[BUG] JSON source generators broken by 2.8.0

[ghelyar]

#529 added an internal JsonConverter<Value> that breaks source JSON source generators, as the JsonTypeInfo<Value> is not generated because it needs to create the converter in the generated code.

The possible fixes are to either make ValueJsonConverter public, so that people can add Value to their own source generators, or provide a public source generator for people to use e.g.

[JsonSerializable(typeof(Value))]
public partial class OpenFeatureJsonSerializerContext : JsonSerializerContext
{
}

[askpt]

Thanks for reporting this issue, @ghelyar!

Looking at your proposed solutions:

• Making ValueJsonConverter public: This seems more feasible, allowing users to reference it in their source generators.
• Providing a public source generator: This is my preferred approach, but it is impossible due to .NET Framework support. Since the SDK likely needs to maintain .NET Framework compatibility, shipping a source generator will create issues for those users. Source generators are only supported in .NET 5+ SDKs.

Making the JsonConverter public is the better solution here as it would solve the immediate problem without introducing compatibility concerns.

@WeihanLi, do you see any issues with making the ValueJsonConverter public? This would allow users to properly integrate the Value into their source generators while maintaining backwards compatibility.

@kylejuliandev, do you see any unit test scenario where we can prevent this from happening again?

[ghelyar]

Source generators are only supported in .NET 5+ SDKs

As far as I can tell you can add it to the project and it will at least build, including for the net462 target, but I have not tested it any further than that. It looks like it's just included as part of .NET 6+, and earlier versions back to net462 and netstandard2.0 can use the System.Text.Json package, which this project is already using.
https://learn.microsoft.com/en-us/dotnet/api/system.text.json.serialization.jsonserializableattribute#applies-to

Making ValueJsonConverter public also has some other advantages though like the user can more easily use their own JSON options, or they can include a Value as a property on their own type and then create a source generator for that type, so making ValueJsonConverter public is probably worth doing anyway.

For unit testing you would need a test project that has no InternalsVisibleTo access to anything, which is a good idea anyway so that you can test the public API of your library as a consumer would use it, and then you could put the source generator in there, along with any high level tests. The MSBuild JsonSerializerIsReflectionEnabledByDefault property can be set to false on the test project if you want to test that it can run with reflection disabled, e.g. to check that it's compatible with AOT compilation.

[WeihanLi]

breaks source JSON source generators

Ah, so sorry to hear that, should consider source generator support when it introduced.

do you see any issues with making the ValueJsonConverter public

Think it should be fine

Source generators are only supported in .NET 5+ SDKs

Think it's available for netstandard2.0 also, it relies on the compiler set