separating required properties from schema object generates Record<string, never>

[xinruix]

openapi-typescript version

7.0.0-next.8

Node.js version

20

OS + version

macOS 15.2

Description

When separating out the required properties into its own schema, an additional type of Record<string, never> is generated onto the type which does not allow me to update the fields on the generated type. It also does not make the types required as specified in the OpenApi spec.

Reproduction

Hi, I was looking to follow this blog where ideally I can separate out properties to be reused in different methods(get/patch)
https://blog.stoplight.io/reuse-openapi-descriptions

So let's say I have the following schema
paths: '/customers': post: tags: - Customer requestBody: $ref: '#/components/requestBodies/CreateCustomer' responses: 201: description: Created content: application/json: schema: $ref: '#/components/schemas/CustomerId' components: schemas: Customer: allOf: - $ref: '#/components/schemas/CustomerProperties' - $ref: '#/components/schemas/CustomerRequiredProperties'
CustomerProperties:
type: object
properties:
FirstName:
type: string
LastName:
type: string
DOB:
type: string
format: date-time
Segment:
type: string
enum:
- Young
- MiddleAged
- Old
- Moribund
CustomerRequiredProperties:
type: object
required:
- FirstName
- LastName
- DOB`

Splitting out this into CustomerRequiredProperties generates Record<string, never> onto the type

Expected result

I would expect to have a Customer object that has the required properties of FirstName,LastName and DOB

Required

• My OpenAPI schema is valid and passes the Redocly validator (npx @redocly/cli@latest lint)

Extra

• I’m willing to open a PR (see CONTRIBUTING.md)