[BUG] [typescript] Invalid typescript generated for inheriting component with union typed children

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

When generating from a schema having a component with allOf and one of its properties is an array of oneOf, the name-resolution for files creates invalid file-names. When removing the allOf of the components schema and adding a definition of the fields, it works as expected.

openapi-generator version

Tested using 6.4.0 and 6.5.0

OpenAPI declaration file content or url

{
    "openapi": "3.0.1",
    "info": {
      "title": "Media Api",
      "version": "v1"
    },
    "paths": {
      "/browse": {
        "get": {
          "responses": {
            "200": {
              "description": "Success",
              "content": {
                "application/json": {
                  "schema": {
                    "type": "array",
                    "items": {
                      "$ref": "#/components/schemas/AlbumModel"
                    }
                  }
                }
              }
            }
          }
        }
      }
    },
    "components": {
      "schemas": {
        "AlbumModel": {
          "type": "object",
          "allOf": [
            {
              "$ref": "#/components/schemas/IAlbumModel"
            }
          ],
          "properties": {
            "children": {
              "type": "array",
              "items": {
                "oneOf": [
                  {
                    "$ref": "#/components/schemas/TrackWithTitleModel"
                  },
                  {
                    "$ref": "#/components/schemas/TrackModel"
                  }
                ]
              },
              "nullable": true
            }
          },
          "additionalProperties": false
        },
        "IAlbumModel": {
          "type": "object",
          "properties": {
            "id": {
              "type": "integer",
              "format": "int32"
            }
          },
          "additionalProperties": false
        },
        "IDocumentModel": {
          "type": "object",
          "properties": {
            "id": {
              "type": "integer",
              "format": "int32"
            }
          },
          "additionalProperties": false
        },
        "TrackWithTitleModel": {
          "type": "object",
          "allOf": [
            {
              "$ref": "#/components/schemas/TrackModel"
            }
          ],
          "properties": {
            "title": {
              "type": "string"
            }
          },
          "additionalProperties": false
        },
        "TrackModel": {
          "type": "object",
          "allOf": [
            {
              "$ref": "#/components/schemas/IDocumentModel"
            }
          ],
          "additionalProperties": false
        }
      }
    }
  }

Generation Details

Generating using node package @openapitools/openapi-generator-cli. The bug seems to be present in at least many of the typescript packages. I've tested rsjs, fetch and node.

The invalid file is models/AlbumModel.ts, which starts with import-statements like:

import { exists, mapValues } from '../runtime';
import type { TrackWithTitleModel | TrackModel } from './TrackWithTitleModel | TrackModel';
import {
    TrackWithTitleModel | TrackModelFromJSON,
    TrackWithTitleModel | TrackModelFromJSONTyped,
    TrackWithTitleModel | TrackModelToJSON,
} from './TrackWithTitleModel | TrackModel';

Steps to reproduce

java -jar "6.5.0.jar" generate --input-spec="./openapi.json" --generator-name="typescript-fetch" --output="./src"

Related issues/PRs

Strongly related to:

• https://github.com/OpenAPITools/openapi-generator/issues/14601

Maybe also related to:

• https://github.com/OpenAPITools/openapi-generator/issues/12256
• https://github.com/OpenAPITools/openapi-generator/issues/5202

Suggest a fix

Produce the same output as if I would define the properties of IAlbumModel, of which AlbumModel inherits, inside it.

Here's a sample definition which will produce the expected result of the one above:

{
    "openapi": "3.0.1",
    "info": {
      "title": "Media Api",
      "version": "v1"
    },
    "paths": {
      "/browse": {
        "get": {
          "responses": {
            "200": {
              "description": "Success",
              "content": {
                "application/json": {
                  "schema": {
                    "type": "array",
                    "items": {
                      "$ref": "#/components/schemas/AlbumModel"
                    }
                  }
                }
              }
            }
          }
        }
      }
    },
    "components": {
      "schemas": {
        "AlbumModel": {
          "type": "object",
          "properties": {
            "id": {
              "type": "integer",
              "format": "int32"
            },
            "children": {
              "type": "array",
              "items": {
                "oneOf": [
                  {
                    "$ref": "#/components/schemas/TrackWithTitleModel"
                  },
                  {
                    "$ref": "#/components/schemas/TrackModel"
                  }
                ]
              },
              "nullable": true
            }
          },
          "additionalProperties": false
        },
        "IDocumentModel": {
          "type": "object",
          "properties": {
            "id": {
              "type": "integer",
              "format": "int32"
            }
          },
          "additionalProperties": false
        },
        "TrackWithTitleModel": {
          "type": "object",
          "allOf": [
            {
              "$ref": "#/components/schemas/TrackModel"
            }
          ],
          "properties": {
            "title": {
              "type": "string"
            }
          },
          "additionalProperties": false
        },
        "TrackModel": {
          "type": "object",
          "allOf": [
            {
              "$ref": "#/components/schemas/IDocumentModel"
            }
          ],
          "additionalProperties": false
        }
      }
    }
  }

Start with the provided Java generation command and inspect the generated models/AlbumModel.ts output for the invalid union-based import paths and identifiers. Reproduce with the supplied OpenAPI declaration and verify that the TypeScript models generate valid imports and match the expected output when inherited properties are handled.