Handle ROUTING_APP error response in onResponseTraceRoute

meshtastic/mesh_interface.py

@@ -687,6 +687,13 @@ def sendTraceRoute(
 
     def onResponseTraceRoute(self, p: dict):
         """on response for trace route"""
+        if p["decoded"]["portnum"] == "ROUTING_APP":
+            error = p["decoded"]["routing"]["errorReason"]
+            if error != "NONE":
+                print(f"Traceroute failed: {error}")
+            self._acknowledgment.receivedTraceRoute = True
+            return
+
         UNK_SNR = -128 # Value representing unknown SNR
 
         routeDiscovery = mesh_pb2.RouteDiscovery()

meshtastic/tests/test_mesh_interface.py

@@ -757,3 +757,43 @@ def test_timeago_fuzz(seconds):
     """Fuzz _timeago to ensure it works with any integer"""
     val = _timeago(seconds)
     assert re.match(r"(now|\d+ (secs?|mins?|hours?|days?|months?|years?))", val)
+
+
+@pytest.mark.unit
+@pytest.mark.usefixtures("reset_mt_config")
+def test_onResponseTraceRoute_routing_error(capsys):
+    """Test that onResponseTraceRoute handles ROUTING_APP error packets correctly."""
+    iface = MeshInterface(noProto=True)
+
+    packet = {
+        "decoded": {
+            "portnum": "ROUTING_APP",
+            "routing": {"errorReason": "MAX_RETRANSMIT"},
+        }
+    }
+
+    iface.onResponseTraceRoute(packet)
+
+    assert iface._acknowledgment.receivedTraceRoute is True
+    out, _ = capsys.readouterr()
+    assert "Traceroute failed: MAX_RETRANSMIT" in out
+
+
+@pytest.mark.unit
+@pytest.mark.usefixtures("reset_mt_config")
+def test_onResponseTraceRoute_routing_none(capsys):
+    """Test that onResponseTraceRoute does not print error for ROUTING_APP with NONE errorReason."""
+    iface = MeshInterface(noProto=True)
+
+    packet = {
+        "decoded": {
+            "portnum": "ROUTING_APP",
+            "routing": {"errorReason": "NONE"},
+        }
+    }
+
+    iface.onResponseTraceRoute(packet)
+
+    assert iface._acknowledgment.receivedTraceRoute is True
+    out, _ = capsys.readouterr()
+    assert "Traceroute failed" not in out