fix: don't interpret simple parameter as deepObject

[fgreinacher]

Fixes #1565

[fgreinacher]

@RobbeSneyders Here is my take on a fix. It works fine in our application:

$ http :8080/api "filter[surname]_bogus"=="greinacher"
HTTP/1.1 400 Bad Request
Content-Length: 235
Content-Type: application/vnd.api+json; charset=utf-8
Date: Tue, 02 Aug 2022 14:56:31 GMT

{
    "errors": [
        {
            "code": "xrn:err:core:invalidRequestParameter",
            "detail": "Extra query parameter(s) filter[surname]_bogus not in spec",
            "id": "a6a0b17e-e52f-37e4-a7d9-6c2e926ed4f8",
            "status": "400",
            "title": "Invalid Request Parameter"
        }
    ]
}

[fgreinacher]

This is the first place where we know the root parameter name and have the schema information available. We already have a lot of special casing here, so that follow-up code can assume everything is fine. Let me know if you prefer to move that checker somewhere else.

[RobbeSneyders]

Thanks @fgreinacher!
I've submitted a PR to fix the failing tests due to a new Flask version: #1572. I'd like to merge that one first. Feel free to review it.

[fgreinacher]

Thanks @fgreinacher! I've submitted a PR to fix the failing tests due to a new Flask version: #1572. I'd like to merge that one first. Feel free to review it.

Thanks @RobbeSneyders, I was wondering how this failure could be related to my change :)

The MR looks good to me!

[fgreinacher]

@RobbeSneyders I'm planning the last days before my summer vacation. Do you think we could get this in early next week so I can verify it with our services? 🙇

[RobbeSneyders]

Sorry for the delay, I was on vacation myself :)
Should be good to go now. I'll prep a release.