API version with status property returns 404 when called

[marcominerva]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm using UrlSegmentApiVersionReader. If I create an API version with a status property, I get a 404 error when I try to call it (either from Swagger or directly from the browser).

Expected Behavior

The versioned API with the status label should be called as expected.

Steps To Reproduce

#!/usr/bin/env dotnet

#:sdk Microsoft.NET.Sdk.Web

#:property TargetFramework=net10.0
#:property Nullable=enable
#:property ImplicitUsings=enable
#:property PublishAot=false

#:package Asp.Versioning.Http@10.0.0
#:package Asp.Versioning.Mvc.ApiExplorer@10.0.0
#:package Asp.Versioning.OpenApi@10.0.0-rc.1
#:package Microsoft.AspNetCore.OpenApi@10.0.8
#:package Swashbuckle.AspNetCore.SwaggerUI@10.1.7

using Asp.Versioning;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddApiVersioning(options =>
{
    options.ApiVersionReader = new UrlSegmentApiVersionReader();

}).AddApiExplorer(options =>
{
    options.GroupNameFormat = "'v'VVV";
    options.SubstituteApiVersionInUrl = true;
})
.AddOpenApi();

var app = builder.Build();

app.UseHttpsRedirection();

app.MapOpenApi().WithDocumentPerVersion();

var versionedApi = app.NewVersionedApi().ReportApiVersions();

var v1Api = versionedApi.MapGroup("/api/v{version:apiVersion}").HasApiVersion(1);
var v2Api = versionedApi.MapGroup("/api/v{version:apiVersion}").HasApiVersion(2, "preview");

v1Api.MapGet("ping", () =>
{
    return TypedResults.Ok();
});

v2Api.MapGet("ping", () =>
{
    // It is never called: GET /api/v2-preview/ping returns 404.
    return TypedResults.Ok();
});

app.UseSwaggerUI(options =>
{
    var descriptions = app.DescribeApiVersions();

    foreach (var description in descriptions)
    {
        options.SwaggerEndpoint($"/openapi/{description.GroupName}.json", description.GroupName);
    }
});

app.Run();

.NET Version

.NET 10.0.8

Anything else?

Asp.Versioning.Http version 10.0.0
Asp.Versioning.Mvc.ApiExplorer version 10.0.0
Asp.Versioning.OpenApi version 10.0.0-rc.1

Visual Studio 2026 18.6.1

[commonsensesoftware]

Extracting the API version from a request when you version by URL segment uses the TemplateMatcher, which under the hood uses the RoutePatternMatcher. For some reason, the pattern is failing to match when the segment contains a literal - in it. I'm not sure why - yet. The constraint has no problem parsing the value, but it's not even reaching that point.

This issue has likely been quietly hiding for years now. 😞 It's one more issue with routing by URL segment. There should be some way to make it work.