[Instrumentation.AspNet] Fix multiple routes of same template in attribute-based routing

src/OpenTelemetry.Instrumentation.AspNet/Implementation/HttpRequestRouteHelper.cs

@@ -28,8 +28,11 @@ internal sealed class HttpRequestRouteHelper
         {
             // WebAPI attribute routing flows here. Use reflection to not take a dependency on microsoft.aspnet.webapi.core\[version]\lib\[framework]\System.Web.Http.
 
-            if (msSubRoutes is Array attributeRouting && attributeRouting.Length == 1)
+            if (msSubRoutes is Array attributeRouting && attributeRouting.Length >= 1)
             {
+                // There could be more than one subroute, each with a different method.
+                // But the template is the same across them, so we simply take the template
+                // from the first route.
                 var subRouteData = attributeRouting.GetValue(0);
 
                 _ = this.routeFetcher.TryFetch(subRouteData, out var route);

test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInListenerTests.cs

@@ -41,6 +41,7 @@ public enum QueryRedactionDisableBehavior
     [InlineData("https://localhost:443/about_attr_route/10", "https", "/about_attr_route/10", null, null, "localhost", 443, "HEAD", "HEAD", null, 2, "about_attr_route/{customerId}", "HEAD about_attr_route/{customerId}")]
     [InlineData("http://localhost:1880/api/weatherforecast", "http", "/api/weatherforecast", null, null, "localhost", 1880, "GET", "GET", null, 3, "api/{controller}/{id}", "GET api/{controller}/{id}")]
     [InlineData("https://localhost:1843/subroute/10", "https", "/subroute/10", null, null, "localhost", 1843, "GET", "GET", null, 4, "subroute/{customerId}", "GET subroute/{customerId}")]
+    [InlineData("https://localhost:1843/subroute/10", "https", "/subroute/10", null, null, "localhost", 1843, "GET", "GET", null, 5, "subroute/{customerId}", "GET subroute/{customerId}")]
     [InlineData("http://localhost/api/value", "http", "/api/value", null, null, "localhost", 80, "GET", "GET", null, 0, null, "GET", false, "/api/value")] // Request will be filtered
     [InlineData("http://localhost/api/value", "http", "/api/value", null, null, "localhost", 80, "GET", "GET", null, 0, null, "GET", false, "{ThrowException}")] // Filter user code will throw an exception
     [InlineData("http://localhost/", "http", "/", null, null, "localhost", 80, "GET", "GET", null, 0, null, "GET", false, null, true, "System.InvalidOperationException")] // Test RecordException option

test/OpenTelemetry.Instrumentation.AspNet.Tests/RouteTestHelper.cs

@@ -1,6 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
+using System.Net.Http;
 using System.Web;
 using System.Web.Routing;
 
@@ -40,6 +41,75 @@ public static HttpContext BuildHttpContext(string url, int routeType, string? ro
                     "MS_SubRoutes",
                     value);
                 break;
+            case 5: // Multi-method attribute routing WebAPI.
+                routeData = new RouteData();
+                var multiMethodSubroutes = new[]
+                {
+                    new
+                    {
+                        Route = new
+                        {
+                            RouteTemplate = routeTemplate,
+                            DataTokens = new Dictionary<string, object>
+                            {
+                                ["actions"] = new[]
+                                {
+                                    new
+                                    {
+                                        SupportedHttpMethods = new[]
+                                        {
+                                            HttpMethod.Get,
+                                        },
+                                    },
+                                },
+                            },
+                        },
+                    },
+                    new
+                    {
+                        Route = new
+                        {
+                            RouteTemplate = routeTemplate,
+                            DataTokens = new Dictionary<string, object>
+                            {
+                                ["actions"] = new[]
+                                {
+                                    new
+                                    {
+                                        SupportedHttpMethods = new[]
+                                        {
+                                            HttpMethod.Put,
+                                        },
+                                    },
+                                },
+                            },
+                        },
+                    },
+                    new
+                    {
+                        Route = new
+                        {
+                            RouteTemplate = routeTemplate,
+                            DataTokens = new Dictionary<string, object>
+                            {
+                                ["actions"] = new[]
+                                {
+                                    new
+                                    {
+                                        SupportedHttpMethods = new[]
+                                        {
+                                            HttpMethod.Delete,
+                                        },
+                                    },
+                                },
+                            },
+                        },
+                    },
+                };
+                routeData.Values.Add(
+                    "MS_SubRoutes",
+                    multiMethodSubroutes);
+                break;
             default:
                 throw new NotSupportedException();
         }