Threading analyzer

src/AutoDialer.cs

@@ -78,6 +78,7 @@ public void Dispose()
         /// </remarks>
         public int MinConnections { get; set; } = DefaultMinConnections;
 
+#pragma warning disable VSTHRD100 // Avoid async void methods
         /// <summary>
         ///   Called when the swarm has a new peer.
         /// </summary>
@@ -91,31 +92,30 @@ public void Dispose()
         ///   If the <see cref="MinConnections"/> is not reached, then the
         ///   <paramref name="peer"/> is dialed.
         /// </remarks>
-        void OnPeerDiscovered(object sender, Peer peer)
+        async void OnPeerDiscovered(object sender, Peer peer)
+#pragma warning restore VSTHRD100 // Avoid async void methods
         {
             var n = swarm.Manager.Connections.Count() + pendingConnects;
             if (swarm.IsRunning && n < MinConnections)
             {
                 Interlocked.Increment(ref pendingConnects);
-                Task.Run(async () =>
+                log.Debug($"Dialing new {peer}");
+                try
+                {
+                    await swarm.ConnectAsync(peer).ConfigureAwait(false);
+                }
+                catch(Exception)
                 {
-                    log.Debug($"Dialing new {peer}");
-                    try
-                    {
-                        await swarm.ConnectAsync(peer).ConfigureAwait(false);
-                    }
-                    catch(Exception)
-                    {
-                        log.Warn($"Failed to dial {peer}");
-                    }
-                    finally
-                    {
-                        Interlocked.Decrement(ref pendingConnects);
-                    }
-                });
+                    log.Warn($"Failed to dial {peer}");
+                }
+                finally
+                {
+                    Interlocked.Decrement(ref pendingConnects);
+                }
             }
         }
 
+#pragma warning disable VSTHRD100 // Avoid async void methods
         /// <summary>
         ///   Called when the swarm has lost a connection to a peer.
         /// </summary>
@@ -129,7 +129,8 @@ void OnPeerDiscovered(object sender, Peer peer)
         ///   If the <see cref="MinConnections"/> is not reached, then another
         ///   peer is dialed.
         /// </remarks>
-        void OnPeerDisconnected(object sender, Peer disconnectedPeer)
+        async void OnPeerDisconnected(object sender, Peer disconnectedPeer)
+#pragma warning restore VSTHRD100 // Avoid async void methods
         {
             var n = swarm.Manager.Connections.Count() + pendingConnects;
             if (!swarm.IsRunning || n >= MinConnections)
@@ -146,22 +147,19 @@ void OnPeerDisconnected(object sender, Peer disconnectedPeer)
             var peer = peers[rng.Next(peers.Count())];
 
             Interlocked.Increment(ref pendingConnects);
-            Task.Run(async () =>
+            log.Debug($"Dialing {peer}");
+            try
             {
-                log.Debug($"Dialing {peer}");
-                try
-                {
-                    await swarm.ConnectAsync(peer).ConfigureAwait(false);
-                }
-                catch (Exception)
-                {
-                    log.Warn($"Failed to dial {peer}");
-                }
-                finally
-                {
-                    Interlocked.Decrement(ref pendingConnects);
-                }
-            });
+                await swarm.ConnectAsync(peer).ConfigureAwait(false);
+            }
+            catch (Exception)
+            {
+                log.Warn($"Failed to dial {peer}");
+            }
+            finally
+            {
+                Interlocked.Decrement(ref pendingConnects);
+            }
         }
 
     }

src/Multiplex/Substream.cs

@@ -125,7 +125,9 @@ public void NoMoreData()
         /// <inheritdoc />
         public override int Read(byte[] buffer, int offset, int count)
         {
+#pragma warning disable VSTHRD002 
             return ReadAsync(buffer, offset, count).GetAwaiter().GetResult();
+#pragma warning restore VSTHRD002 
         }
 
         /// <inheritdoc />
@@ -164,7 +166,9 @@ public override async Task<int> ReadAsync(byte[] buffer, int offset, int count,
         /// <inheritdoc />
         public override void Flush()
         {
+#pragma warning disable VSTHRD002 
             FlushAsync().GetAwaiter().GetResult();
+#pragma warning restore VSTHRD002 
         }
 
         /// <inheritdoc />

src/PeerConnection.cs

@@ -217,10 +217,10 @@ public async Task InitiateAsync(
                 Initiator = true,
                 Connection = this
             };
-            muxer.SubstreamCreated += (s, e) => ReadMessages(e, CancellationToken.None);
+            muxer.SubstreamCreated += (s, e) => _ = ReadMessagesAsync(e, CancellationToken.None);
             this.MuxerEstablished.SetResult(muxer);
 
-            var _ = muxer.ProcessRequestsAsync();
+            _ = muxer.ProcessRequestsAsync();
         }
 
         /// <summary>
@@ -267,7 +267,7 @@ public Task EstablishProtocolAsync(string name, CancellationToken cancel)
         /// <summary>
         ///   Starts reading messages from the remote peer.
         /// </summary>
-        public async void ReadMessages(CancellationToken cancel)
+        public async Task ReadMessagesAsync(CancellationToken cancel)
         {
             log.Debug($"start reading messsages from {RemoteAddress}");
 
@@ -310,7 +310,7 @@ public async void ReadMessages(CancellationToken cancel)
         /// <summary>
         ///   Starts reading messages from the remote peer on the specified stream.
         /// </summary>
-        public async void ReadMessages(Stream stream, CancellationToken cancel)
+        public async Task ReadMessagesAsync(Stream stream, CancellationToken cancel)
         {
             IPeerProtocol protocol = new Multistream1();
             try

src/PeerManager.cs

@@ -55,12 +55,8 @@ public Task StartAsync()
             Swarm.ConnectionEstablished += Swarm_ConnectionEstablished;
             Swarm.PeerNotReachable += Swarm_PeerNotReachable;
 
-            var thread = new Thread(Phoenix)
-            {
-                IsBackground = true
-            };
             cancel = new CancellationTokenSource();
-            thread.Start();
+            var _ = PhoenixAsync(cancel.Token);
 
             log.Debug("started");
             return Task.CompletedTask;
@@ -145,9 +141,9 @@ void Swarm_ConnectionEstablished(object sender, PeerConnection connection)
         /// <summary>
         ///   Background process to try reconnecting to a dead peer.
         /// </summary>
-        async void Phoenix()
+        async Task PhoenixAsync(CancellationToken cancellation)
         {
-            while (!cancel.IsCancellationRequested)
+            while (!cancellation.IsCancellationRequested)
             {
                 try
                 {

src/PeerTalk.csproj

@@ -6,6 +6,7 @@
     <RootNamespace>PeerTalk</RootNamespace>
     <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
     <DebugType>portable</DebugType>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
 
     <!-- developer build is always 0.42 -->
     <AssemblyVersion>0.42</AssemblyVersion>
@@ -59,10 +60,12 @@
     <PackageReference Include="semver" Version="2.0.4" />
     <PackageReference Include="System.Threading.Tasks.Dataflow" Version="4.9.0" />
     <PackageReference Include="Portable.BouncyCastle" Version="1.8.5" />
-    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-19270-01">
-      <PrivateAssets>all</PrivateAssets>
-    </PackageReference>
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-19270-01" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="16.3.13" PrivateAssets="All" />
+  </ItemGroup>
+
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard14'">
     <PackageReference Include="System.Net.NameResolution" Version="4.3.0.0" />
   </ItemGroup>

src/Protocols/Identify1.cs

@@ -65,7 +65,7 @@ public override string ToString()
         /// </param>
         /// <param name="cancel"></param>
         /// <returns></returns>
-        public async Task<Peer> GetRemotePeer(PeerConnection connection, CancellationToken cancel)
+        public async Task<Peer> GetRemotePeerAsync(PeerConnection connection, CancellationToken cancel)
         {
             var muxer = await connection.MuxerEstablished.Task.ConfigureAwait(false);
             log.Debug("Get remote identity");

src/Protocols/Mplex67.cs

@@ -42,7 +42,7 @@ public override string ToString()
                 Connection = connection,
                 Receiver = true
             };
-            muxer.SubstreamCreated += (s, e) => connection.ReadMessages(e, CancellationToken.None);
+            muxer.SubstreamCreated += (s, e) => _ = connection.ReadMessagesAsync(e, CancellationToken.None);
 
             // Attach muxer to the connection.  It now becomes the message reader.
             connection.MuxerEstablished.SetResult(muxer);

src/PubSub/FloodRouter.cs

@@ -240,6 +240,7 @@ async Task SendAsync(byte[] message, Peer peer, CancellationToken cancel)
             }
         }
 
+#pragma warning disable VSTHRD100 // Avoid async void methods
         /// <summary>
         ///   Raised when a connection is established to a remote peer.
         /// </summary>
@@ -250,6 +251,7 @@ async Task SendAsync(byte[] message, Peer peer, CancellationToken cancel)
         ///   all topics that are of interest to the local peer.
         /// </remarks>
         async void Swarm_ConnectionEstablished(object sender, PeerConnection connection)
+#pragma warning restore VSTHRD100 // Avoid async void methods
         {
             if (localTopics.Count == 0)
                 return;

src/PubSub/NotificationService.cs

@@ -159,7 +159,9 @@ public PublishedMessage CreateMessage(string topic, byte[] data)
         {
             using (var ms = new MemoryStream())
             {
+#pragma warning disable VSTHRD103
                 message.CopyTo(ms);
+#pragma warning disable VSTHRD103 
                 return PublishAsync(topic, ms.ToArray(), cancel);
             }
         }
@@ -178,6 +180,9 @@ public async Task SubscribeAsync(string topic, Action<IPublishedMessage> handler
         {
             var topicHandler = new TopicHandler { Topic = topic, Handler = handler };
             topicHandlers.Add(topicHandler);
+
+            // TODO: need a better way.
+#pragma warning disable VSTHRD101 
             cancellationToken.Register(async () =>
             {
                 topicHandlers.Remove(topicHandler);
@@ -186,6 +191,7 @@ public async Task SubscribeAsync(string topic, Action<IPublishedMessage> handler
                     await Task.WhenAll(Routers.Select(r => r.LeaveTopicAsync(topic, CancellationToken.None))).ConfigureAwait(false);
                 }
             });
+#pragma warning restore VSTHRD101 
 
             // Tell routers if first time.
             if (topicHandlers.Count(t => t.Topic == topic) == 1)
@@ -233,7 +239,7 @@ void Router_MessageReceived(object sender, PublishedMessage msg)
             }
 
             // Tell other message routers.
-            Task.WhenAll(Routers
+            _ = Task.WhenAll(Routers
                 .Where(r => r != sender)
                 .Select(r => r.PublishAsync(msg, CancellationToken.None))
             );

src/Routing/Dht1.cs

@@ -250,7 +250,7 @@ public async Task<IEnumerable<Peer>> FindProvidersAsync(
         /// </remarks>
         public void Advertise(Cid cid)
         {
-            Task.Run(async () =>
+            _ = Task.Run(async () =>
             {
                 int advertsNeeded = 4;
                 var message = new DhtMessage
@@ -278,7 +278,7 @@ public void Advertise(Cid cid)
                         using (var stream = await Swarm.DialAsync(peer, this.ToString()))
                         {
                             ProtoBuf.Serializer.SerializeWithLengthPrefix(stream, message, PrefixStyle.Base128);
-                            stream.Flush();
+                            await stream.FlushAsync();
                         }
                         if (--advertsNeeded == 0)
                             break;

src/SecureCommunication/Secio1.cs

@@ -41,6 +41,7 @@ public override string ToString()
             await EncryptAsync(connection, cancel).ConfigureAwait(false);
         }
 
+#pragma warning disable VSTHRD103 
         /// <inheritdoc />
         public async Task<Stream> EncryptAsync(PeerConnection connection, CancellationToken cancel = default(CancellationToken))
         {

src/SecureCommunication/Secio1Stream.cs

@@ -121,7 +121,9 @@ public override void SetLength(long value)
         /// <inheritdoc />
         public override int Read(byte[] buffer, int offset, int count)
         {
+#pragma warning disable VSTHRD002 
             return ReadAsync(buffer, offset, count).GetAwaiter().GetResult();
+#pragma warning restore VSTHRD002 
         }
 
         /// <inheritdoc />
@@ -202,7 +204,9 @@ async Task<byte[]> ReadPacketBytesAsync(int count, CancellationToken cancel)
         /// <inheritdoc />
         public override void Flush()
         {
+#pragma warning disable VSTHRD002 
             FlushAsync().GetAwaiter().GetResult();
+#pragma warning restore VSTHRD002 
         }
 
         /// <inheritdoc />
@@ -225,8 +229,8 @@ public override async Task FlushAsync(CancellationToken cancel)
             stream.WriteByte((byte)(length >> 16));
             stream.WriteByte((byte)(length >> 8));
             stream.WriteByte((byte)(length));
-            stream.Write(data, 0, data.Length);
-            stream.Write(mac, 0, mac.Length);
+            await stream.WriteAsync(data, 0, data.Length);
+            await stream.WriteAsync(mac, 0, mac.Length);
             await stream.FlushAsync(cancel).ConfigureAwait(false);
 
             outStream.SetLength(0);

src/StatsStream.cs

@@ -30,7 +30,7 @@ public class StatsStream : Stream
 
         static StatsStream()
         {
-            Task.Run(async () =>
+            _ = Task.Run(async () =>
             {
                 while (true)
                 {