Fix for inline execution behavior of custom error handling actions. Closes GH-2023

Author: jeremydmiller

src/Testing/CoreTests/Bugs/Bug_2023_invoke_with_discard_error_handling.cs

@@ -0,0 +1,55 @@
+using Microsoft.Extensions.Hosting;
+using Wolverine.ErrorHandling;
+using Xunit;
+
+namespace CoreTests.Bugs;
+
+public class Bug_2023_invoke_with_discard_error_handling
+{
+    [Fact]
+    public async Task should_throw_the_exception_from_invoke()
+    {
+        using var host = await Host.CreateDefaultBuilder()
+            .UseWolverine(opts =>
+            {
+                // By default, this should NOT apply to inline executions (e.g. InvokeAsync),
+                // and an exception inside an inline execution should simply be surfaced.
+                // However, as of 3.13.0, this configuration causes the error not to be thrown.
+                opts.OnAnyException()
+                    .Discard()
+                    .And((runtime, context, ex) => {
+                        // Do some application-specific error handling here...
+                        return new ValueTask();
+                    });
+            }).StartAsync();
+
+        var bus = host.MessageBus();
+
+        await Should.ThrowAsync<Exception>(async () =>
+        {
+            await bus.InvokeAsync(new Request());
+        });
+        
+        
+    }
+}
+
+public class RequestHandler {
+/*
+    This is the exception that should appear to the user, but it does not.
+    This should not be caught by the Wolverine error handling because according
+    to the documentation,
+
+        `When using IMessageBus.InvokeAsync() to execute a message inline,
+        only the `Retry` and `Retry With Cooldown` error policies are applied
+        to the execution automatically.`
+
+    So, the `Discard/And` error policies should NOT be applied automatically,
+    and the error should be thrown (which was the case in 3.9.1, and got broken
+    by a commit in 3.13.0).
+*/
+    public string Handle(Request request) 
+        => throw new Exception(@"User-facing error message that should appear to the user.");
+}
+
+public class Request { }

src/Testing/CoreTests/ErrorHandling/LambdaContinuationTests.cs

@@ -21,10 +21,13 @@ public async Task execute_as_inline_with_no_invoke_usage()
             return new ValueTask();
         }, new Exception());
 
-        var result = await continuation.ExecuteInlineAsync(Substitute.For<IEnvelopeLifecycle>(),
-            new MockWolverineRuntime(), DateTimeOffset.UtcNow, null, CancellationToken.None);
-        
-        result.ShouldBe(InvokeResult.Stop);
+        await Should.ThrowAsync<Exception>(async () =>
+        {
+            var result = await continuation.ExecuteInlineAsync(Substitute.For<IEnvelopeLifecycle>(),
+                new MockWolverineRuntime(), DateTimeOffset.UtcNow, null, CancellationToken.None);
+
+        });
+
         wasCalled.ShouldBeFalse();
     }
 

src/Wolverine/ErrorHandling/FailureRuleCollection.cs

@@ -71,6 +71,16 @@ internal IContinuation DetermineExecutionContinuation(Exception e, Envelope enve
                 continue;
             }
 
+            if (continuation is CompositeContinuation composite)
+            {
+                foreach (var inner in composite.Inner)
+                {
+                    if (inner is IInlineContinuation inline) return inline;
+                }
+                
+                continue;
+            }
+
             if (continuation is IInlineContinuation retry)
             {
                 return retry;

src/Wolverine/ErrorHandling/PolicyExpression.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using System.Runtime.ExceptionServices;
 using Wolverine.ErrorHandling.Matches;
 using Wolverine.Runtime;
 using Wolverine.Runtime.Handlers;
@@ -371,10 +372,14 @@ public ValueTask ExecuteAsync(IEnvelopeLifecycle lifecycle, IWolverineRuntime ru
     public async ValueTask<InvokeResult> ExecuteInlineAsync(IEnvelopeLifecycle lifecycle, IWolverineRuntime runtime, DateTimeOffset now,
         Activity? activity, CancellationToken cancellation)
     {
-        if (InvokeUsage == null) return InvokeResult.Stop;
+        if (InvokeUsage == null)
+        {
+            ExceptionDispatchInfo.Throw(_exception);
+            return InvokeResult.Stop;
+        }
 
         await _action(runtime, lifecycle, _exception);
-
+        
         return InvokeUsage.Value;
     }
 }