Support custom keywords in schema generation

[ProTip]

Nuget Package

JsonSchema.Net

Package Version

6.0.3

Operating System

Linux

.Net Target (if relevant, please specify the version in the description)

.Net (5 or after)

A clear and concise description of the bug.

If I don't register the keyword by passing in a JsonSerializerContext it will throw the following error when serializing the schema:

Unhandled exception. System.InvalidCastException: Unable to cast object of type 'UiPlaceholderKeyword' to type 'Json.Schema.UnrecognizedKeyword'

What did you expect?

The documentation does not mention needing a serializer context passed through, so I expected the schema to serialize without issue.

Please add test code or steps to reproduce the behavior.

Dotnet Fiddle: https://dotnetfiddle.net/hAgRn6

Is there any other information you'd like to share regarding this bug?

In #659 it was suggested this is due to running in an AOT context however:

• I'm not running in an AOT context(initially was setting up a POC in LINQPad)
• The documentation note added is missing information on arguments required for the overload

After moving my POC code from LINQPad to console project I was able to supply a JsonSerializerContext and confirm the schema would serialize without error.

P.S.: These Json projects are amazing and much appreciated.

Code of Conduct & Contributor Guidelines

• I agree to follow this project's Code of Conduct and Contribution Guidelines.

[gregsdennis]

Thanks for the report. I can work on this this week.

[gregsdennis]

Just had a look at your fiddle. It looks like you're trying to use a custom keyword in schema generation. That's not supported right now.

Thanks for the example, though. It'll help build out this feature.

[ProTip]

Cheers. Looks like that's what was going on in the referenced issue as well. I'm not blocked by this since I can just supply a JsonSerializerContext and get the desired results.

[gregsdennis]

I created a test for this because it seemed that serialization probably wasn't a generation problem (and if it was, providing a serializer context shouldn't have fixed it). Looks like it is actually a problem in the main schema lib.

[gregsdennis]

@ProTip please grab JsonSchema.Net v6.0.4 and see if that fixes the problem. If not, then there's something wrong with the generation lib, too.

[ProTip]

Yes, it's working working for me now without needing to supply a JsonSerializationContext!