fix(workflow): add missing FailureDetails property to proto converter

src/Dapr.Workflow/Client/ProtoConverters.cs

@@ -32,7 +32,8 @@ public static WorkflowMetadata ToWorkflowMetadata(Dapr.DurableTask.Protobuf.Work
         {
             SerializedInput = string.IsNullOrEmpty(state.Input) ? null : state.Input,
             SerializedOutput = string.IsNullOrEmpty(state.Output) ? null : state.Output,
-            SerializedCustomStatus = string.IsNullOrEmpty(state.CustomStatus) ? null : state.CustomStatus
+            SerializedCustomStatus = string.IsNullOrEmpty(state.CustomStatus) ? null : state.CustomStatus,
+            FailureDetails = ToWorkflowTaskFailureDetails(state.FailureDetails),
         };
 
     /// <summary>
@@ -91,4 +92,12 @@ public static WorkflowHistoryEventType ToHistoryEventType(HistoryEvent.EventType
             HistoryEvent.EventTypeOneofCase.DetachedWorkflowInstanceCreated => WorkflowHistoryEventType.SubOrchestrationInstanceCreated,
             _ => WorkflowHistoryEventType.Unknown
         };
+
+    private static Workflow.WorkflowTaskFailureDetails? ToWorkflowTaskFailureDetails(TaskFailureDetails? failureDetails)
+        => failureDetails is null
+            ? null
+            : new Workflow.WorkflowTaskFailureDetails(
+                failureDetails.ErrorType,
+                failureDetails.ErrorMessage,
+                string.IsNullOrEmpty(failureDetails.StackTrace) ? null : failureDetails.StackTrace);
 }

test/Dapr.Workflow.Test/Client/ProtoConvertersTests.cs

@@ -125,6 +125,32 @@ public void ToWorkflowMetadata_ShouldSetSerializedFieldsToNull_WhenProtoStringsA
         Assert.Null(metadata.SerializedCustomStatus);
     }
 
+    [Fact]
+    public void ToWorkflowMetadata_ShouldMapFailureDetails_WhenPresent()
+    {
+        var serializer = new JsonDaprSerializer();
+
+        var state = new Dapr.DurableTask.Protobuf.WorkflowState
+        {
+            InstanceId = "i",
+            Name = "n",
+            WorkflowStatus = OrchestrationStatus.Failed,
+            FailureDetails = new TaskFailureDetails
+            {
+                ErrorType = "System.InvalidOperationException",
+                ErrorMessage = "boom",
+                StackTrace = "trace"
+            }
+        };
+
+        var metadata = ProtoConverters.ToWorkflowMetadata(state, serializer);
+
+        Assert.NotNull(metadata.FailureDetails);
+        Assert.Equal("System.InvalidOperationException", metadata.FailureDetails!.ErrorType);
+        Assert.Equal("boom", metadata.FailureDetails.ErrorMessage);
+        Assert.Equal("trace", metadata.FailureDetails.StackTrace);
+    }
+
     [Fact]
     public void ToWorkflowMetadata_ShouldKeepSerializedFields_WhenProtoStringsContainWhitespace()
     {