[Bug]: No casting applied if type is object

[jonathanberthias]

Actual Behavior

When validating a request, I get a different validation error depending on the structure of the schema.

If I have the following schema:

Pet:
 type: object # <-- this causes the difference
 properties:
 id:
 type: integer
Pet2:
 allOf:
 - properties:
 id:
 type: integer

and send a request with body {"id": "hello"},

with the first schema I get:

openapi_core.casting.schemas.exceptions.CastError: Failed to cast value to integer type: hello

whereas in the second one I get:

openapi_core.validation.schemas.exceptions.InvalidSchemaValue: Value {'id': 'hello'} not valid for schema of type any: (<ValidationError: "'hello' is not of type 'integer'">,)

Expected Behavior

These schemas are equivalent, and as such I expected to get the same error. Specifically, I expected the validation error in both cases rather than the casting error as I asked for request validation.
Also, removing the type: object in the first schema seems to bypass casting entirely and leads to the same validation error as the second schema.

Steps to Reproduce

schema.yaml

openapi: "3.0.0"
info:
 title: "Sample API"
 version: "1.0.0"
servers:
 - url: /
paths:
 /pets:
 post:
 summary: Create a pet
 operationId: createPet
 requestBody:
 content:
 application/json:
 schema:
 $ref: "#/components/schemas/Pet"
 responses:
 '201':
 description: Created
 content:
 application/json:
 schema:
 $ref: "#/components/schemas/Pet"
 /pets2:
 post:
 summary: Create a pet
 operationId: createPet2
 requestBody:
 content:
 application/json:
 schema:
 $ref: "#/components/schemas/Pet2"
 responses:
 '201':
 description: Created
 content:
 application/json:
 schema:
 $ref: "#/components/schemas/Pet"
components:
 schemas:
 Pet:
 type: object # <-- this causes the difference
 properties:
 id:
 type: integer
 Pet2:
 allOf:
 - properties:
 id:
 type: integer

import json
import traceback
import openapi_core
from openapi_core.contrib.starlette import StarletteOpenAPIRequest
from starlette.requests import Request


def starlette_request(path: str):
 return Request({
 "type": "http",
 "method": "POST",
 "path": path,
 "headers": [(b"content-type", b"application/json")],
 "query_string": "",
 })


body = json.dumps({"id": "hello"})

openapi = openapi_core.OpenAPI.from_file_path("schema.yaml")
try:
 openapi.validate_request(
 StarletteOpenAPIRequest(starlette_request("/pets"), body=body)
 )
except openapi_core.exceptions.OpenAPIError:
 traceback.print_exc()

try:
 openapi.validate_request(
 StarletteOpenAPIRequest(starlette_request("/pets2"), body=body)
 )
except openapi_core.exceptions.OpenAPIError:
 traceback.print_exc()

OpenAPI Core Version

0.19.0

OpenAPI Core Integration

starlette

Affected Area(s)

casting, validation

References

No response

Anything else we need to know?

No response

Would you like to implement a fix?

None