Various fixes recommended by analysis (#1498)

Author: JamesNK

src/Grpc.AspNetCore.Server/Internal/HttpContextStreamReader.cs

@@ -33,11 +33,7 @@ public HttpContextStreamReader(HttpContextServerCallContext serverCallContext, F
             _deserializer = deserializer;
         }
 
-        // IAsyncStreamReader<T> should declare Current as nullable
-        // Suppress warning when overriding interface definition
-#pragma warning disable CS8613, CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member.
-        public TRequest? Current { get; private set; }
-#pragma warning restore CS8613, CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member.
+        public TRequest Current { get; private set; } = default!;
 
         public void Dispose() { }
 
@@ -74,7 +70,7 @@ private bool ProcessPayload(TRequest? request)
             // Stream is complete
             if (request == null)
             {
-                Current = null;
+                Current = null!;
                 return false;
             }
 

src/Grpc.AspNetCore.Server/Model/Internal/ServiceRouteBuilder.cs

@@ -140,10 +140,8 @@ internal static void CreateUnimplementedEndpoints(
 
         private static IEndpointConventionBuilder CreateUnimplementedEndpoint(IEndpointRouteBuilder endpointRouteBuilder, string pattern, string displayName, RequestDelegate requestDelegate)
         {
-#pragma warning disable CS8625 // Cannot convert null literal to non-nullable reference type.
             // https://github.com/dotnet/aspnetcore/issues/24042
             var routePattern = RoutePatternFactory.Parse(pattern, defaults: null, new { contentType = GrpcUnimplementedConstraint.Instance });
-#pragma warning restore CS8625 // Cannot convert null literal to non-nullable reference type.
             var endpointBuilder = endpointRouteBuilder.Map(routePattern, requestDelegate);
 
             endpointBuilder.Add(ep =>

src/Grpc.Net.Client/Balancer/BalancerAttributes.cs

@@ -99,7 +99,7 @@ public bool TryGetValue<TValue>(BalancerAttributesKey<TValue> key, [MaybeNullWhe
                 return true;
             }
 
-            value = default(TValue);
+            value = default;
             return false;
         }
 

src/Grpc.Net.Client/Balancer/DnsResolver.cs

@@ -107,7 +107,12 @@ protected override async Task ResolveAsync(CancellationToken cancellationToken)
                 }
 
                 DnsResolverLog.StartingDnsQuery(_logger, _dnsAddress);
-                var addresses = await Dns.GetHostAddressesAsync(_dnsAddress).ConfigureAwait(false);
+                var addresses =
+#if NET6_0_OR_GREATER                    
+                    await Dns.GetHostAddressesAsync(_dnsAddress, cancellationToken).ConfigureAwait(false);
+#else
+                    await Dns.GetHostAddressesAsync(_dnsAddress).ConfigureAwait(false);
+#endif
 
                 DnsResolverLog.ReceivedDnsResults(_logger, addresses.Length, _dnsAddress, addresses);
 

src/Grpc.Net.Client/Balancer/Resolver.cs

@@ -48,7 +48,8 @@ namespace Grpc.Net.Client.Balancer
     /// </summary>
     public abstract class Resolver : IDisposable
     {
-        private Task _resolveTask = Task.CompletedTask;
+        // Internal for testing
+        internal Task _resolveTask = Task.CompletedTask;
         private Action<ResolverResult>? _listener;
         private bool _disposed;
 

src/Grpc.Net.Client/Internal/HttpContentClientStreamReader.cs

@@ -50,11 +50,7 @@ public HttpContentClientStreamReader(GrpcCall<TRequest, TResponse> call)
             HttpResponseTcs = new TaskCompletionSource<(HttpResponseMessage, Status?)>(TaskCreationOptions.RunContinuationsAsynchronously);
         }
 
-        // IAsyncStreamReader<T> should declare Current as nullable
-        // Suppress warning when overriding interface definition
-#pragma warning disable CS8613, CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member.
-        public TResponse? Current { get; private set; }
-#pragma warning restore CS8613, CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member.
+        public TResponse Current { get; private set; } = default!;
 
         public void Dispose()
         {
@@ -156,12 +152,13 @@ private async Task<bool> MoveNextCore(CancellationToken cancellationToken)
 
                 CompatibilityHelpers.Assert(_grpcEncoding != null, "Encoding should have been calculated from response.");
 
-                Current = await _call.ReadMessageAsync(
+                var readMessage = await _call.ReadMessageAsync(
                     _responseStream,
                     _grpcEncoding,
                     singleMessage: false,
                     _call.CancellationToken).ConfigureAwait(false);
-                if (Current == null)
+
+                if (readMessage == null)
                 {
                     // No more content in response so report status to call.
                     // The call will handle finishing the response.
@@ -172,10 +169,12 @@ private async Task<bool> MoveNextCore(CancellationToken cancellationToken)
                         throw _call.CreateFailureStatusException(status);
                     }
 
+                    Current = null!;
                     return false;
                 }
 
                 GrpcEventSource.Log.MessageReceived();
+                Current = readMessage!;
                 return true;
             }
             catch (OperationCanceledException ex)

test/FunctionalTests/Balancer/DnsResolverTests.cs

@@ -140,6 +140,8 @@ public async Task RefreshAsync_MultipleCalls_HitRateLimit()
             var result = await tcs.Task.DefaultTimeout();
             Assert.Greater(result.Addresses!.Count, 0);
 
+            // Wait for the internal resolve task to be completed before triggering refresh again
+            await dnsResolver._resolveTask.DefaultTimeout();
             tcs = new TaskCompletionSource<ResolverResult>(TaskCreationOptions.RunContinuationsAsynchronously);
             dnsResolver.Refresh();
 
@@ -179,6 +181,8 @@ public async Task RefreshAsync_MultipleCallsThenCancellation_CallCanceled()
             var result = await tcs.Task.DefaultTimeout();
             Assert.Greater(result.Addresses!.Count, 0);
 
+            // Wait for the internal resolve task to be completed before triggering refresh again
+            await dnsResolver._resolveTask.DefaultTimeout();
             tcs = new TaskCompletionSource<ResolverResult>(TaskCreationOptions.RunContinuationsAsynchronously);
             dnsResolver.Refresh();
 

test/FunctionalTests/Linker/LinkerTests.cs

@@ -83,7 +83,7 @@ public async Task RunWebsiteAndCallWithClient_Success()
             }
         }
 
-        private void EnsureDeleted(string path)
+        private static void EnsureDeleted(string path)
         {
             if (Directory.Exists(path))
             {

test/Grpc.AspNetCore.Server.Tests/Reflection/ReflectionGrpcServiceActivatorTests.cs

@@ -135,11 +135,7 @@ private class GreeterService : Greeter.GreeterBase
 
         private class TestAsyncStreamReader : IAsyncStreamReader<ServerReflectionRequest>
         {
-            // IAsyncStreamReader<T> should declare Current as nullable
-            // Suppress warning when overriding interface definition
-#pragma warning disable CS8613, CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member.
-            public ServerReflectionRequest? Current { get; set; }
-#pragma warning restore CS8613, CS8766 // Nullability of reference types in return type doesn't match implicitly implemented member.
+            public ServerReflectionRequest Current { get; set; } = default!;
             private bool _hasNext = true;
 
             public void Dispose()

test/Grpc.Net.Client.Tests/GrpcChannelTests.cs

@@ -680,7 +680,7 @@ public async Task ConnectAsync_ShiftThroughStates_CompleteOnReady()
             Assert.AreEqual(ConnectivityState.Shutdown, channel.State);
         }
 
-        private async Task WaitForStateAsync(GrpcChannel channel, ConnectivityState state)
+        private static async Task WaitForStateAsync(GrpcChannel channel, ConnectivityState state)
         {
             while (true)
             {