NSwag - cannot generate openapi json with generic Action delegate

[adam-clauss]

Basically, if one of the types that gets picked up contains a property of type Action, an exception gets thrown:

A repo project is here:
https://github.com/adam-clauss/nswag-test

It is a basic Web API app fresh from the VS 2022 template, just added nswag and an Action property to WeatherForecast (see WeatherForecast.cs, line 13.

System.InvalidOperationException: This operation is only valid on generic types.
at System.RuntimeType.GetGenericTypeDefinition()
at Namotion.Reflection.ContextualType.<get_Fields>b__36_0(FieldInfo field)
at System.Linq.Enumerable.SelectArrayIterator2.Fill(ReadOnlySpan1 source, Span1 destination, Func2 func)
at System.Linq.Enumerable.SelectArrayIterator2.ToArray() at Namotion.Reflection.ContextualType.get_Fields() at NJsonSchema.Generation.SystemTextJsonReflectionService.GenerateProperties(JsonSchema schema, ContextualType contextualType, SystemTextJsonSchemaGeneratorSettings settings, JsonSchemaGenerator schemaGenerator, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.ReflectionServiceBase1.NJsonSchema.Generation.IReflectionService.GenerateProperties(JsonSchema schema, ContextualType contextualType, JsonSchemaGeneratorSettings settings, JsonSchemaGenerator schemaGenerator, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.GenerateInheritance(ContextualType type, JsonSchema schema, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.GenerateObject(JsonSchema schema, JsonTypeDescription typeDescription, JsonSchemaResolver schemaResolver)
at NSwag.Generation.OpenApiSchemaGenerator.GenerateObject(JsonSchema schema, JsonTypeDescription typeDescription, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](TSchemaType schema, ContextualType contextualType, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](ContextualType contextualType, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](Type type, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.Generate(Type type, JsonSchemaResolver schemaResolver)
at NSwag.Generation.OpenApiSchemaGenerator.GenerateObject(JsonSchema schema, JsonTypeDescription typeDescription, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](TSchemaType schema, ContextualType contextualType, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](ContextualType contextualType, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.JsonSchemaGenerator.GenerateWithReferenceAndNullability[TSchemaType](ContextualType contextualType, Boolean isNullable, JsonSchemaResolver schemaResolver, Action2 transformation) at NSwag.Generation.OpenApiSchemaGenerator.GenerateWithReferenceAndNullability[TSchemaType](ContextualType contextualType, Boolean isNullable, JsonSchemaResolver schemaResolver, Action2 transformation)
at NJsonSchema.Generation.JsonSchemaGenerator.AddProperty(JsonSchema parentSchema, ContextualAccessorInfo property, JsonTypeDescription propertyTypeDescription, String propertyName, Attribute requiredAttribute, Boolean hasRequiredAttribute, Boolean isNullable, Object defaultValue, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.SystemTextJsonReflectionService.GenerateProperties(JsonSchema schema, ContextualType contextualType, SystemTextJsonSchemaGeneratorSettings settings, JsonSchemaGenerator schemaGenerator, JsonSchemaResolver schemaResolver)
at NJsonSchema.Generation.ReflectionServiceBase1.NJsonSchema.Generation.IReflectionService.GenerateProperties(JsonSchema schema, ContextualType contextualType, JsonSchemaGeneratorSettings settings, JsonSchemaGenerator schemaGenerator, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.GenerateObject(JsonSchema schema, JsonTypeDescription typeDescription, JsonSchemaResolver schemaResolver) at NSwag.Generation.OpenApiSchemaGenerator.GenerateObject(JsonSchema schema, JsonTypeDescription typeDescription, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](TSchemaType schema, ContextualType contextualType, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](ContextualType contextualType, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.GenerateWithReferenceAndNullability[TSchemaType](ContextualType contextualType, Boolean isNullable, JsonSchemaResolver schemaResolver, Action2 transformation)
at NSwag.Generation.OpenApiSchemaGenerator.GenerateWithReferenceAndNullability[TSchemaType](ContextualType contextualType, Boolean isNullable, JsonSchemaResolver schemaResolver, Action2 transformation) at NJsonSchema.Generation.JsonSchemaGenerator.GenerateArray[TSchemaType](TSchemaType schema, JsonTypeDescription typeDescription, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](TSchemaType schema, ContextualType contextualType, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.Generate[TSchemaType](ContextualType contextualType, JsonSchemaResolver schemaResolver) at NJsonSchema.Generation.JsonSchemaGenerator.GenerateWithReferenceAndNullability[TSchemaType](ContextualType contextualType, Boolean isNullable, JsonSchemaResolver schemaResolver, Action2 transformation)
at NSwag.Generation.OpenApiSchemaGenerator.GenerateWithReferenceAndNullability[TSchemaType](ContextualType contextualType, Boolean isNullable, JsonSchemaResolver schemaResolver, Action2 transformation) at NSwag.Generation.AspNetCore.Processors.OperationResponseProcessor.Process(OperationProcessorContext operationProcessorContext) at NSwag.Generation.AspNetCore.AspNetCoreOpenApiDocumentGenerator.RunOperationProcessors(OpenApiDocument document, ApiDescription apiDescription, Type controllerType, MethodInfo methodInfo, OpenApiOperationDescription operationDescription, List1 allOperations, OpenApiDocumentGenerator generator, OpenApiSchemaResolver schemaResolver)
at NSwag.Generation.AspNetCore.AspNetCoreOpenApiDocumentGenerator.AddOperationDescriptionsToDocument(OpenApiDocument document, Type controllerType, List1 operations, OpenApiDocumentGenerator swaggerGenerator, OpenApiSchemaResolver schemaResolver) at NSwag.Generation.AspNetCore.AspNetCoreOpenApiDocumentGenerator.GenerateApiGroups(OpenApiDocumentGenerator generator, OpenApiDocument document, IGrouping2[] apiGroups, OpenApiSchemaResolver schemaResolver)
at NSwag.Generation.AspNetCore.AspNetCoreOpenApiDocumentGenerator.GenerateAsync(ApiDescriptionGroupCollection apiDescriptionGroups)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()