cantools: database as_dbc_string() TypeError using bitstruct.c

Python Version: 3.8.5 Cantools Version 34.2.0+ OS: Windows 10 (1909)

This works fine in cantools version 34.1.0. From the commits it appears there was a change from using bistruct to using bitstruct.c. Reverting this change in 34.2.0 does fix the issue.

Further analysis shows bitstruct was at version 8.10.0, updating to 8.11.1 can also resolve the issue.

I am no expert but I think this means that the setup.py needs to have the required bitstruct version upped?

Test code

import cantools
dbc = cantools.database.load_file("vehicle.dbc",strict=False)
cantools.database.dump_file(dbc,"vehicle2.dbc")

Error Messages

  File "c:\anaconda3\envs\py38-logger-tool\lib\site-packages\cantools\database\__init__.py", line 216, in dump_file
    output = database.as_dbc_string()
  File "c:\anaconda3\envs\py38-logger-tool\lib\site-packages\cantools\database\can\database.py", line 279, in as_dbc_string
    return dbc.dump_string(InternalDatabase(self._messages,
  File "c:\anaconda3\envs\py38-logger-tool\lib\site-packages\cantools\database\can\formats\dbc.py", line 1524, in dump_string
    database = deepcopy(database)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 172, in deepcopy
    y = _reconstruct(x, memo, *rv)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 270, in _reconstruct
    state = deepcopy(state, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 146, in deepcopy
    y = copier(x, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 230, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 146, in deepcopy
    y = copier(x, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 205, in _deepcopy_list
    append(deepcopy(a, memo))
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 172, in deepcopy
    y = _reconstruct(x, memo, *rv)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 270, in _reconstruct
    state = deepcopy(state, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 146, in deepcopy
    y = copier(x, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 230, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 146, in deepcopy
    y = copier(x, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 230, in _deepcopy_dict
    y[deepcopy(key, memo)] = deepcopy(value, memo)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 172, in deepcopy
    y = _reconstruct(x, memo, *rv)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 264, in _reconstruct
    y = func(*args)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 263, in <genexpr>
    args = (deepcopy(arg, memo) for arg in args)
  File "c:\anaconda3\envs\py38-logger-tool\lib\copy.py", line 161, in deepcopy
    rv = reductor(4)
TypeError: cannot pickle 'bitstruct.c.CompiledFormatDict' object