False positive when adding optional property

When comparing these 2 schemas:

test/old.json

{
  "openapi": "3.0.0",
  "servers": [{ "url": "https://myserver.com" }],
  "info": { "title": "My API", "description": "Description", "version": "0.2.0" },
  "paths": {
    "/v1/entity/{id}": {
      "put": {
        "operationId": "myOperation",
        "description": "Some description",
        "requestBody": { "$ref": "#/components/requestBodies/updateBody" }
      }
    }
  },
  "components": {
    "schemas": {},
    "responses": {},
    "requestBodies": {
      "updateBody": {
        "description": "Update description",
        "content": {
          "application/json": {
            "schema": {
              "type": "object",
              "properties": {
                "url": { "type": "string", "description": "Some URL" }
              },
              "title": "updateBody",
              "additionalProperties": false
            }
          }
        }
      }
    },
    "parameters": {}
  }
}

test/new.json

{
  "openapi": "3.0.0",
  "servers": [{ "url": "https://myserver.com" }],
  "info": { "title": "My API", "description": "Description", "version": "0.2.0" },
  "paths": {
    "/v1/entity/{id}": {
      "put": {
        "operationId": "myOperation",
        "description": "Some description",
        "requestBody": { "$ref": "#/components/requestBodies/updateBody" }
      }
    }
  },
  "components": {
    "schemas": {},
    "responses": {},
    "requestBodies": {
      "updateBody": {
        "description": "Update description",
        "content": {
          "application/json": {
            "schema": {
              "type": "object",
              "properties": {
                "url": { "type": "string", "description": "Some URL" },
                "url2": { "type": "string", "description": "Some URL" }
              },
              "title": "updateBody",
              "additionalProperties": false
            }
          }
        }
      }
    },
    "parameters": {}
  }
}

I get a broken compatibility message:

docker run --rm -t -v $(pwd)/test/:/specs:ro openapitools/openapi-diff:latest --fail-on-incompatible  /specs/old.json /specs/new.json 
==========================================================================
==                            API CHANGE LOG                            ==
==========================================================================
                                  My API                                  
--------------------------------------------------------------------------
--                            What's Changed                            --
--------------------------------------------------------------------------
- PUT    /v1/entity/{id}
  Request:
        - Changed application/json
          Schema: Broken compatibility
--------------------------------------------------------------------------
--                                Result                                --
--------------------------------------------------------------------------
                 API changes broke backward compatibility                 
--------------------------------------------------------------------------

Note that the only change is the addition of the url2 optional property:

diff -u test/old.json test/new.json
--- test/old.json       2023-03-14 17:06:02
+++ test/new.json       2023-03-14 17:06:33
@@ -22,7 +22,8 @@
             "schema": {
               "type": "object",
               "properties": {
-                "url": { "type": "string", "description": "Some URL" }
+                "url": { "type": "string", "description": "Some URL" },
+                "url2": { "type": "string", "description": "Some URL" }
               },
               "title": "updateBody",
               "additionalProperties": false

Since the required field is absent, I would expect the addition of url2 to not create a broken compatibility error.

Inizia con i fixture forniti test/old.json e test/new.json e riproduci il risultato usando il comando Docker riportato nel report. Traccia il controllo di compatibilità dello schema del corpo della richiesta per una proprietà aggiunta senza un campo obbligatorio, quindi aggiungi un test di regressione e conferma che il confronto non segnali più una modifica incompatibile con le versioni precedenti.