Code generated by Json source generator results in warnings in projects with nullable enabled

[pranavkm]

I think it's an issue with the nullability annotations on the getters and setters for JsonMetadataServices.CreatePropertyInfo

These should be:

- Func<object, T>? getter,
+ Func<object, T?>? getter,

etc

[ghost]

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Issue Details

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I think it's an issue with the nullability annotations on the getters and setters for JsonMetadataServices.CreatePropertyInfo

These should be:

- Func<object, T>? getter,
+ Func<object, T?>? getter,

etc

Author:	pranavkm
Assignees:	-
Labels:	area-System.Text.Json, untriaged
Milestone:	-

[Trolldemorted]

Aren't the warnings correct in this case, because System.Text.Json ignores the non-nullability?

[layomia]

Aren't the warnings correct in this case, because System.Text.Json ignores the non-nullability?

There's robust logic in STJ to handle null on serialization and deserialization, including to support features like ignoring null on serialization. Because of this we don't leak NullReferenceException and related bugs. However, it would be most correct to accept T? on deserialization and return T? on serialization, since property values could indeed be null. Unfortunately, I couldn't find a way to express this in a prototype to have the correct semantics, due error CS0453 given this code.

In the fix for the issue #57178, I left the parameter type as Func<object, T>? getter and just banged the return value of the getter call in the generated code.