oneOf variant listed twice in request-body example dropdown when its subtree contains an unrelated nested oneOf

[ahridin]

RapiDoc version: 9.3.8 (also present as of the current latest, 9.3.8 — no newer release exists yet)

Bug: When a request body schema is a top-level oneOf (with discriminator.mapping), the EXAMPLE dropdown lists a variant twice instead of once, but only if that variant's schema subtree transitively contains an unrelated, independent nested oneOf somewhere deeper (e.g. a property that is itself oneOf: [string, SomeObject]). Variants with no nested oneOf in their subtree render correctly, once each.

Repro spec (OpenAPI 3.1):

{
  "openapi": "3.1.0",
  "info": { "title": "oneOf duplicate example repro", "version": "1.0.0" },
  "paths": {
    "/things": {
      "post": {
        "requestBody": {
          "content": {
            "application/json": { "schema": { "$ref": "#/components/schemas/Request" } }
          }
        },
        "responses": { "200": { "description": "ok" } }
      }
    }
  },
  "components": {
    "schemas": {
      "Request": {
        "oneOf": [
          { "$ref": "#/components/schemas/PlainVariant" },
          { "$ref": "#/components/schemas/NestedOneOfVariant" }
        ],
        "discriminator": {
          "propertyName": "kind",
          "mapping": {
            "plain": "#/components/schemas/PlainVariant",
            "nested": "#/components/schemas/NestedOneOfVariant"
          }
        }
      },
      "PlainVariant": {
        "type": "object",
        "properties": {
          "kind": { "type": "string", "enum": ["plain"] },
          "value": { "type": "string" }
        }
      },
      "NestedOneOfVariant": {
        "type": "object",
        "properties": {
          "kind": { "type": "string", "enum": ["nested"] },
          "entry": { "$ref": "#/components/schemas/EntryRef" }
        }
      },
      "EntryRef": {
        "oneOf": [
          { "type": "string" },
          { "$ref": "#/components/schemas/EntryObject" }
        ]
      },
      "EntryObject": {
        "type": "object",
        "properties": { "id": { "type": "string" } }
      }
    }
  }
}

Steps to reproduce:

1. Load the spec above via <rapi-doc spec-url="..."> with rapidoc@9.3.8.
2. Open the POST /things operation, go to the request body's EXAMPLE dropdown.
3. Expected: 2 entries, PlainVariant and NestedOneOfVariant, each once.
4. Actual: NestedOneOfVariant appears twice; PlainVariant (which has no nested oneOf) appears once. The trigger is specifically the nested, unrelated oneOf in EntryRef — it's unrelated to the top-level discriminator.

Isolation notes: We built up to this minimal case incrementally: a flat top-level oneOf with 2 variants (no duplication) → adding allOf-based composition to each variant (still no duplication) → adding a nested oneOf to only one variant's subtree (that variant, and only that variant, doubles in the dropdown). This isolates the nested oneOf as the trigger, independent of the discriminator/allOf mechanics.

Real-world impact: In our OpenAPI 3.1 spec, a top-level oneOf Request schema (10 discriminated variants) has every variant transitively referencing a schema that is itself oneOf: [string, SomeObject] via a sessions array property — so all 10 variants appear twice in the request-body EXAMPLE dropdown (20 entries, each name duplicated back-to-back).