Remove AddSingletonIfNotExists and call TryAddSingleton to fix bugs when keyed services are registered.

Author: CodeBlanch

NETCORE/src/Shared/Extensions/ApplicationInsightsExtensions.cs

@@ -280,26 +280,6 @@ internal static void AddTelemetryConfiguration(
             }
         }
 
-        /// <summary>
-        /// The AddSingleton method will not check if a class has already been added as an ImplementationType.
-        /// This extension method is to encapsulate those checks.
-        /// </summary>
-        /// <remarks>
-        /// Must check all three properties to avoid duplicates or null ref exceptions.
-        /// </remarks>
-        /// <typeparam name="TService">The type of the service to add.</typeparam>
-        /// <typeparam name="TImplementation">The type of the implementation to use.</typeparam>
-        /// <param name="services">The Microsoft.Extensions.DependencyInjection.IServiceCollection to add the service to.</param>
-        internal static void AddSingletonIfNotExists<TService, TImplementation>(this IServiceCollection services)
-            where TService : class
-            where TImplementation : class, TService
-        {
-            if (!services.Any(o => o.ImplementationFactory == null && typeof(TImplementation).IsAssignableFrom(o.ImplementationType ?? o.ImplementationInstance.GetType())))
-            {
-                services.AddSingleton<TService, TImplementation>();
-            }
-        }
-
         private static bool TryGetValue(this IConfiguration config, string primaryKey, out string value, string backupKey = null)
         {
             value = config[primaryKey];
@@ -332,7 +312,7 @@ private static void AddCommonInitializers(IServiceCollection services)
         private static void AddCommonTelemetryModules(IServiceCollection services)
         {
             // Previously users were encouraged to manually add the DiagnosticsTelemetryModule.
-            services.AddSingletonIfNotExists<ITelemetryModule, DiagnosticsTelemetryModule>();
+            services.TryAddSingleton<ITelemetryModule, DiagnosticsTelemetryModule>();
 
             // These modules add properties to Heartbeat and expect the DiagnosticsTelemetryModule to be configured in DI.
             services.AddSingleton<ITelemetryModule, AppServicesHeartbeatTelemetryModule>();