

@@ -0,0 +1,77 @@
+openapi: 3.0.0
+info:
+  title: Enum extraction test
+  version: '2.0'
+paths: {}
+components:
+  schemas:
+    SeparatedEnum:
+      type: string
+      enum:
+        - VALUE1
+        - VALUE2
+    ModelWithEnums:
+      type: object
+      properties:
+        referenceEnumProperty:
+          $ref: "#/components/schemas/SeparatedEnum"
+        inlineEnumProperty:
+          type: string
+          enum:
+            - VALUE2
+            - VALUE3
+            - VALUE4
+        listOfEnums:
+          type: array
+          items:
+            type: string
+            enum:
+              - VALUE10
+              - VALUE11
+    AllOfModelWithEnums:
+      allOf:
+        - $ref: "#/components/schemas/ModelWithEnums"
+        - type: object
+          properties:
+            anotherInlineEnumProperty:
+              type: string
+              enum:
+                - VALUE5
+                - VALUE6
+            listOfReferencedEnums:
+              type: array
+              items:
+                $ref: '#/components/schemas/SeparatedEnum'
+    DiscriminatedModel:
+      type: object
+      properties:
+        commonProperty:
+          type: string
+        modelType:
+          type: string
+      discriminator:
+        propertyName: modelType
+        mapping:
+          typeA: "#/components/schemas/ModelTypeAWithInlineEnum"
+          typeB: "#/components/schemas/ModelTypeBWithInlineEnum"
+    ModelTypeAWithInlineEnum:
+      allOf: 
+        -  $ref: "#/components/schemas/DiscriminatedModel"
+        - type: object
+          properties:
+            specificPropertyA:
+              type: string
+            inlineEnumProperty:
+              type: string
+              enum:
+                - VALUE7
+                - VALUE8
+    ModelTypeBWithInlineEnum:
+      allOf: 
+        -  $ref: "#/components/schemas/DiscriminatedModel"
+        - type: object
+          properties:
+            specificPropertyB:
+              type: string
+            referenceEnumPropertyB:
+              $ref: "#/components/schemas/SeparatedEnum"

modules/openapi-generator/src/test/resources/3_0/protobuf-schema/model_imported_once.yaml

@@ -0,0 +1,89 @@
+openapi: 3.0.0
+info:
+  title: Model Import Test
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    A:
+      type: object
+      description: Base model A that will be referenced multiple times
+      properties:
+        id:
+          type: string
+        value:
+          type: string
+      required:
+        - id
+
+    SubModel:
+      type: object
+      description: SubModel that uses model A
+      allOf:
+        - $ref: '#/components/schemas/ExtensibleModel'
+        - type: object
+          properties:
+            subField:
+              type: string
+            aReference:
+              $ref: '#/components/schemas/A'
+          required:
+            - subField
+
+    Model:
+      type: object
+      description: Main model that uses A directly and via SubModel
+      properties:
+        name:
+          type: string
+        directA:
+          $ref: '#/components/schemas/A'
+        nestedSubModel:
+          $ref: '#/components/schemas/SubModel'
+      required:
+        - name
+
+    ExtensibleModel:
+      type: object
+      description: Extensible model with discriminator that uses model A
+      discriminator:
+        propertyName: type
+        mapping:
+          child1: '#/components/schemas/ChildModel_1'
+          child2: '#/components/schemas/ChildModel_2'
+      properties:
+        type:
+          type: string
+        extensibleA:
+          $ref: '#/components/schemas/A'
+      required:
+        - type
+
+    ChildModel_1:
+      allOf:
+        - $ref: '#/components/schemas/ExtensibleModel'
+        - type: object
+          properties:
+            childSpecificField:
+              type: string
+            childA:
+              $ref: '#/components/schemas/A'
+    ChildModel_2:
+      allOf:
+        - $ref: '#/components/schemas/SubExtensibleModel'
+        - type: object
+          properties:
+            anotherChildSpecificField:
+              type: integer
+            directA:
+              $ref: '#/components/schemas/A'
+
+    SubExtensibleModel:
+      allOf:
+        - $ref: '#/components/schemas/ExtensibleModel'
+        - type: object
+          properties:
+            aSubExtensibleField:
+              type: boolean
+            subDirectA:
+              $ref: '#/components/schemas/A'

modules/openapi-generator/src/test/resources/3_0/protobuf-schema/pet.proto

@@ -12,14 +12,20 @@ syntax = "proto3";
 
 package openapitools;
 
+import public "models/characteristics.proto";
+
 message Pet {
 
   string pet_type = 482112090;
 
   string name = 3373707;
 
+  Characteristics characteristics = 455429578;
+
   string bark = 3016376;
 
   bool loves_rocks = 465093427;
 
+  bool has_legs = 140596906;
+
 }