Unobserved exception handling

CHANGELOG.md

@@ -5,10 +5,14 @@ Changelog
 
 ### Bug fixes
 
-* Handle any exceptions raised when reading files for code segments 
+* Handle any exceptions raised when reading files for code segments.
   | [twometresteve](https://github.com/twometresteve)
   | [#123](https://github.com/bugsnag/bugsnag-dotnet/pull/123)
 
+* Account for process termination behavior when handling UnobservedTaskExceptions.
+  | [twometresteve](https://github.com/twometresteve)
+  | [#125](https://github.com/bugsnag/bugsnag-dotnet/pull/125)
+
 ## 2.2.0 (2018-07-19)
 
 ### Enhancements

src/Bugsnag/Bugsnag.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <PackageId>Bugsnag</PackageId>
     <Title>Bugsnag .NET Notifier</Title>
@@ -19,6 +19,8 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Runtime.Serialization" />
+    <Reference Include="System.Xml" />
+    <Reference Include="System.Xml.Linq" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard1.3'">
     <PackageReference Include="System.Reflection.TypeExtensions" Version="4.3.0" />

src/Bugsnag/UnhandledException.cs

@@ -11,9 +11,11 @@ class UnhandledException
 
     private readonly object _currentClientLock = new object();
     private IClient _currentClient;
+    private bool _unobservedTerminates;
 
     private UnhandledException()
     {
+      _unobservedTerminates = DetermineUnobservedTerminates();
       AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
       AppDomain.CurrentDomain.ProcessExit += CurrentDomain_ProcessExit;
       TaskScheduler.UnobservedTaskException += TaskScheduler_UnobservedTaskException;
@@ -46,14 +48,34 @@ public void ConfigureClient(IClient client, IConfiguration configuration)
       }
     }
 
+    /// <summary>
+    /// Determines if an UnobservedTaskException leads to the process terminating, based on the target
+    /// framework and (when applicable) configuration.
+    /// </summary>
+    /// <returns></returns>
+    private bool DetermineUnobservedTerminates()
+    {
+#if NET35 || NET40
+      return true;
+#elif NET45
+      System.Xml.Linq.XElement configFile = System.Xml.Linq.XElement.Load(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);
+      var configValue = configFile?.Element("runtime")?.Element("ThrowUnobservedTaskExceptions")?.Attribute("enabled")?.Value;
+      bool value;
+      var success = bool.TryParse(configValue, out value);
+      return success && value;
+#else //NETSTANDARD1_3 || NETSTANDARD2_0
+      return false;
+#endif
+    }
+
     private void CurrentDomain_ProcessExit(object sender, EventArgs e)
     {
       HandleEvent(null, true);
     }
 
     private void TaskScheduler_UnobservedTaskException(object sender, UnobservedTaskExceptionEventArgs e)
     {
-      HandleEvent(e.Exception as Exception, !e.Observed);
+      HandleEvent(e.Exception as Exception, _unobservedTerminates && !e.Observed);
     }
 
     [HandleProcessCorruptedStateExceptions]