[Bug]: OAS 3.1 list-style "type" raises in SchemaCaster and StyleDeserializersFactory

Start with the reproduced call to oas31_schema_casters_factory.create and inspect SchemaCaster and StyleDeserializersFactory, especially where SchemaPath values are read. Check how SchemaPath.read_str_or_list can support both string and list-form type values, then rerun the provided casting example and verify style deserialization also handles the OpenAPI 3.1 form.

Actual Behavior

When a schema uses OpenAPI 3.1's list form for type (e.g. type: ["string", "integer"]), parameter casting and style deserialization fail.

It works okay in version 0.19.5, but does not work in version 0.23.1 (I did not test the versions in between).

Expected Behavior

Per the OpenAPI 3.1 specification, type may be either a string or a non-empty array of strings.

Steps to Reproduce

from openapi_core.casting.schemas import oas31_schema_casters_factory
from jsonschema_path import SchemaPath

spec = {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": ["string", "number", "boolean"]
}

schema = SchemaPath.from_dict(spec)
oas31_schema_casters_factory.create(spec, schema).cast("42")

This snippet raises TypeError: Expected a string value, got <class 'list'>.

OpenAPI Core Version

0.23.1

OpenAPI Core Integration

flask

Affected Area(s)

casting, deserializing.

References

No response

Anything else we need to know?

jsonschema_path.SchemaPath already exposes read_str_or_list. So we should use it.

Would you like to implement a fix?

Yes