Vector: use global channel_index if provided (#1681)

* fix XL_ERR_INVALID_CHANNEL_MASK for multiple devices with the same serial

* add CHANGELOG.md entry

CHANGELOG.md

@@ -16,6 +16,7 @@ Bug Fixes
 * Fix BLFReader error for incomplete or truncated stream (#1662)
 * PCAN: remove Windows registry check to fix 32bit compatibility (#1672)
 * Vector: Skip the `can_op_mode check` if the device reports `can_op_mode=0` (#1678)
+* Vector: using the config from `detect_available_configs` might raise XL_ERR_INVALID_CHANNEL_MASK error (#1681)
 
 Features
 --------

can/interfaces/vector/canlib.py

@@ -202,12 +202,20 @@ def __init__(
         self._can_protocol = CanProtocol.CAN_FD if is_fd else CanProtocol.CAN_20
 
         for channel in self.channels:
-            channel_index = self._find_global_channel_idx(
-                channel=channel,
-                serial=serial,
-                app_name=app_name,
-                channel_configs=channel_configs,
-            )
+            if (_channel_index := kwargs.get("channel_index", None)) is not None:
+                # VectorBus._detect_available_configs() might return multiple
+                # devices with the same serial number, e.g. if a VN8900 is connected via both USB and Ethernet
+                # at the same time. If the VectorBus is instantiated with a config, that was returned from
+                # VectorBus._detect_available_configs(), then use the contained global channel_index
+                # to avoid any ambiguities.
+                channel_index = cast(int, _channel_index)
+            else:
+                channel_index = self._find_global_channel_idx(
+                    channel=channel,
+                    serial=serial,
+                    app_name=app_name,
+                    channel_configs=channel_configs,
+                )
             LOG.debug("Channel index %d found", channel)
 
             channel_mask = 1 << channel_index
@@ -950,6 +958,7 @@ def _detect_available_configs() -> List[AutoDetectedConfig]:
                     "interface": "vector",
                     "channel": channel_config.hw_channel,
                     "serial": channel_config.serial_number,
+                    "channel_index": channel_config.channel_index,
                     # data for use in VectorBus.set_application_config():
                     "hw_type": channel_config.hw_type,
                     "hw_index": channel_config.hw_index,

test/test_vector.py

@@ -118,6 +118,22 @@ def test_bus_creation() -> None:
     bus.shutdown()
 
 
+@pytest.mark.skipif(not XLDRIVER_FOUND, reason="Vector XL API is unavailable")
+def test_bus_creation_channel_index() -> None:
+    channel_index = 3
+    bus = can.Bus(
+        channel=0,
+        serial=_find_virtual_can_serial(),
+        channel_index=channel_index,
+        interface="vector",
+    )
+    assert isinstance(bus, canlib.VectorBus)
+    assert bus.protocol == can.CanProtocol.CAN_20
+    assert bus.channel_masks[0] == 1 << channel_index
+
+    bus.shutdown()
+
+
 def test_bus_creation_bitrate_mocked(mock_xldriver) -> None:
     bus = can.Bus(channel=0, interface="vector", bitrate=200_000, _testing=True)
     assert isinstance(bus, canlib.VectorBus)
@@ -833,6 +849,31 @@ def test_get_channel_configs() -> None:
     canlib._get_xl_driver_config = _original_func
 
 
+@pytest.mark.skipif(
+    sys.byteorder != "little", reason="Test relies on little endian data."
+)
+def test_detect_available_configs() -> None:
+    _original_func = canlib._get_xl_driver_config
+    canlib._get_xl_driver_config = _get_predefined_xl_driver_config
+
+    available_configs = canlib.VectorBus._detect_available_configs()
+
+    assert len(available_configs) == 5
+
+    assert available_configs[0]["interface"] == "vector"
+    assert available_configs[0]["channel"] == 2
+    assert available_configs[0]["serial"] == 1001
+    assert available_configs[0]["channel_index"] == 2
+    assert available_configs[0]["hw_type"] == xldefine.XL_HardwareType.XL_HWTYPE_VN8900
+    assert available_configs[0]["hw_index"] == 0
+    assert available_configs[0]["supports_fd"] is True
+    assert isinstance(
+        available_configs[0]["vector_channel_config"], VectorChannelConfig
+    )
+
+    canlib._get_xl_driver_config = _original_func
+
+
 @pytest.mark.skipif(not IS_WINDOWS, reason="Windows specific test")
 def test_winapi_availability() -> None:
     assert canlib.WaitForSingleObject is not None