fix null ref on http conflict response in remote client

src/DurableTask.AzureServiceFabric/DurableTask.AzureServiceFabric.csproj

@@ -6,7 +6,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <PackageId>Microsoft.Azure.DurableTask.AzureServiceFabric</PackageId>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <Version>2.3.11</Version>
+    <Version>2.3.12</Version>
     <AssemblyVersion>$(Version)</AssemblyVersion>
     <FileVersion>$(Version)</FileVersion>
     <Title>Azure Service Fabric provider extension for the Durable Task Framework.</Title>

src/DurableTask.AzureServiceFabric/Remote/RemoteOrchestrationServiceClient.cs

@@ -317,12 +317,12 @@ private async Task PutJsonAsync(string instanceId, string fragment, object @obje
                 // TODO: Improve exception handling
                 if (result.StatusCode == HttpStatusCode.Conflict)
                 {
-                    throw await result.Content?.ReadAsAsync<OrchestrationAlreadyExistsException>();
+                    throw await (result.Content?.ReadAsAsync<OrchestrationAlreadyExistsException>() ?? Task.FromResult(new OrchestrationAlreadyExistsException()));
                 }
 
                 if (!result.IsSuccessStatusCode)
                 {
-                    var content = await result.Content?.ReadAsStringAsync();
+                    var content = await (result.Content?.ReadAsStringAsync() ?? Task.FromResult<string>(null));
                     throw new RemoteServiceException($"CreateTaskOrchestrationAsync failed with status code {result.StatusCode}: {content}", result.StatusCode);
                 }
             }

src/DurableTask.AzureServiceFabric/Service/FabricOrchestrationServiceController.cs

@@ -69,13 +69,13 @@ public async Task<IHttpActionResult> CreateTaskOrchestration([FromUri] string or
 
                 return new OkResult(this);
             }
-            catch (OrchestrationAlreadyExistsException ex)
+            catch (OrchestrationAlreadyExistsException orchestrationAlreadyExistsException)
             {
-                return Content<OrchestrationAlreadyExistsException>(System.Net.HttpStatusCode.Conflict, ex);
+                return Content<OrchestrationAlreadyExistsException>(System.Net.HttpStatusCode.Conflict, orchestrationAlreadyExistsException);
             }
-            catch (NotSupportedException ex)
+            catch (NotSupportedException notSupportedException)
             {
-                return Content<NotSupportedException>(System.Net.HttpStatusCode.BadRequest, ex);
+                return Content<NotSupportedException>(System.Net.HttpStatusCode.BadRequest, notSupportedException);
             }
         }
 

test/DurableTask.AzureServiceFabric.Integration.Tests/DurableTask.AzureServiceFabric.Integration.Tests.csproj

@@ -14,6 +14,7 @@
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />
     <PackageReference Include="Microsoft.AspNet.WebApi.Core" Version="5.2.6" />
+    <PackageReference Include="Moq" Version="4.10.0" />
   </ItemGroup>
 
   <ItemGroup>

test/DurableTask.AzureServiceFabric.Integration.Tests/FunctionalTests.cs

@@ -15,14 +15,15 @@ namespace DurableTask.AzureServiceFabric.Integration.Tests
 {
     using System;
     using System.Collections.Generic;
+    using System.Net.Http;
+    using System.Threading;
     using System.Threading.Tasks;
     using DurableTask.AzureServiceFabric.Exceptions;
     using DurableTask.Core;
     using DurableTask.Core.Exceptions;
     using DurableTask.Test.Orchestrations.Performance;
-
     using Microsoft.VisualStudio.TestTools.UnitTesting;
-
+    using Moq;
     using TestApplication.Common.Orchestrations;
 
     [TestClass]
@@ -586,5 +587,42 @@ public async Task ScheduledStartTest_NotSupported()
             var expectedStartTime = DateTime.UtcNow.AddSeconds(30);
             await Assert.ThrowsExceptionAsync<RemoteServiceException>(() => this.taskHubClient.CreateScheduledOrchestrationInstanceAsync(typeof(SimpleOrchestrationWithTasks), null, expectedStartTime));
         }
+
+        [TestMethod]
+        public async Task CreateTaskOrchestration_HandlesConflictResponse_When_HttpClientReturnsNullContent()
+        {
+            var httpClientMock = new Mock<HttpClient>();
+            var response = new HttpResponseMessage(System.Net.HttpStatusCode.Conflict) { Content = null };
+            SetupHttpClientMockForPut(httpClientMock, response);
+
+            var taskHubClient = Utilities.CreateTaskHubClient((serviceClient) =>
+            {
+                serviceClient.HttpClient = httpClientMock.Object;
+            });
+
+            await Assert.ThrowsExceptionAsync<OrchestrationAlreadyExistsException>(async () =>
+            {
+                await taskHubClient.CreateOrchestrationInstanceAsync(typeof(TestOrchestration), new TestOrchestrationData());
+            });
+        }
+
+        private static void SetupHttpClientMockForPut(Mock<HttpClient> httpClientMock, HttpResponseMessage response)
+        {
+            httpClientMock
+                .Setup(x => x.PutAsync(It.IsAny<string>(), It.IsAny<HttpContent>()))
+                .ReturnsAsync(response);
+
+            httpClientMock
+                .Setup(x => x.PutAsync(It.IsAny<Uri>(), It.IsAny<HttpContent>()))
+                .ReturnsAsync(response);
+
+            httpClientMock
+                .Setup(x => x.PutAsync(It.IsAny<string>(), It.IsAny<HttpContent>(), It.IsAny<CancellationToken>()))
+                .ReturnsAsync(response);
+
+            httpClientMock
+                .Setup(x => x.PutAsync(It.IsAny<Uri>(), It.IsAny<HttpContent>(), It.IsAny<CancellationToken>()))
+                .ReturnsAsync(response);
+        }
     }
 }

test/DurableTask.AzureServiceFabric.Integration.Tests/Utilities.cs

@@ -17,22 +17,27 @@ namespace DurableTask.AzureServiceFabric.Integration.Tests
     using System.Diagnostics;
     using System.Net.Http;
     using System.Threading.Tasks;
-    using DurableTask.Core;
     using DurableTask.AzureServiceFabric.Remote;
-    using DurableTask.AzureServiceFabric.Service;
-
+    using DurableTask.Core;
     using Microsoft.VisualStudio.TestTools.UnitTesting;
 
     public static class Utilities
     {
         public static TaskHubClient CreateTaskHubClient()
+        {
+            return CreateTaskHubClient(_ => { });
+        }
+
+        public static TaskHubClient CreateTaskHubClient(Action<RemoteOrchestrationServiceClient> setupServiceClient)
         {
             var partitionProvider = new FabricPartitionEndpointResolver(new Uri(Constants.TestFabricApplicationAddress), new DefaultStringPartitionHashing());
             var httpClientHandler = new HttpClientHandler()
             {
                 ServerCertificateCustomValidationCallback = (message, certificate, chain, errors) => true
             };
-            return new TaskHubClient(new RemoteOrchestrationServiceClient(partitionProvider, httpClientHandler));
+            var serviceClient = new RemoteOrchestrationServiceClient(partitionProvider, httpClientHandler);
+            setupServiceClient(serviceClient);
+            return new TaskHubClient(serviceClient);
         }
 
         public static async Task ThrowsException<TException>(Func<Task> action, string expectedMessage) where TException : Exception