[BUG] The Field name is Duplicated when use `modelNamePrefix: Api` or `modelNameSuffix: Api` in go

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• [ x ] Have you provided a full/minimal spec to reproduce the issue?
• [ x ] Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• [ x ] What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

The struct name is Duplicated when use modelNamePrefix: Api or modelNameSuffix: Api.

When the code is generated, the struct ApiTag name is ok.

In api_model_pet.go , the struct ApiPet has a field is Tags []ApiApiTag json:"tags,omitempty".

ApiApiTag is modelNamePrefix duplicated. Its name should be ApiTag.

openapi-generator version

7.14.0 open-generator-cli

OpenAPI declaration file content or url

petstore-api.yaml

openapi: 3.0.0
info:
  contact:
    email: support@petstore.com
    name: API Support
    url: https://petstore.com/support
  description: |
    A sample API that demonstrates OpenAPI 3.1 features including:
    - CRUD operations for pets
    - File upload for pet avatars
    - Advanced validation and examples
    - Webhooks support
  license:
    name: MIT
    url: https://opensource.org/licenses/MIT
  title: Petstore API
  version: 1.0.0
servers:
- description: Production server
  url: https://api.petstore.com/v1
- description: Staging server
  url: https://staging-api.petstore.com/v1
- description: Local development server
  url: http://localhost:8080/v1
security:
- petstore_auth:
  - read:pets
  - write:pets
- api_key: []
tags:
- description: Pet management operations
  name: pets
- description: File upload operations
  name: upload
paths:
  /pets:
    get:
      description: Retrieve a list of all pets with optional filtering and pagination
      operationId: listPets
      parameters:
      - description: Maximum number of pets to return
        explode: true
        in: query
        name: limit
        required: false
        schema:
          default: 20
          maximum: 100
          minimum: 1
          type: integer
        style: form
      - description: Number of pets to skip for pagination
        explode: true
        in: query
        name: offset
        required: false
        schema:
          default: 0
          minimum: 0
          type: integer
        style: form
      - description: Filter pets by status
        explode: true
        in: query
        name: status
        required: false
        schema:
          enum:
          - available
          - pending
          - sold
          type: string
        style: form
      - description: Filter pets by category
        explode: true
        in: query
        name: category
        required: false
        schema:
          type: string
        style: form
      responses:
        "200":
          content:
            application/json:
              examples:
                success:
                  summary: Successful response
                  value:
                    pets:
                    - id: 1
                      name: Fluffy
                      category: cat
                      status: available
                      tags:
                      - name: friendly
                      - name: playful
                      photoUrls:
                      - https://example.com/fluffy.jpg
                    - id: 2
                      name: Buddy
                      category: dog
                      status: available
                      tags:
                      - name: loyal
                      photoUrls:
                      - https://example.com/buddy.jpg
                    total: 2
                    limit: 20
                    offset: 0
              schema:
                $ref: "#/components/schemas/listPets_200_response"
          description: A list of pets
        "400":
          $ref: "#/components/responses/BadRequest"
        "401":
          $ref: "#/components/responses/Unauthorized"
        "500":
          $ref: "#/components/responses/InternalServerError"
      summary: List all pets
      tags:
      - pets
    post:
      description: Add a new pet to the store
      operationId: createPet
      requestBody:
        content:
          application/json:
            examples:
              cat:
                summary: Create a cat
                value:
                  name: Whiskers
                  category: cat
                  status: available
                  tags:
                  - name: independent
                  - name: clean
                  photoUrls:
                  - https://example.com/whiskers.jpg
              dog:
                summary: Create a dog
                value:
                  name: Max
                  category: dog
                  status: available
                  tags:
                  - name: energetic
                  - name: friendly
                  photoUrls:
                  - https://example.com/max.jpg
            schema:
              $ref: "#/components/schemas/PetInput"
        required: true
      responses:
        "201":
          content:
            application/json:
              examples:
                created:
                  summary: Pet created
                  value:
                    id: 123
                    name: Whiskers
                    category: cat
                    status: available
                    tags:
                    - name: independent
                    - name: clean
                    photoUrls:
                    - https://example.com/whiskers.jpg
                    createdAt: 2024-01-15T10:30:00Z
                    updatedAt: 2024-01-15T10:30:00Z
              schema:
                $ref: "#/components/schemas/Pet"
          description: Pet created successfully
        "400":
          $ref: "#/components/responses/BadRequest"
        "401":
          $ref: "#/components/responses/Unauthorized"
        "422":
          $ref: "#/components/responses/ValidationError"
      summary: Create a new pet
      tags:
      - pets
  /pets/{petId}:
    delete:
      description: Remove a pet from the store
      operationId: deletePet
      parameters:
      - description: ID of the pet to retrieve
        examples:
          valid_id:
            summary: Valid pet ID
            value: 123
          invalid_id:
            summary: Invalid pet ID
            value: -1
        explode: false
        in: path
        name: petId
        required: true
        schema:
          minimum: 1
          type: integer
        style: simple
      responses:
        "204":
          description: Pet deleted successfully
        "404":
          $ref: "#/components/responses/NotFound"
        "500":
          $ref: "#/components/responses/InternalServerError"
      summary: Delete pet
      tags:
      - pets
    get:
      description: Retrieve a specific pet by its ID
      operationId: getPetById
      parameters:
      - description: ID of the pet to retrieve
        examples:
          valid_id:
            summary: Valid pet ID
            value: 123
          invalid_id:
            summary: Invalid pet ID
            value: -1
        explode: false
        in: path
        name: petId
        required: true
        schema:
          minimum: 1
          type: integer
        style: simple
      responses:
        "200":
          content:
            application/json:
              examples:
                cat:
                  summary: Cat pet
                  value:
                    id: 1
                    name: Fluffy
                    category: cat
                    status: available
                    tags:
                    - name: friendly
                    - name: playful
                    photoUrls:
                    - https://example.com/fluffy.jpg
                    createdAt: 2024-01-10T09:00:00Z
                    updatedAt: 2024-01-15T14:30:00Z
              schema:
                $ref: "#/components/schemas/Pet"
          description: Pet found
        "404":
          $ref: "#/components/responses/NotFound"
        "500":
          $ref: "#/components/responses/InternalServerError"
      summary: Get pet by ID
      tags:
      - pets
    put:
      description: Update an existing pet's information
      operationId: updatePet
      parameters:
      - description: ID of the pet to retrieve
        examples:
          valid_id:
            summary: Valid pet ID
            value: 123
          invalid_id:
            summary: Invalid pet ID
            value: -1
        explode: false
        in: path
        name: petId
        required: true
        schema:
          minimum: 1
          type: integer
        style: simple
      requestBody:
        content:
          application/json:
            examples:
              update:
                summary: Update pet information
                value:
                  name: Fluffy Updated
                  category: cat
                  status: sold
                  tags:
                  - name: friendly
                  - name: adopted
                  photoUrls:
                  - https://example.com/fluffy-updated.jpg
            schema:
              $ref: "#/components/schemas/PetInput"
        required: true
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pet"
          description: Pet updated successfully
        "400":
          $ref: "#/components/responses/BadRequest"
        "404":
          $ref: "#/components/responses/NotFound"
        "422":
          $ref: "#/components/responses/ValidationError"
      summary: Update pet
      tags:
      - pets
  /pets/{petId}/avatar:
    post:
      description: Upload an avatar image for a specific pet
      operationId: uploadPetAvatar
      parameters:
      - description: ID of the pet to upload avatar for
        explode: false
        in: path
        name: petId
        required: true
        schema:
          minimum: 1
          type: integer
        style: simple
      requestBody:
        content:
          multipart/form-data:
            encoding:
              file:
                contentType: "image/jpeg, image/png, image/gif, image/webp"
                style: form
            schema:
              $ref: "#/components/schemas/uploadPetAvatar_request"
        required: true
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/uploadPetAvatar_200_response"
          description: Avatar uploaded successfully
        "400":
          $ref: "#/components/responses/BadRequest"
        "404":
          $ref: "#/components/responses/NotFound"
        "413":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/uploadPetAvatar_413_response"
          description: File too large
        "415":
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/uploadPetAvatar_415_response"
          description: Unsupported media type
      summary: Upload pet avatar
      tags:
      - pets
      - upload
  /pets/findByStatus:
    get:
      description: Multiple status values can be provided with comma separated strings
      operationId: findPetsByStatus
      parameters:
      - description: Status values that need to be considered for filter
        explode: true
        in: query
        name: status
        required: true
        schema:
          items:
            enum:
            - available
            - pending
            - sold
            type: string
          type: array
        style: form
      responses:
        "200":
          content:
            application/json:
              schema:
                items:
                  $ref: "#/components/schemas/Pet"
                type: array
          description: Successful operation
        "400":
          $ref: "#/components/responses/BadRequest"
      summary: Find pets by status
      tags:
      - pets
components:
  responses:
    BadRequest:
      content:
        application/json:
          examples:
            invalid_input:
              summary: Invalid input
              value:
                code: 400
                message: Bad Request
                details:
                - field: name
                  message: Name is required
                - field: status
                  message: "Status must be one of: available, pending, sold"
          schema:
            $ref: "#/components/schemas/Error"
      description: Bad request
    Unauthorized:
      content:
        application/json:
          examples:
            no_auth:
              summary: No authentication
              value:
                code: 401
                message: Unauthorized - Authentication required
          schema:
            $ref: "#/components/schemas/Error"
      description: Unauthorized
    NotFound:
      content:
        application/json:
          examples:
            pet_not_found:
              summary: Pet not found
              value:
                code: 404
                message: Pet not found
          schema:
            $ref: "#/components/schemas/Error"
      description: Pet not found
    ValidationError:
      content:
        application/json:
          examples:
            validation_failed:
              summary: Validation failed
              value:
                code: 422
                message: Validation failed
                details:
                - field: name
                  message: Name must be between 1 and 100 characters
                - field: category
                  message: "Category must be one of: cat, dog, bird, fish, reptile,\
                    \ other"
          schema:
            $ref: "#/components/schemas/Error"
      description: Validation error
    InternalServerError:
      content:
        application/json:
          examples:
            server_error:
              summary: Server error
              value:
                code: 500
                message: Internal server error
          schema:
            $ref: "#/components/schemas/Error"
      description: Internal server error
  schemas:
    Pet:
      example:
        createdAt: 2024-01-10T09:00:00Z
        photoUrls:
        - https://example.com/fluffy.jpg
        name: Fluffy
        id: 123
        category: cat
        status: available
        tags:
        - name: friendly
          id: 1
        - name: friendly
          id: 1
        updatedAt: 2024-01-15T14:30:00Z
      properties:
        id:
          description: Unique identifier for the pet
          example: 123
          format: int64
          type: integer
        name:
          description: Pet's name
          example: Fluffy
          maxLength: 100
          minLength: 1
          type: string
        category:
          description: Pet category
          enum:
          - cat
          - dog
          - bird
          - fish
          - reptile
          - other
          example: cat
          type: string
        status:
          description: Pet status in the store
          enum:
          - available
          - pending
          - sold
          example: available
          type: string
        tags:
          description: Tags associated with the pet
          items:
            $ref: "#/components/schemas/Tag"
          type: array
        photoUrls:
          description: URLs of pet photos
          example:
          - https://example.com/fluffy.jpg
          items:
            format: uri
            type: string
          type: array
        createdAt:
          description: When the pet was created
          example: 2024-01-10T09:00:00Z
          format: date-time
          type: string
        updatedAt:
          description: When the pet was last updated
          example: 2024-01-15T14:30:00Z
          format: date-time
          type: string
      required:
      - name
      - status
      type: object
    PetInput:
      properties:
        name:
          description: Pet's name
          example: Fluffy
          maxLength: 100
          minLength: 1
          type: string
        category:
          description: Pet category
          enum:
          - cat
          - dog
          - bird
          - fish
          - reptile
          - other
          example: cat
          type: string
        status:
          description: Pet status in the store
          enum:
          - available
          - pending
          - sold
          example: available
          type: string
        tags:
          description: Tags associated with the pet
          items:
            $ref: "#/components/schemas/Tag"
          type: array
        photoUrls:
          description: URLs of pet photos
          example:
          - https://example.com/fluffy.jpg
          items:
            format: uri
            type: string
          type: array
      required:
      - name
      - status
      type: object
    Tag:
      example:
        name: friendly
        id: 1
      properties:
        id:
          description: Tag ID
          example: 1
          format: int64
          type: integer
        name:
          description: Tag name
          example: friendly
          maxLength: 50
          minLength: 1
          type: string
      type: object
    Error:
      example:
        code: 400
        details:
        - field: name
          message: Name is required
        - field: status
          message: "Status must be one of: available, pending, sold"
        message: Bad Request
      properties:
        code:
          description: Error code
          example: 400
          format: int32
          type: integer
        message:
          description: Error message
          example: Bad Request
          type: string
        details:
          description: Detailed error information
          example:
          - field: name
            message: Name is required
          - field: status
            message: "Status must be one of: available, pending, sold"
          items:
            $ref: "#/components/schemas/Error_details_inner"
          type: array
      required:
      - code
      - message
      type: object
    listPets_200_response:
      example:
        pets:
        - createdAt: 2024-01-10T09:00:00Z
          photoUrls:
          - https://example.com/fluffy.jpg
          name: Fluffy
          id: 123
          category: cat
          status: available
          tags:
          - name: friendly
            id: 1
          - name: friendly
            id: 1
          updatedAt: 2024-01-15T14:30:00Z
        - createdAt: 2024-01-10T09:00:00Z
          photoUrls:
          - https://example.com/fluffy.jpg
          name: Fluffy
          id: 123
          category: cat
          status: available
          tags:
          - name: friendly
            id: 1
          - name: friendly
            id: 1
          updatedAt: 2024-01-15T14:30:00Z
        total: 0
        offset: 1
        limit: 6
      properties:
        pets:
          items:
            $ref: "#/components/schemas/Pet"
          type: array
        total:
          description: Total number of pets
          type: integer
        limit:
          description: Number of pets returned
          type: integer
        offset:
          description: Number of pets skipped
          type: integer
      type: object
    uploadPetAvatar_request:
      properties:
        file:
          description: Pet avatar image file
          format: binary
          maxLength: 10485760
          type: string
        description:
          description: Optional description for the avatar
          maxLength: 500
          type: string
      required:
      - file
      type: object
    uploadPetAvatar_200_response:
      example:
        avatarUrl: https://example.com/avatars/pet-123-avatar.jpg
        fileSize: 245760
        uploadedAt: 2024-01-15T15:30:00Z
        message: Avatar uploaded successfully
      properties:
        message:
          example: Avatar uploaded successfully
          type: string
        avatarUrl:
          example: https://example.com/avatars/pet-123-avatar.jpg
          format: uri
          type: string
        fileSize:
          description: File size in bytes
          example: 245760
          type: integer
        uploadedAt:
          example: 2024-01-15T15:30:00Z
          format: date-time
          type: string
      type: object
    uploadPetAvatar_413_response:
      example:
        error: File size exceeds maximum limit of 10MB
      properties:
        error:
          example: File size exceeds maximum limit of 10MB
          type: string
      type: object
    uploadPetAvatar_415_response:
      example:
        error: "Unsupported file type. Please use JPEG, PNG, GIF, or WebP"
      properties:
        error:
          example: "Unsupported file type. Please use JPEG, PNG, GIF, or WebP"
          type: string
      type: object
    Error_details_inner:
      properties:
        field:
          description: Field name with error
          type: string
        message:
          description: Error message for the field
          type: string
      type: object
  securitySchemes:
    petstore_auth:
      description: OAuth 2.0 authentication for Petstore API
      flows:
        authorizationCode:
          authorizationUrl: https://petstore.com/oauth/authorize
          scopes:
            read:pets: Read pets
            write:pets: Write pets
            admin:pets: Admin access to pets
          tokenUrl: https://petstore.com/oauth/token
        implicit:
          authorizationUrl: https://petstore.com/oauth/authorize
          scopes:
            read:pets: Read pets
            write:pets: Write pets
            admin:pets: Admin access to pets
      type: oauth2
    api_key:
      description: API key for authentication
      in: header
      name: X-API-Key
      type: apiKey

Generation Details

config.yaml

generatorName: go-gin-server
outputDir: ./generated
inputSpec: ./petstore-api.yaml
modelNamePrefix: Api
additionalProperties:
  generateInterfaces: true
  apiPath: go
  interfaceOnly: true
  packageName: my_api
  serverPort: "9000"

openapi-generator-cli generate -c openapi-gen-petstore.yaml

Steps to reproduce

Related issues/PRs

Suggest a fix

Reproduce the issue with the provided petstore-api.yaml and the Go generator using modelNamePrefix or modelNameSuffix set to Api. Inspect the generated api_model_pet.go and the Go generator's model-name handling; done means the Tags field refers to ApiTag rather than ApiApiTag for both prefix and suffix cases.