OData SDK v8.0.1 Creating Duplicate Routes

When the IServiceCollection.AddOData() extension method is called, conventional and attribute routes are added. When the path template specified on an [HttpMethod] attribute is the same as the path template generated by conventional routing, two routes for the same HTTP method and path template combination are created.

Example

The example below will generate two GET odata/Items routes.

[Route("odata")]
public class ItemsController : ODataController
{
    ...
    [HttpGet("Items")]
    public IActionResult GetItems()
    {
        ...
        return Ok(items);
    }
}

Reproduction Steps

> git clone git@github.com:donile/odata-duplicate-routes-example.git

> cd ./odata-duplicate-routes-example

> dotnet run --project .\src\ODataDuplicateRoutesExample\ODataDuplicateRoutesExample.csproj

HTTP GET https://localhost:5001/swagger/v1/swagger.json with your http client of choice. =)

Upon attempting to retrieve the OpenAPI schema, an HTTP response with status code 500 is returned, including the following error:

Swashbuckle.AspNetCore.SwaggerGen.SwaggerGeneratorException: Conflicting method/path combination "GET odata/Items" for actions - ODataDuplicateRoutesExample.Controllers.ItemsController.GetItems (ODataDuplicateRoutesExample),ODataDuplicateRoutesExample.Controllers.ItemsController.GetItems (ODataDuplicateRoutesExample). Actions require a unique method/path combination for Swagger/OpenAPI 3.0. Use ConflictingActionsResolver as a workaround
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperations(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePaths(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwagger(String documentName, String host, String basePath)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Offer to Help

I would like to help resolve the issue and submit a PR, but before I investigate further, I was hoping I could receive some guidance regarding acceptance criteria for this feature. Is this a bug or is the observed behavior expected? If it's not the expected behavior, what is the expected behavior? The way I see it, there are three options.

1. This is the expected behavior.
2. When an attribute route matches the conventional route, ignore the conventional route.
3. When an action method is decorated with an [HttpMethod], ignore the conventional route.
   3.1 When a controller is decorated with an [ODataAttributeRouting], do not generate conventional routes for any of the controller's action methods.