[BUG] [Typescript-fetch]

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?
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Description

When self referencing component is defined with inheritance, typescript import is added to itself and you get conflicting components in one file.

openapi-generator version

6.4.0

OpenAPI declaration file content or url

openapi: "3.0.3"
info:
  title: Self reference reproduce
  version: 1.0.0
tags:
  - name: Menus

paths:
  /menus:
    get:
      tags:
        - Menus
      operationId: GetMenus
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/GetMenusResponse"

components: 
  schemas:   
    GetMenusResponse:
      type: object
      properties:
        menuItems:
          type: array
          items:
            $ref: "#/components/schemas/MenuItem"  

    LabelItem:
      type: object
      properties:       
        label:
          type: string               

    MenuItem:
      type: object
      allOf:        
        - $ref: '#/components/schemas/LabelItem'
      properties:
        name:
          type: string
        children:
          type: array
          items:
            $ref: "#/components/schemas/MenuItem"      

Generation Details

Due the self referencing, it generates import statement to import itself in MenuItem.ts:

import type { MenuItem } from './MenuItem';
...
export interface MenuItem {

Also noticed, that problem exists only if there's inheritance, if I remove

      allOf:        
        - $ref: '#/components/schemas/LabelItem'

problem goes away.

Steps to reproduce

1. Create folder C:\temp\typescript-self-reference-issue-reproduce
2. Save the above mentioned spec to spec.yaml
3. Run (jar path might need to be adjusted to you local cache)

 java -jar ".\node_modules\@openapitools\openapi-generator-cli\versions\6.4.0.jar" generate --input-spec="C:\temp\typescript-self-reference-issue-reproduce\spec.yaml" --generator-name="typescript-fetch" --output="C:\temp\typescript-self-reference-issue-reproduce/src"

4. Inspect ./src/models/MenuItem.ts. It should contain import to itself.

Suggest a fix

You can't fix that in templates, only in generator itself.

I was looking at
https://github.com/OpenAPITools/openapi-generator/blob/1204662a6485611f427106b3d734c54f36cc49bb/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java#L766

where I think imports array is generated, but could not understand from reading the code why it works correctly without inheritance, probably would need to debug and as long as I'm not a java developer, it would take significant effort to set everything up.

Reproduce the issue with the supplied OpenAPI YAML and the typescript-fetch generation command, then inspect src/models/MenuItem.ts. Start with TypeScriptFetchClientCodegen.java around the referenced imports logic and trace how inheritance affects the generated imports. Done means the generated MenuItem.ts no longer imports itself while preserving the inherited and self-referencing model behavior.