Raw binary request/response body (application/octet-stream) generates String instead of Resource

[joseegman-idoneea]

Description

A raw binary request/response body — type: string, format: binary not wrapped in a multipart object (e.g. application/octet-stream) — is generated as String instead of a binary type.

Binary → file type was only applied to object properties (MultipartFile, via ModelBuilder) and, after #387, to array items. The top-level content path (MapperPathUtil.getObjectOrType) has no binary detection.

Steps to reproduce

paths:
  /upload:
    post:
      operationId: uploadBinary
      requestBody:
        required: true
        content:
          application/octet-stream:
            schema:
              type: string
              format: binary
      responses:
        '200':
          description: OK

Actual result

default ResponseEntity<Void> uploadBinary(@Valid @RequestBody String resource) { ... }

Expected result

A streaming binary type:

default ResponseEntity<Void> uploadBinary(@Valid @RequestBody Resource resource) { ... }

(org.springframework.core.io.Resource; the reactive flavor wraps it as Mono<Resource>.)

Root cause

MapperPathUtil.getObjectOrType switches on the schema type and, for type: string, falls through to the default -> String branch without ever calling ApiTool.isBinary. MapperPathUtil.mapContentObject only builds a wrapping schema object for form-data media types, so a non-multipart binary body is typed purely by getObjectOrType.

Notes

Resource is used (not MultipartFile) because MultipartFile is a multipart-part type; a raw @RequestBody binary payload is idiomatically a streaming Resource.

Environment

• OpenAPI code generator (multiapi-engine), annotated + reactive server interface templates.
• Reproduced on main.