From 52a2938ffbaac3e7978b844856b4e6dbc4d364ae Mon Sep 17 00:00:00 2001
From: Copilot <223556219+Copilot@users.noreply.github.com>
Date: Sat, 11 Apr 2026 08:36:39 +0000
Subject: [PATCH] fix: read span error message from failureDetails for failed
 orchestrations

setOrchestrationStatusFromActions() was reading the error message from
completeAction.getResult(), but failed orchestrations store the error in
failureDetails (not result). This caused all failed orchestration spans to
show the generic 'Orchestration failed' message instead of the actual error.

Now reads from failureDetails.getErrormessage() first, with fallback to
result for backwards compatibility.

Fixes #218

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .../src/tracing/trace-helper.ts               |  9 +++-
 packages/durabletask-js/test/tracing.spec.ts  | 50 +++++++++++++++++--
 2 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/packages/durabletask-js/src/tracing/trace-helper.ts b/packages/durabletask-js/src/tracing/trace-helper.ts
index aecbb46..01e596a 100644
--- a/packages/durabletask-js/src/tracing/trace-helper.ts
+++ b/packages/durabletask-js/src/tracing/trace-helper.ts
@@ -690,9 +690,14 @@ export function setOrchestrationStatusFromActions(
         span.setAttribute(DurableTaskAttributes.TASK_STATUS, statusName);
       }
 
-      // Match .NET: set span error status when orchestration completes with Failed
+      // Match .NET: set span error status when orchestration completes with Failed.
+      // Read error message from failureDetails (where setFailed() stores it),
+      // falling back to result for backwards compatibility.
       if (status === pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED) {
-        const errorMessage = completeAction.getResult()?.getValue() ?? "Orchestration failed";
+        const errorMessage =
+          completeAction.getFailuredetails()?.getErrormessage() ||
+          completeAction.getResult()?.getValue() ||
+          "Orchestration failed";
         span.setStatus({ code: otel.SpanStatusCode.ERROR, message: errorMessage });
       } else {
         span.setStatus({ code: otel.SpanStatusCode.OK });
diff --git a/packages/durabletask-js/test/tracing.spec.ts b/packages/durabletask-js/test/tracing.spec.ts
index 4e2dfa0..c5d447f 100644
--- a/packages/durabletask-js/test/tracing.spec.ts
+++ b/packages/durabletask-js/test/tracing.spec.ts
@@ -1124,15 +1124,17 @@ describe("Trace Helper - setOrchestrationStatusFromActions", () => {
     expect(spans[0].status.code).toBe(otel.SpanStatusCode.OK);
   });
 
-  it("should set status attribute for failed orchestration and ERROR span status", () => {
+  it("should set status attribute for failed orchestration and ERROR span status with failureDetails", () => {
     const tracer = otel.trace.getTracer(TRACER_NAME);
     const span = tracer.startSpan("orch-status-failed");
 
+    // Match the real runtime path: setFailed() sets failureDetails but NOT result
     const completeAction = new pb.CompleteOrchestrationAction();
     completeAction.setOrchestrationstatus(pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED);
-    const resultValue = new StringValue();
-    resultValue.setValue("User code threw an error");
-    completeAction.setResult(resultValue);
+    const failureDetails = new pb.TaskFailureDetails();
+    failureDetails.setErrormessage("User code threw an error");
+    failureDetails.setErrortype("Error");
+    completeAction.setFailuredetails(failureDetails);
 
     const action = new pb.OrchestratorAction();
     action.setCompleteorchestration(completeAction);
@@ -1146,6 +1148,46 @@ describe("Trace Helper - setOrchestrationStatusFromActions", () => {
     expect(spans[0].status.message).toBe("User code threw an error");
   });
 
+  it("should fall back to result field for failed orchestration error message", () => {
+    const tracer = otel.trace.getTracer(TRACER_NAME);
+    const span = tracer.startSpan("orch-status-failed-result-fallback");
+
+    // Edge case: no failureDetails, but result is set (backwards compatibility)
+    const completeAction = new pb.CompleteOrchestrationAction();
+    completeAction.setOrchestrationstatus(pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED);
+    const resultValue = new StringValue();
+    resultValue.setValue("Legacy error message");
+    completeAction.setResult(resultValue);
+
+    const action = new pb.OrchestratorAction();
+    action.setCompleteorchestration(completeAction);
+
+    setOrchestrationStatusFromActions(span, [action]);
+    span.end();
+
+    const spans = exporter.getFinishedSpans();
+    expect(spans[0].status.code).toBe(otel.SpanStatusCode.ERROR);
+    expect(spans[0].status.message).toBe("Legacy error message");
+  });
+
+  it("should use default error message when neither failureDetails nor result is set", () => {
+    const tracer = otel.trace.getTracer(TRACER_NAME);
+    const span = tracer.startSpan("orch-status-failed-no-details");
+
+    const completeAction = new pb.CompleteOrchestrationAction();
+    completeAction.setOrchestrationstatus(pb.OrchestrationStatus.ORCHESTRATION_STATUS_FAILED);
+
+    const action = new pb.OrchestratorAction();
+    action.setCompleteorchestration(completeAction);
+
+    setOrchestrationStatusFromActions(span, [action]);
+    span.end();
+
+    const spans = exporter.getFinishedSpans();
+    expect(spans[0].status.code).toBe(otel.SpanStatusCode.ERROR);
+    expect(spans[0].status.message).toBe("Orchestration failed");
+  });
+
   it("should not set status when no completion action present", () => {
     const tracer = otel.trace.getTracer(TRACER_NAME);
     const span = tracer.startSpan("orch-status-none");