Improve reporting for duplicate route names in minimal APIs

[captainsafia]

Currently, if you have the following application in minimal APIs:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.MapGet("/", () => "Hello World!");
SomeComponent(app);
void SomeComponent(IEndpointRouteBuilder app)
{
app.MapGet("/", (string name) => $"Hello there {name}");
}
app.Run();

You will get the following stacktrace:

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
An unhandled exception has occurred while executing the request.
Microsoft.AspNetCore.Routing.Matching.AmbiguousMatchException: The request matched multiple endpoints. Matches:



/ HTTP: GET
/ HTTP: GET
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.DefaultEndpointSelector.Select(HttpContext httpContext, CandidateState[] candidateState)
at Microsoft.AspNetCore.Routing.Matching.DfaMatcher.MatchAsync(HttpContext httpContext)
at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Which is not helpful because we use the route pattern as the display name in our exceptions.

We need to figure out a way to provide a display name with more data to the user:

• The name of the delegate associated with the endpoint if possible
• The lambda signature
• The lambda