JSchemaGenerationProvider for MemberProperty not executed if annotation exists on metadatatype buddy class

[JeffBarnard]

I want to use a custom JSchemaGenerationProvider to add some properties that aren't supported out of the box, such as "readOnly".

I am using ef-core database first tools to generate portable POCO classes.
I am then extending these classes by adding 'buddy classes' to annotate them for the validation rules.

    public partial class Model 
    {
        public string Name { get; set; }
    }

    [MetadataType(typeof(IModelMeta))]   
    public partial class Model : IModelMeta
    {
       
    }

    public interface IModelMeta
    {
        [JSchemaGenerationProvider(typeof(CustomSchemaProvider))]        
        [ReadOnly(true)] // "readOnly": true   
        string Name { get; set; }
    }

In the above example, my CustomSchemaProvider is not executed.

Even if I do not use an interface and use a local class instead, it still does not work:

[MetadataType(typeof(ModelMeta))]   
public partial class Model
{
    public class ModelMeta
    {
        [JSchemaGenerationProvider(typeof(CustomSchemaProvider))]
        [ReadOnly(true)] // "readOnly": true   
        public string Name { get; set; }

It only works if I move the annotation to the origin class definition, but I cannot do this because my base partial POCO classes are generated by tooling (efpt).

[JeffBarnard]

I have other code that detects metadata attributes and it basically looks like this:

var metadataType = type.GetCustomAttributes(typeof(MetadataTypeAttribute), true)
 .OfType<MetadataTypeAttribute>().FirstOrDefault();

if (metadataType != null) 
{
    PropertyInfo[] properties = metadataType.MetadataClassType.GetProperties(BindingFlags.Public | ...);

Perhaps there is a workaround, a method that I could override to fetch the metadata properties, then I could apply a similar technique there.

[JeffBarnard]

When using the .net ValidationContext to validate our objects, the metadata classes need to be registered in order for that api to detect them. I don't know why they require us to do this, but perhaps this is a useful reference:

foreach (MetadataTypeAttribute attrib in type.GetCustomAttributes(typeof(MetadataTypeAttribute), true))
{
    System.ComponentModel.TypeDescriptor.AddProviderTransparent(
        new AssociatedMetadataTypeTypeDescriptionProvider(type, attrib.MetadataClassType), type);
}