Valid call returns 500 without neither logging nor validation error

[walles]

With openapi-cop 5cb4e9f988cc7150374db3b3dad383281eaf7c8d running in Docker, I get a 500 back from the proxy but no indication of any errors.

I would expect one of:

1. The original (valid) 404 response
2. An explanation of what's wrong, both on the openapi-cop console and in the Openapi-Cop-Validation-Result header I got back

Sequence Diagram

sequenceDiagram
    Test Driver->>openapi-cop: DELETE /internal/test/plans
    openapi-cop->>App Under Test: DELETE /internal/test/plans
    App Under Test->>openapi-cop: 404 (documented response)
    openapi-cop->>Test Driver: 500

Log Output

Console output, note the "valid": true line.

pfcapi-openapi-cop-1            | 2022-12-13T12:33:40.431Z openapi-cop:proxy Received server response with status code 404
pfcapi-openapi-cop-1            | 2022-12-13T12:33:40.432Z openapi-cop:proxy Validation results [DELETE /internal/test/plans] {
pfcapi-openapi-cop-1            |   "request": {
pfcapi-openapi-cop-1            |     "valid": true,
pfcapi-openapi-cop-1            |     "errors": null
pfcapi-openapi-cop-1            |   }
pfcapi-openapi-cop-1            | }

Received by Test Driver

Note the combination of 500 and \"valid\":true.

HTTP/1.1 500 Internal Server Error
Connection: close
Date: Tue, 13 Dec 2022 12:33:40 GMT
Openapi-Cop-Source-Request: {\"method\":\"DELETE\",\"path\":\"/internal/test/plans\",\"headers\":{\"host\":\"subscriptions:5048\",\"user-agent\":\"Go-http-client/1.1\",\"authorization\":\"Basic ***\",\"x-request-id\":\"***\",\"x-span-parent-id\":\"***\",\"accept-encoding\":\"gzip\",\"connection\":\"close\"},\"query\":{}}
Openapi-Cop-Validation-Result: {\"request\":{\"valid\":true,\"errors\":null}}
X-Powered-By: Express
Content-Length: 0

Openapi-Cop-Source-Request

Expanded from ^

{
    "method": "DELETE",
    "path": "/internal/test/plans",
    "headers": {
        "host": "subscriptions:5048",
        "user-agent": "Go-http-client/1.1",
        "authorization": "Basic ***",
        "x-request-id": "***",
        "x-span-parent-id": "***",
        "accept-encoding": "gzip",
        "connection": "close"
    },
    "query": {}
}