Fixing memory leak in neoVI bus where message_receipts grows

message_receipts was growing without bound on msg Rx side

Author: pierreluctg

can/interfaces/ics_neovi/neovi_bus.py

@@ -318,7 +318,7 @@ def _process_msg_queue(self, timeout=0.1):
             if is_tx:
                 if bool(ics_msg.StatusBitField & ics.SPY_STATUS_GLOBAL_ERR):
                     continue
-                if ics_msg.DescriptionID:
+                if ics_msg.DescriptionID and receipt_key in self.message_receipts:
                     receipt_key = (ics_msg.ArbIDOrHeader, ics_msg.DescriptionID)
                     self.message_receipts[receipt_key].set()
                 if not self._receive_own_messages:
@@ -477,11 +477,10 @@ def send(self, msg, timeout=0):
         else:
             raise ValueError("msg.channel must be set when using multiple channels.")
 
-        msg_desc_id = next(description_id)
-        message.DescriptionID = msg_desc_id
-        receipt_key = (msg.arbitration_id, msg_desc_id)
-
         if timeout != 0:
+            msg_desc_id = next(description_id)
+            message.DescriptionID = msg_desc_id
+            receipt_key = (msg.arbitration_id, msg_desc_id)
             self.message_receipts[receipt_key].clear()
 
         try:
@@ -492,5 +491,9 @@ def send(self, msg, timeout=0):
         # If timeout is set, wait for ACK
         # This requires a notifier for the bus or
         # some other thread calling recv periodically
-        if timeout != 0 and not self.message_receipts[receipt_key].wait(timeout):
-            raise CanTimeoutError("Transmit timeout")
+        if timeout != 0:
+            got_receipt = self.message_receipts[receipt_key].wait(timeout)
+            # We no longer need this receipt, so no point keeping it in memory
+            del self.message_receipts[receipt_key]
+            if not got_receipt:
+                raise CanTimeoutError("Transmit timeout")