[BUG] [Go] Go SDK breaks for parent schema names with special character(._)

[mohamuni]

Bug Report Checklist

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

Description

While generating Go SDK with OpenAPI Generator, if a composite schema's parent schema contains names with special characters (. _) and a discriminator is defined on the parent schema, Go SDK fails because the sanitized name of the parent model is not used in the composite schema model.

openapi-generator version

Latest version(7.5.0)

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: Test
  version: 1.0.0
paths: {}
components:
  schemas:
    FinalItem:
      type: object
      allOf:
        - $ref: '#/components/schemas/Base.Item'
        - $ref: '#/components/schemas/AdditionalData'
    Base.Item:
      type: object
      properties:
        title:
          type: string
        type:
          type: string
          enum:
            - FINAL
          example: FINAL
      discriminator:
        propertyName: type
        mapping:
          FINAL: '#/components/schemas/FinalItem'
      required:
        - title
        - type
    AdditionalData:
      type: object
      properties:
        prop1:
          type: string
        quantity:
          type: integer
          format: int32
          example: 1
          minimum: 1
        unitPrice:
          type: number
          format: double
          example: 9.99
          minimum: 0.0
        totalPrice:
          type: number
          format: double
          example: 9.99
          minimum: 0.0
      required:
        - sku
        - quantity
        - unitPrice
        - totalPrice

Generation Details

mvn clean install
java -jar openapi-generator-cli-7.5.0.jar generate -i example.yaml -g go -o gosdk

Steps to reproduce

Generate the Go SDK with the specified spec file and observe that the parent schema model name in the composite schema model is not sanitized.

Actual Parent model file

type BaseItem struct {
	Title string `json:"title"`
	Type string `json:"type"`
}

Actual Composite model file
when referring to the parent schema Base.Item which is not sanitized name, it leads to failure of generated SDK, Instead of referring to sanitized name(BaseItem) of parent model

type FinalItem struct {
	Base.Item
	Prop1 *string `json:"prop1,omitempty"`
	Quantity int32 `json:"quantity"`
	UnitPrice float64 `json:"unitPrice"`
	TotalPrice float64 `json:"totalPrice"`
}

Expected model definition in Composite schema model file.

type FinalItem struct {
	BaseItem
	Prop1 *string `json:"prop1,omitempty"`
	Quantity int32 `json:"quantity"`
	UnitPrice float64 `json:"unitPrice"`
	TotalPrice float64 `json:"totalPrice"`
}

Suggest a fix

In following file, when checking for parent model for composite schema, specify to use parentmodel.classname instead of parentmodel.name
https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/go/model_simple.mustache

Following changes are suggested along with line numbers

6	{{#parentModel.name}}
7	{{^isArray}}
8		{{{parentModel.classname}}}
9	{{/isArray}}
10	{{#isArray}}
11		Items {{{parentModel.classname}}}
12	{{/isArray}}
13	{{/parentModel.name}}

[vvb]

cc @wing328 @rikotsev I think this regression was introduced by the changes made in #18390

We would appreciate your views on this.

[wing328]

In following file, when checking for parent model for composite schema, specify to use parentmodel.classname instead of parentmodel.name

please file a PR with the suggested fix when you've time.

[vvb]

Done