AmbiguousMatchException when using "{controller}.aspx" route template

[andriysavin]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have an MVC app with these conrollers among others:

• LoginController
• VaildateElectronicSignatureController
• ValidateLoginController

Each of them has an action method with the same signature: IActionResult ValidateLogin().
It also has the following route mapping:

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}.aspx/{action=Index}/{id?}");

Note that the only difference from the default route template is the ".aspx" suffix after "{controller=Home}".

Now, if I navigate to URI "/Login.aspx/ValidateLogin" with this app, I'm getting an AmbiguousMatchException:

Here, the ambiguity is between the aforementioned conrollers. This looks like absolute nonsense to me, as the {controller} token should receive the "Login" value, and then controller classes with LoginController name should be looked for. However, VaildateElectronicSignatureController, for example, has nothing from the captured controller name at all. It looks like matching is done only by action name, so all controllers with that action method do match.

If I remove the ".aspx" suffix from the routing pattern ("{controller=Home}/{action=Index}/{id?}") and the URI ("/Login/ValidateLogin") the error disappears.

I'm attaching a basic app to reproduce the error.

Expected Behavior

The {controller=Home}.aspx/{action=Index}/{id?} route template should work similarly to default {controller=Home}/{action=Index}/{id?} and cause no abiguity with controllers which don't even match the name.

Steps To Reproduce

https://github.com/andriysavin/bugreports/tree/main/RouteTemplateWithAspxBug

Exceptions (if any)

Microsoft.AspNetCore.Routing.Matching.AmbiguousMatchException: The request matched multiple endpoints. Matches:

WebApplication4.Controllers.LoginController.ValidateLogin (WebApplication4)
WebApplication4.Controllers.VaildateElectronicSignatureController.ValidateLogin (WebApplication4)
WebApplication4.Controllers.ValidateLoginController.ValidateLogin (WebApplication4)
at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ReportAmbiguity(CandidateState[] candidateState)
at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ProcessFinalCandidates(HttpContext httpContext, CandidateState[] candidateState)
at Microsoft.AspNetCore.Routing.Matching.DfaMatcher.MatchAsync(HttpContext httpContext)
at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

.NET Version

7.0.302

Anything else?

No response

[javiercn]

@andriysavin thanks for contacting us.

This likely has to do with the fact that the suffix in {controller=Home}.aspx is turning the route into a complex segment and that might have an impact in how we are processing it.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[andriysavin]

@javiercn thanks. To give more context, I'm facing this issue while doing migration of ASP.NET Framework application to ASP.NET Core. So it looks like it worked ok in the old MVC, and working weird in Core.