See comments on issue #3: Pending questions shall fail when connection is broken.

Adjusted required version of .NET Core runtime from 2.2 to 2.1

Capnp.Net.Runtime.Core21/Capnp.Net.Runtime.Core21.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.2</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

Capnp.Net.Runtime.Tests/TcpRpcAdvancedStuff.cs

@@ -10,7 +10,7 @@ using System.Threading.Tasks;
 namespace Capnp.Net.Runtime.Tests
 {
     [TestClass]
-    public class TcpRpcAdvancedStuff: TestBase
+    public class TcpRpcAdvancedStuff : TestBase
     {
         [TestMethod, Timeout(10000)]
         public void MultiConnect()
@@ -88,5 +88,37 @@ namespace Capnp.Net.Runtime.Tests
                 }
             }
         }
+
+        [TestMethod, Timeout(10000)]
+        public void ClosingServerWhileRequestingBootstrap()
+        {
+            for (int i = 0; i < 100; i++)
+            {
+                var server = SetupServer();
+                var counters = new Counters();
+                var tcs = new TaskCompletionSource<int>();
+                server.Main = new TestInterfaceImpl(counters, tcs);
+
+                using (var client = SetupClient())
+                {
+                    Assert.IsTrue(client.WhenConnected.Wait(MediumNonDbgTimeout));
+
+                    using (var main = client.GetMain<ITestInterface>())
+                    {
+                        server.Dispose();
+
+                        // Resolution must either succeed or be cancelled. A hanging resolution would be inacceptable.
+
+                        try
+                        {
+                            Assert.IsTrue(((IResolvingCapability)main).WhenResolved.Wait(MediumNonDbgTimeout));
+                        }
+                        catch (AggregateException)
+                        {
+                        }
+                    }
+                }
+            }
+        }
     }
 }

Capnp.Net.Runtime.Tests/TcpRpcInterop.cs

@@ -751,7 +751,19 @@ namespace Capnp.Net.Runtime.Tests
                     using (var main = client.GetMain<ITestMoreStuff>())
                     {
                         var resolving = main as IResolvingCapability;
-                        if (!resolving.WhenResolved.Wait(MediumNonDbgTimeout))
+
+                        bool success;
+
+                        try
+                        {
+                            success = resolving.WhenResolved.Wait(MediumNonDbgTimeout);
+                        }
+                        catch
+                        {
+                            success = false;
+                        }
+
+                        if (!success)
                         {
                             if (++retry == 5)
                             {
@@ -917,13 +929,24 @@ namespace Capnp.Net.Runtime.Tests
                 label:
                 using (var client = new TcpRpcClient("localhost", TcpPort))
                 {
-
                     Assert.IsTrue(client.WhenConnected.Wait(MediumNonDbgTimeout));
 
                     using (var main = client.GetMain<ITestMoreStuff>())
                     {
                         var resolving = main as IResolvingCapability;
-                        if (!resolving.WhenResolved.Wait(MediumNonDbgTimeout))
+
+                        bool success;
+
+                        try
+                        {
+                            success = resolving.WhenResolved.Wait(MediumNonDbgTimeout);
+                        }
+                        catch
+                        {
+                            success = false;
+                        }
+
+                        if (!success)
                         {
                             if (++retry == 5)
                             {

Capnp.Net.Runtime/Rpc/RpcEngine.cs

@@ -3,6 +3,7 @@ using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
@@ -97,7 +98,14 @@ namespace Capnp.Rpc
                 {
                     _exportTable.Clear();
                     _revExportTable.Clear();
-                    _questionTable.Clear();
+
+                    foreach (var question in _questionTable.Values.ToList())
+                    {
+                        question.OnException(new RpcException("RPC connection is broken. Task would never return."));
+                    }
+
+                    Debug.Assert(_questionTable.Count == 0);
+
                     _answerTable.Clear();
                     _pendingDisembargos.Clear();
                 }

Capnp.Net.Runtime/Rpc/Vine.cs

@@ -38,9 +38,15 @@ namespace Capnp.Rpc
             {
                 async void SetupCancellation()
                 {
-                    using (var registration = cancellationToken.Register(promisedAnswer.Dispose))
+                    try
+                    {
+                        using (var registration = cancellationToken.Register(promisedAnswer.Dispose))
+                        {
+                            await promisedAnswer.WhenReturned;
+                        }
+                    }
+                    catch
                     {
-                        await promisedAnswer.WhenReturned;
                     }
                 }