Stacktrace on badly formed CAN_ErrorFrame (?)

[johnMediaOnFire]

Describe the bug

We have an MF4 file from Kvaser that causes the following stack trace when run:

Traceback (most recent call last):
 File "load.py", line 43, in <module>
 sys.exit(main(args))
 File "load.py", line 27, in main
 for msg in can.LogReader(args.mf4_file):
 File "/home/john/.pyenv/versions/3.8.20/lib/python3.8/heapq.py", line 373, in merge
 value = next()
 File "/home/john/tmp/keep_1y/python-can/can/io/mf4.py", line 410, in __iter__
 kv["data"] = data["CAN_ErrorFrame.DataBytes"][i][
IndexError: invalid index to scalar variable.

The test code is essentially:

for msg in can.LogReader(mf4_file):
 if msg.is_error_frame:
 count["error"] += 1
 else:
 count["other"] += 1

I put some debug at site of the error (line 407 of can/io/mf4.py):

data_length=4
data["CAN_ErrorFrame.DataBytes"][i]=16777216

2^24?

To Reproduce

I was unable to create a file with python-can with the error data.

Expected behavior

No crash. :)

Additional context

OS and version: Linux
Python version: 3.8.20
python-can version: 654a02a 2024-11-28 | Changelog for v4.5.0 (#1897) (HEAD -> main, origin/main, origin/HEAD)
python-can interface/s (if applicable): None

Traceback and logs

If I make this hack it consumes the error frame:

diff --git a/can/io/mf4.py b/can/io/mf4.py
index 4f5336b4..099395b4 100644
--- a/can/io/mf4.py
+++ b/can/io/mf4.py
@@ -405,9 +405,9 @@ class MF4Reader(BinaryIOMessageReader):
 and "CAN_ErrorFrame.DataBytes" in names
 ):
 data_length = int(data["CAN_ErrorFrame.DataLength"][i])
- kv["data"] = data["CAN_ErrorFrame.DataBytes"][i][
+ kv["data"] = data["CAN_ErrorFrame.DataBytes"][i].tobytes()[
 :data_length
- ].tobytes()
+ ]

 yield Message(**kv)