Correct Endpoint ignored by EndpointRoutingMiddleware

[serenata-keith-mifsud]

Describe the bug

In UseEndpoints, I have a custom MapBlog and mvc route mappings

The MapBlog maps blog/{**slug} to a new IApplicationBuilder which uses a proxy middleware.

Some of the route mappings contain multiple constraints, and this somehow removes blog/{**slug} from consideration.

Example of this: {a:regex(^defaultValue$}/{b:regex(^defaultValue$}

In reality the endpoints in my project are more complex than this, but this is enough to reproduce

To Reproduce

https://github.com/serenata-keith-mifsud/AspNetCore3.1RoutingIssue

static async Task EmptyResponse(HttpContext context)
            {
                await context.Response.WriteAsync($"Hello World from {context.GetEndpoint().DisplayName}!");
            }

app.UseEndpoints(endpoints =>
            {
                endpoints.Map("blog/{**blog}", endpoints.CreateApplicationBuilder().Use(next => EmptyResponse).Build()).WithDisplayName("Blog");
                endpoints.MapControllerRoute("HomePage", "/", new { controller = "Home", action = "Index" }).WithDisplayName("HomePage");
                endpoints.MapControllerRoute("TwoConstraints", "{a:regex(^a$)}/{b:regex(^b$)}", new { controller = "Home", action = "Index" }).WithDisplayName("TwoConstaints");
            });

Microsoft.AspNetCore.Routing.Matching.DfaMatcher: Debug: 1 candidate(s) found for the request path '/blog/post'
Microsoft.AspNetCore.Routing.Matching.DfaMatcher: Debug: Endpoint 'TwoConstaints' with route pattern '{a:regex(^a$)}/{b:regex(^b$)}' was rejected by constraint 'a':'Microsoft.AspNetCore.Routing.Constraints.RegexInlineRouteConstraint' with value 'blog' for the request path '/blog/post'
Microsoft.AspNetCore.Routing.Matching.DfaMatcher: Debug: Endpoint 'TwoConstaints' with route pattern '{a:regex(^a$)}/{b:regex(^b$)}' is not valid for the request path '/blog/post'
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware: Debug: Request did not match any endpoints

Further technical details

Runtime Environment:
OS Name: Windows
OS Version: 10.0.18362
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\3.1.100\

Host (useful for support):
Version: 3.1.0
Commit: 65f04fb6db

.NET Core SDKs installed:
2.0.2 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.509 [C:\Program Files\dotnet\sdk]
2.1.802 [C:\Program Files\dotnet\sdk]
2.2.402 [C:\Program Files\dotnet\sdk]
3.0.100 [C:\Program Files\dotnet\sdk]
3.1.100 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

IDE: Microsoft Visual Studio Professional 2019 Version 16.4.0

[pranavkm]

@rynowak \ @JamesNK would you like to have a look? I can reproduce the behavior but I got lost in the weeds in the DFA

[mlaily]

Hello,

Any news on this issue?

I think I hit the same (or a very similar) problem when trying to upgrade from .NET Core 2.1 to 3.1.

I have a controller with two routes, one with a regex:

[Route(@"{year:regex(^\d{{4}}$)}/{month:regex(^\d{{2}}$)}/{day:regex(^\d{{2}}$)}/{name}")]
[Route(@"{name}")]
public async Task<IActionResult> TestAsync(PostOrPageRouteData postOrPageRouteData)
...

And another controller with one route, with a catch-all:

[Route("comments/{*url}")]
public async Task<IActionResult> TestAsync(string url)
...

This route (with the catch-all) is never matched.

• If I remove the catch-all ({url} instead of {*url}), it works.
• If I use UseMvc() instead of UseEndpoints(), it works.
• If I remove the route with the regex, it works.

I made my own repro here https://github.com/mlaily/-EndpointRoutingRegexIssue

Is this expected? Is there a workaround, or should I avoid endpoint routing for now?

[serenata-keith-mifsud]

sorry, i didnt mean to close this.

[serenata-keith-mifsud]

Hi, will this be addressed in 3.1? or will we have to wait for 5.0 for endpoints to be usable?