This is a test project to check if starting in .NET 9, JsonSerializer has (limited) support for non-nullable reference type enforcement in both serialization and deserialization. For reference see the following
- https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/nullable-annotations
- https://learn.microsoft.com/en-us/dotnet/api/system.text.json.jsonserializeroptions.respectnullableannotations?view=net-9.0#system-text-json-jsonserializeroptions-respectnullableannotations
This project contains a Person class with properties 'Name', 'Age' and 'Email'. The simple program class serializes and deserializes an instance of this class. The 'Name' property is non-nullable - the value cannot be null. But in .net 8 and .net 9, this is not enforced strictly and so even if a value is not set for 'Name', it will continue to serialize and deserialize as expected. This can be seen if you run the project as it is.
Starting with .net 9, we can enforce this check by using the 'RespectNullableAnnotations' options. Ensure that the annotations are set prior to testing this. This can be done either at the project level or at the code level.
For the project level, add the following in the csproj file
<Nullable>enable</Nullable>
For the code level, add the following before defining the options.
#nullable enable
Once the annotations are set, we can test this by uncommenting out line 38 and running the project. An exception is seen in console.
The property or field 'Name' on type 'Person' doesn't allow getting null values. Consider updating its nullability annotation.