René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[0.16.2 regression]  `{\"key\": null}` fails to validate as `{\"type\": \"object\"}`","articleBody":"In 0.16.1, `{\"key\": null}` validated successfully against `{\"type\": \"object\"}`—an object that includes a `null` value is still an object. But in 0.16.2 this incorrectly raises `openapi_core.unmarshalling.schemas.exceptions.InvalidSchemaValue: Value None not valid for schema of type any: (\u003cValidationError: 'None for not nullable'\u003e,)`.\r\n\r\nThis regression was introduced by commit 692a9156abd99a63cfbaf018bf26470d0060b702 (#434).\r\n\r\nFull reproducible example:\r\n\r\n```python\r\nfrom openapi_core import Spec\r\nfrom openapi_core.testing import MockRequest\r\nfrom openapi_core.validation.request import openapi_request_validator\r\n\r\nspec = Spec.create(\r\n    {\r\n        \"openapi\": \"3.0.3\",\r\n        \"info\": {\"title\": \"test\", \"version\": \"0\"},\r\n        \"paths\": {\r\n            \"/test\": {\r\n                \"post\": {\r\n                    \"parameters\": [\r\n                        {\r\n                            \"name\": \"obj\",\r\n                            \"in\": \"query\",\r\n                            \"content\": {\r\n                                \"application/json\": {\r\n                                    \"schema\": {\"type\": \"object\"},\r\n                                }\r\n                            },\r\n                        },\r\n                    ],\r\n                    \"responses\": {\"200\": {\"description\": \"\"}},\r\n                },\r\n            },\r\n        },\r\n    },\r\n)\r\nrequest = MockRequest(\r\n    \"http://localhost/\", \"post\", \"/test\", args={\"obj\": '{\"key\": null}'}\r\n)\r\nresult = openapi_request_validator.validate(spec, request)\r\nprint(result)\r\nresult.raise_for_errors()\r\n```\r\n","author":{"url":"https://github.com/andersk","@type":"Person","name":"andersk"},"datePublished":"2022-12-04T09:15:35.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/442/openapi-core/issues/442"}