[Bug]: Query parameter validation fails to match empty string when listed as a valid enum value

[Youssef1313]

Actual Behavior

Run the following code:

from openapi_core import OpenAPI
from openapi_core.testing import MockRequest

SPEC = {
 "openapi": "3.2.0",
 "info": {"title": "Sample", "version": "1.0.0"},
 "paths": {
 "/api": {
 "get": {
 "tags": ["Sample"],
 "parameters": [
 {
 "name": "status",
 "in": "query",
 "schema": {"enum": ["Active", "Inactive", "Pending", ""]},
 }
 ]
 }
 }
 },
 "tags": [{"name": "Sample"}],
}

openapi = OpenAPI.from_dict(SPEC)

# Empty query parameter: status=
request = MockRequest(
 host_url="http://localhost",
 method="get",
 path="/api",
 args={"status": ""},
)

if hasattr(openapi, "iter_request_errors"):
 errors = list(openapi.iter_request_errors(request))
 if errors:
 print("INVALID")
 for e in errors:
 print(f" {type(e).__name__}: {e}")
 else:
 print("VALID")
else:
 try:
 openapi.validate_request(request)
 print("VALID")
 except Exception as exc:
 print("INVALID")
 print(f" {type(exc).__name__}: {exc}")

It prints:

INVALID
 ParameterValidationError: Query parameter error: status

Expected Behavior

It should print VALID.

OpenAPI Core Version

0.23.1

See OAI/OpenAPI-Specification#5411