OpenAPI sometimes add trailing number to model names

[Thijmen]

Hi there,

Unsure if I should've created an issue or not, but here we are. I am using Microsoft.AspNetCore.OpenApi 9.0.3 and sometimes, when there are no code changes and I re-build the code and access the Scalar web interface (and thus the OpenAPI spec), it adds a trialing number to my model name. Often the same, but seems at random as well.

For instance, I got a UserDto and now it shows UserDto2 in the OpenAPI. There is no UserDto as a model in the API spec.
Often, stopping the application and cleaning, then re-run works.

This is how my config looks like:

collection.AddOpenApi(options =>
        {
            options.AddSchemaTransformer<RequireNotNullableSchemaFilter>();

            options.AddOperationTransformer(
                (operation, context, arg3) =>
                {
                    if (
                        string.IsNullOrEmpty(operation.OperationId)
                        && context.Description.ActionDescriptor
                            is ControllerActionDescriptor controllerActionDescriptor
                    )
                    {
                        operation.OperationId = controllerActionDescriptor.ActionName;
                    }

                    return Task.CompletedTask;
                }
            );

          
            options.AddDocumentTransformer(
                (doc, context, ct) =>
                {
                    doc.Info.Title = "CloudCrafter API";
                    doc.Info.Version = "v1";

                    // Removed for Kubb generation to prevent baseURL being added to clients
                    doc.Servers = [];
                    return Task.CompletedTask;
                }
            );
        });
public class RequireNotNullableSchemaFilter : IOpenApiSchemaTransformer
{
    public Task TransformAsync(
        OpenApiSchema schema,
        OpenApiSchemaTransformerContext context,
        CancellationToken cancellationToken
    )
    {
        if (schema.Properties == null)
        {
            return Task.CompletedTask;
        }

        schema.Required ??= new HashSet<string>();

        foreach (var property in schema.Properties)
        {
            if (!property.Value.Nullable)
            {
                schema.Required.Add(property.Key);
            }
        }

        return Task.CompletedTask;
    }
}

Is there a way I can debug this? I create my typescript interfaces based off these model names, so adding a trailing number every now and then complicates stuff.

[Thijmen]

Im beginning to think it has to do with the RequireNotNullableSchemaFilter, because when I dont use that filter, I haven't gotten any numbers in my DTO's. However, this is not an option for me, because I need to require those properties in the OpenAPI spc