Fix S3925 FP: serialization infrastructure breaking change in .NET 8

[IeuanWalker]

I have this custom exception -

[Serializable]
public class CalendarDateChangedException : Exception
{
	public CalendarDateChangedException()
	{
	}

	public CalendarDateChangedException(string? message) : base(message)
	{
	}

	public CalendarDateChangedException(string? message, Exception? innerException) : base(message, innerException)
	{
	}

	protected CalendarDateChangedException(SerializationInfo info, StreamingContext context) : base(info, context)
	{
	}
}

Retarged the application from .net 7 to 8, i get this warning -

Warning	SYSLIB0051	'Exception.Exception(SerializationInfo, StreamingContext)' is obsolete: 'This API supports obsolete formatter-based serialization. It should not be called or extended by application code.' (https://aka.ms/dotnet-warnings/SYSLIB0051)	

Removing the last method, i then get this warning -

Warning	S3925	Update this implementation of 'ISerializable' to conform to the recommended serialization pattern.

[cristian-ambrosini-sonarsource]

Hi @IeuanWalker!

I think the warning that you are experiencing is caused by this .Net 8 breaking change. Do you need your custom exception type to be serializable? If not, you can follow the recommended action (see "If you're creating a custom System.Exception-derived type" section), and remove the [Serializable] attribute, this way S3925 should not raise.

[IeuanWalker]

thanks @cristian-ambrosini-sonarsource, thats good to know 🙂

[Wouter29]

This is not working @cristian-ambrosini-sonarsource
If I make a custom Exception like this

    public class CustomException : Exception
    {
    }

It still triggers a "S3925:"ISerializable" should be implemented correctly" that only can be solved by adding a suppression.

[cristian-ambrosini-sonarsource]

Hi @Wouter29! We are starting a dedicated effort over the next 2 weeks to address serialization rules post-Net8 (see #8377). Please follow the mentioned issue to stay updated on the progress.

cheers!

[martin-strecker-sonarsource]

The [Serializable] attribute applied in the code example is an indication, that binary formatting support is intended. Therefore S3925 is raised if the serialization constructor is missing.
You need to remove the [Serializable] attribute and the serialization constructor from the type.
See also #7673

[AlexEngblom]

Cannot get rid of warning S3925 with these recommendations (also documented here https://learn.microsoft.com/en-us/dotnet/fundamentals/syslib-diagnostics/syslib0051).