JsonTypeInfoExtensions.GetSchemaReferenceId throws ArgumentOutOfRangeException for nested generic types

[kl1mm]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Hey together,
i have a constellation similar to the following:

...
app.Services.AddOpenApi();
...
app.MapOpenApi();

app.MapGet("/foo", () => new Foo<int>.Bar<string>.Baz { One = 1, Two = "hello" });

public static class Foo<T>
{
    public static class Bar<TT>
    {
        public class Baz
        {
            public required T One { get; set; }
            public required TT Two { get; set; }
        }
    }
}

When I try to access the generated openapi.json in the browser via http://<server>:<port>/openapi/v1.json I get an ArgumentOutOfRangeException.

The problem seems to be located in this part:

// The typesystem says Baz is a generic type but the name property does not have any ` characters 
// because it is nested and the declaring type is the generic one.

if (type.IsGenericType)
{
    var genericTypeName = type.Name[..type.Name.LastIndexOf('`')];
    var genericArguments = type.GetGenericArguments();
    var argumentNames = string.Join("And", genericArguments.Select(arg => arg.GetSchemaReferenceId(options)));
    return $"{genericTypeName}Of{argumentNames}";
}

Expected Behavior

Do not throw an exception and return either Baz or even better FooOfInt.BarOfString.Baz

Steps To Reproduce

No response

Exceptions (if any)

System.ArgumentOutOfRangeException    at System.ArgumentOutOfRangeException.ThrowNegative[T](T value, String paramName)
   at System.ArgumentOutOfRangeException.ThrowIfNegative[T](T value, String paramName)
   at System.String.ThrowSubstringArgumentOutOfRange(Int32 startIndex, Int32 length)
   at System.String.Substring(Int32 startIndex, Int32 length)
   at Microsoft.AspNetCore.OpenApi.JsonTypeInfoExtensions.GetSchemaReferenceId(Type type, JsonSerializerOptions options)
   at Microsoft.AspNetCore.OpenApi.JsonTypeInfoExtensions.GetSchemaReferenceId(JsonTypeInfo jsonTypeInfo, Boolean isTopLevel)
   at Microsoft.AspNetCore.OpenApi.OpenApiOptions.CreateDefaultSchemaReferenceId(JsonTypeInfo jsonTypeInfo)
   at Microsoft.AspNetCore.OpenApi.JsonNodeSchemaExtensions.ApplySchemaReferenceId(JsonNode schema, JsonSchemaExporterContext context, Func`2 createSchemaReferenceId)
   at Microsoft.AspNetCore.OpenApi.OpenApiSchemaService.\u003C\u003Ec__DisplayClass0_0.\u003C.ctor\u003Eb__2(JsonSchemaExporterContext context, JsonNode schema)
   at System.Text.Json.Schema.JsonSchema.\u003CToJsonNode\u003Eg__CompleteSchema|104_0(JsonNode schema, \u003C\u003Ec__DisplayClass104_0&)
   at System.Text.Json.Schema.JsonSchema.ToJsonNode(JsonSchemaExporterOptions options)
   at System.Text.Json.Schema.JsonSchemaExporter.GetJsonSchemaAsNode(JsonTypeInfo typeInfo, JsonSchemaExporterOptions exporterOptions)
   at System.Text.Json.Schema.JsonSchemaExporter.GetJsonSchemaAsNode(JsonSerializerOptions options, Type type, JsonSchemaExporterOptions exporterOptions)
   at Microsoft.AspNetCore.OpenApi.OpenApiSchemaService.CreateSchema(OpenApiSchemaKey key)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at Microsoft.AspNetCore.OpenApi.OpenApiSchemaStore.GetOrAdd(OpenApiSchemaKey key, Func`2 valueFactory)
   at Microsoft.AspNetCore.OpenApi.OpenApiSchemaService.GetOrCreateSchemaAsync(Type type, IServiceProvider scopedServiceProvider, IOpenApiSchemaTransformer[] schemaTransformers, ApiParameterDescription parameterDescription, Boolean captureSchemaByRef, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.OpenApi.OpenApiDocumentService.GetResponseAsync(ApiDescription apiDescription, Int32 statusCode, ApiResponseType apiResponseType, IServiceProvider scopedServiceProvider, IOpenApiSchemaTransformer[] schemaTransformers, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.OpenApi.OpenApiDocumentService.GetResponsesAsync(ApiDescription description, IServiceProvider scopedServiceProvider, IOpenApiSchemaTransformer[] schemaTransformers, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.OpenApi.OpenApiDocumentService.GetOperationAsync(ApiDescription description, HashSet`1 capturedTags, IServiceProvider scopedServiceProvider, IOpenApiSchemaTransformer[] schemaTransformers, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.OpenApi.OpenApiDocumentService.GetOperationsAsync(IGrouping`2 descriptions, HashSet`1 capturedTags, IServiceProvider scopedServiceProvider, IOpenApiOperationTransformer[] operationTransformers, IOpenApiSchemaTransformer[] schemaTransformers, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.OpenApi.OpenApiDocumentService.GetOpenApiPathsAsync(HashSet`1 capturedTags, IServiceProvider scopedServiceProvider, IOpenApiOperationTransformer[] operationTransformers, IOpenApiSchemaTransformer[] schemaTransformers, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.OpenApi.OpenApiDocumentService.GetOpenApiDocumentAsync(IServiceProvider scopedServiceProvider, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Builder.OpenApiEndpointRouteBuilderExtensions.\u003C\u003Ec__DisplayClass0_0.\u003C\u003CMapOpenApi\u003Eb__0\u003Ed.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Http.Generated.\u003CGeneratedRouteBuilderExtensions_g\u003EF56B68D2B55B5B7B373BA2E4796D897848BC0F04A969B1AF6260183E8B9E0BAF2__GeneratedRouteBuilderExtensionsCore.\u003C\u003Ec__DisplayClass2_0.\u003C\u003CMapGet0\u003Eg__RequestHandler|5\u003Ed.MoveNext()
--- End of stack trace from previous location ---
   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl.\u003CInvoke\u003Eg__Awaited|10_0(ExceptionHandlerMiddlewareImpl middleware, HttpContext context, Task task)

.NET Version

9.0.100

Anything else?

No response