From dd6a8b5eab299160c2a2a16a8da470ad422e9be9 Mon Sep 17 00:00:00 2001
From: Alexander Entinger <cto@lxrobotics.com>
Date: Wed, 8 Nov 2023 12:30:45 +0100
Subject: [PATCH] Fix: do not automatically assume a MTU !=
 CANARD_MTU_CAN_CLASSIC (8) is CAN_FD, do a dedicated check instead. (#260)

---
 src/CanRxQueueItem.hpp | 3 +--
 src/Node.cpp           | 4 ++--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/CanRxQueueItem.hpp b/src/CanRxQueueItem.hpp
index 011caee5..b76c753f 100644
--- a/src/CanRxQueueItem.hpp
+++ b/src/CanRxQueueItem.hpp
@@ -31,8 +31,7 @@ namespace cyphal
 template<size_t MTU_BYTES>
 class CanRxQueueItem
 {
-  static_assert((MTU_BYTES
-  == CANARD_MTU_CAN_CLASSIC) || (MTU_BYTES == CANARD_MTU_CAN_FD),
+  static_assert((MTU_BYTES == CANARD_MTU_CAN_CLASSIC) || (MTU_BYTES == CANARD_MTU_CAN_FD),
   "CanRxQueueItem can only have an MTU size of either 8 (CANARD_MTU_CAN_CLASSIC) or 64 (CANARD_MTU_CAN_FD).");
 public:
   CanRxQueueItem()
diff --git a/src/Node.cpp b/src/Node.cpp
index 91c90229..e9b10006 100644
--- a/src/Node.cpp
+++ b/src/Node.cpp
@@ -116,7 +116,7 @@ void Node::onCanFrameReceived(CanardFrame const & frame)
     CanRxQueueItem<CANARD_MTU_CAN_CLASSIC> const rx_queue_item(&frame, _micros_func());
     static_cast<CircularBufferCan *>(_canard_rx_queue.get())->enqueue(rx_queue_item);
   }
-  else
+  else if (_mtu_bytes == CANARD_MTU_CAN_FD)
   {
     CanRxQueueItem<CANARD_MTU_CAN_FD> const rx_queue_item(&frame, _micros_func());
     static_cast<CircularBufferCanFd *>(_canard_rx_queue.get())->enqueue(rx_queue_item);
@@ -172,7 +172,7 @@ void Node::processRxQueue()
     processRxFrame(rx_queue_item);
     can_rx_queue_ptr->pop();
   }
-  else
+  else if (_mtu_bytes == CANARD_MTU_CAN_FD)
   {
     CircularBufferCanFd * canfd_rx_queue_ptr = static_cast<CircularBufferCanFd *>(_canard_rx_queue.get());
     CanRxQueueItem<CANARD_MTU_CAN_FD> const * rx_queue_item = canfd_rx_queue_ptr->peek();